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rev.2.3 _00 step-up, for lcd bias supply, 1-channel, pwm control switching regu lator controller s-8333 series seiko instruments inc. 1 the s-8333 series is a cmos step-up switching regulator which mainly consists of a reference voltage circuit, an oscillator, an error amplifier, a pwm controller, an under voltage lockout circuit (uvlo), and a timer latch short-circuit prot ection circuit. because its minimum operating voltage is as low as 1.8 v, this switching regulator is ideal for the power supply of an lcd or for portable systems that operate on a low voltage. the internal oscillation frequency can be set up to 1.133 mhz, via the resistor connected to the rosc pin. the maximum duty ratio of pwm control can be controlled by the resistor connected to the rduty pin. the soft-start function at power application is accompli shed by combining the reference voltage control and maximum duty control methods. even if the voltage of the fb pin is retained lower than the reference voltage due to the factor outside the ic, the output volt age is raised by controlling the maximum duty. the phase compensation and gain value can be adjusted according to the values of the resistor and capacitor connected to the cc pin. therefore, the operation st ability and transient response can be correctly set for each application. the reference voltage accuracy is as high as 1.0 v 1.5%, and any voltage can be output by using an external output voltage setting resistor. in addition, the delay time of the short-circuit protection circuit can be set by using the capacitor connected to the csp pin. if the maximum duty condition continues because of short-circuiting, the capacitor externally connected to the csp pin is charg ed, and oscillation stops af ter a specific time. the short-circuit protection function is cancelled when the power supply is raised to the uvlo release voltage after it has been lowered to the uvlo detection volta ge. a ceramic capacitor or a tantalum capacitor is used as the output capacitor, depending on the setting. this controller ic allows various settings and selections and employs a small package, making it very easy to use. features ? low voltage operation: 1.8 v to 6.0 v ? oscillation frequency: 286 khz to 1.133 mhz (selectable by external resistor) ? maximum duty: settable up to 88.5% by external resistor 47 to 88.5% (oscillation frequency; 500 khz or more) 47 to 80% (oscillation frequency; less than 500 khz) ? reference voltage: 1.0 v 1.5% ? range of operation temperature: ? 40 to + 85 c ? uvlo (under-voltage lockout) function: detection voltage can be selected from between 1.5 v and 2.3 v in 0.1 v step. hysteresis width can be selected from between 0.1 v and 0.3 v in 0.1 v step. ? timer latch short-circuit protection circuit: delay time can be set using an external capacitor. ? soft-start function: soft-start time can be se lected in three steps, 10 ms, 15 ms, and 20 ms. both reference voltage control and maximum duty control methods are applied ? phase compensation external setting: control is possible via the resistor connected between the cc and gnd pins and capacitor ? small package: snt-8a, 8-pin tssop ? lead-free products applications ? power supplies for lcds and ccds ? power supplies for portable equipment packages drawing code package name package tape reel land snt-8a ph008-a ph0 08-a ph008-a ph008-a 8-pin tssop ft008-a ft008-e ft008-e ?
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller s-8333 series rev.2.3 _00 seiko instruments inc. 2 block diagram pwm comparator v out timer latch short-circuit p rotection circuit rduty rfb2 vss rfb1 fb sd l vin ext uvlo csp cc rz cz rosc m1 cfb + ? + ? oscillator maximum duty soft-start circuit reference voltage (1.0 v) soft-start circuit error amplifier c in c l figure 1 block diagram
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller rev.2.3 _00 s-8333 series seiko instruments inc. 3 product name structure 1. product name s-8333 a x x x - xxxx g package name(abbreviation) and packing specifications i8t1: snt-8a, tape t8t1: 8-pin tssop, tape soft-start time setting a: 10 ms b: 15 ms c: 20 ms uvlo setting a: 2.3 v b: 2.2 v c: 2.1 v d: 2.0 v e: 1.9 v f: 1.8 v g: 1.7 v h: 1.6 v i: 1.5 v uvlo hysteresis setting a: 0.1 v b: 0.2 v c: 0.3 v
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller s-8333 series rev.2.3 _00 seiko instruments inc. 4 pin configurations table 1 pin no. symbol description 1 cc error amplifier circuit output phase compensation pin 2 fb output voltage feedback pin 3 csp short-circuit protection delay time setting pin 4 vin power supply input pin 5 ext external transistor connection pin 6 vss gnd pin 1 2 3 4 snt-8a top view 8 7 6 5 7 rosc oscillation frequency setting resistor connection pin figure 2 8 rduty maximum duty setting resistor connection pin table 2 pin no. symbol description 1 cc error amplifier circuit output phase compensation pin 2 fb output voltage feedback pin 3 csp short-circuit protection delay time setting pin 4 vin power supply input pin 5 ext external transistor connection pin 6 vss gnd pin 8-pin tssop top view 1 3 2 4 8 6 7 5 7 rosc oscillation frequency setting resistor connection pin figure 3 8 rduty maximum duty setting resistor connection pin
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller rev.2.3 _00 s-8333 series seiko instruments inc. 5 absolute maximum ratings table 3 absolute maximum ratings (unless otherwise specified: ta = 25 c, v ss = 0 v) parameter symbol ratings unit vin pin voltage v in v ss ? 0.3 to v ss + 6.5 v fb pin voltage v fb v ss ? 0.3 to v ss + 6.5 v ext pin voltage v ext v ss ? 0.3 to v in + 0.3 v csp pin voltage v csp v ss ? 0.3 to v in + 0.3 v cc pin voltage v cc v ss ? 0.3 to v in + 0.3 v cc pin current i cc 10 ma rosc pin voltage v rosc v ss ? 0.3 to v in + 0.3 v rosc pin current i rosc 10 ma rduty pin voltage v rduty v ss ? 0.3 to v in + 0.3 v rduty pin current i rduty 10 ma snt-8a 450 *1 mw 300 (when not mounted on board) mw power dissipation 8-pin tssop p d 700 *1 mw operating ambient temperature t opr ? 40 to + 85 c storage temperature t stg ? 40 to + 125 c *1. when mounted on board [mounted board] (1) board size: 114.3 mm 76.2 mm t1.6 mm (2) name: jedec standard51-7 caution the absolute maximum ratings are rated values exceeding which the product could suffer physical damage. these values must therefore not be exceeded under any conditions. 0 50 100 150 0 ambient temperature (ta) [ c] 600 400 200 8-pin tssop 800 power dissipation (p d ) [mw] snt-8a figure 4 power dissipation of package (when mounted on board)
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller s-8333 series rev.2.3 _00 seiko instruments inc. 6 electrical characteristics table 4 electrical characteristics (unless otherwise specified: v in = 3.3 v, ta = 25 c) parameter symbol conditions min. typ. max. unit test circuit operating input voltage v in ? 1.8 ? 6.0 v 2 fb voltage v fb ? 0.985 1.000 1.015 v 2 current consumption i ss1 f osc = 700 khz v fb = 0.95 v ? 450 700 a 1 i exth v ext = v in ? 0.4 v ? ? 100 ? 60 ma 1 ext pin output current i extl v ext = 0.4 v 100 160 ? ma 1 fb voltage temperature coefficient ? v fb ? ta ta = ? 40 to + 85 c ? 100 ? ppm/ c2 fb pin input current i fb ? ? 0.1 ? + 0.1 a 1 oscillation frequency *1 f osc when f osc = 1133 khz is set (r osc = 120 k ? ) when f osc = 700 khz is set (r osc = 200 k ? ) when f osc = 286 khz is set (r osc = 510 k ? ) v fb = 0.9 v waveform on ext pin is measured. f osc 0.9 f osc f osc 1.1 khz 1 oscillation frequency temperature coefficient ? f osc ? ta ta = ? 40 to + 85 c f osc = 700 khz ? 1000 ? ppm/ c1 f osc = 1133 khz (r osc = 120 k ? ) maxduty = 88.5% (r duty = 62 k ? ) maxduty = 73% (r duty = 180 k ? ) maxduty = 47% (r duty = 390 k ? ) max. duty *2 maxduty f osc = 700 khz (r osc = 200 k ? ) maxduty = 88.5% (r duty = 100 k ? ) maxduty ? 5 maxduty maxduty + 5 % 1 soft-start time t ss t ss = 10 ms, 15 ms, 20 ms selected in three steps t ss 0.75 t ss t ss 1.5 ms 1 short-circuit protection delay time *3 t pro t pro = 50 ms (csp = 0.1 f) 37.5 50 75 ms 1 uvlo detection voltage v uvlo v uvlo = 1.5 v to 2.3 v selected in 0.1 v steps v uvlo 0.95 v uvlo v uvlo 1.05 v 1 uvlo hysteresis width v uvlohys v uvlohys = 0.1 v to 0.3 v selected in 0.1 v steps v uvlohys 0.6 v uvlohys v uvlohys 1.4 v 1 i cch v fb = 2 v ? 75 ? 50 ? 37.5 a 1 cc pin output current i ccl v fb = 0 v 37.5 50 75 a 1 v rtlt1 within short-circuit protection delay time 0.7 1.0 1.3 v 1 timer latch reset voltage v rtlt2 after short-circuit protection circuit operated v uvlo 0.95 v uvlo v uvlo 1.05 v 1 *1. the recommended range of the resistance (r osc ) for oscillation frequency is r osc = 120 k ? to 510 k ? (f osc = 286 khz to 1.133 mhz). this range of oscillation frequency is the typical value when an i deal resistor is connected externally. in actual use, it is n ecessary to take account the dispersion of an ic ( 10%) into this value. *2. set max. duty; between 47 and 88.5 % (r duty /r osc = 0.5 to 3.2); the oscillation frequency is 500 khz or more between 47 and 80 % (r duty /r osc = 1.0 to 3.2); the oscillation frequency is less than 500 khz this range of max. duty is the typical value when an ideal resistor is connected externally. in actu al use, it is necessary to take account the dispersion of an ic ( 5%) into this value. *3. the short-circuit protection time can be set by the external capacitor. although the maximum set value by the external capacit or is unlimited under the ideal condition, set c sp = approx. 0.47 f as a target maximum value due to discharge time of the capacitor.
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller rev.2.3 _00 s-8333 series seiko instruments inc. 7 external parts when measuring electrical characteristics table 5 external parts element name symbol manufacturer part number inductor l tdk corporation ldr655312t 10 h diode sd rohm co., ltd. rb491d output capacitor cl ? ceramic 10 f transistor m1 sanyo electric co., ltd. mch3406 oscillation frequency setting resistor rosc ? 200 k ? (when f osc = 700 khz) maximum duty ratio setting resistor rduty ? 300 k ? (when maxduty = 73%) short-circuit protection delay time setting capacitor csp ? 0.1 f (when t pro = 50 ms) output voltage setting resistor 1 rfb1 ? 8.2 k ? (when v out = 9.2 v) output voltage setting resistor 2 rfb2 ? 1.0 k ? (when v out = 9.2 v) fb pin capacitor cfb ? 180 pf phase compensation resistor rz ? 200 k ? phase compensation capacitor cz ? 0.01 f
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller s-8333 series rev.2.3 _00 seiko instruments inc. 8 measurement circuits 1. cc ext vss fb csp rosc vin a oscilloscope rduty cin csp cz rz rosc rduty figure 5 2. cc ext vss fb csp rosc vin v rduty csp cin m1 cl rfb2 rfb1 cfb rz cz l sd rosc rduty figure 6
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller rev.2.3 _00 s-8333 series seiko instruments inc. 9 operation 1. switching control method 1. 1 pwm control the s-8333 series is a dc-dc converter using a pulse width modulation method (pwm). the pulse width of the s-8333 series varies from 0% to the maximum duty set by rduty depending on the load current, but its switching frequency does not change. c onsequently, the ripple voltage generated from switching can be removed easily via a filter. 2. soft-start function for this ic, the built- in soft-start circuit controls the rush current and overshoot of the output voltage when powering on. reference voltage adjustment and maximum duty control methods are adopted as the soft-start methods. the following describes the so ft-start function at power application. in the circuit where the input voltage is not directly out put at shutdown by inserting a switch (sw) between the diode (sd) and v out output, the v out voltage when the v in voltage is applied with the sw off stays 0 v. therefore, the voltage of the fb pin stays 0 v and the ex t output is in the step up status between the ?h? and ?l? levels due to the maximum duty. the maximum duty at th is time is approximately 7% and the rush current at power application is controlled. the maximum duty soft start is accomplished by gradually increasing the duty width up to the maximum du ty set by the external re sistor rduty (refer to figure 8 ). the reference voltage of the error amplifier input also gradually increases from 0 v at the same time as the maximum duty soft start. the increasing of the output volt age is controlled by turning the sw on. the soft-start function is realized by controlling the voltage of the fb pin so that it is the same potential as the reference voltage that is slowly raised. a rail-to-rail amplifier is adopted as the error amplifier, whic h means that the voltage is loop controlled so that it can be th e same as the reference voltage. once the reference voltage rises, the voltage cannot be reset (the reference voltage is 0 v) unless making the power supply voltage lower than the uvlo detection voltage. conversely, when the power supply voltage rises up to the reset voltage after it is lowered to the uvlo dete ction voltage or lower, the output voltage is stepped up by the soft-start function. pwm comparator v out rfb2 rfb1 fb sd l v in ext cc rz cz m1 + ? c l error amplifier v ref 0.5 v 0 v + ? error amplifier reference voltage sw figure 7
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller s-8333 series rev.2.3 _00 seiko instruments inc. 10 (v in = 0 v 3.3 v, v out = 9.2 v, r fb1 = 8.2 k ? , r fb2 = 1.0 k ? ) 0 v input voltage (v in ) 3.3 v 0 v output voltage (v out ) sw : on 0 v error amplifier reference voltage 1.0 v 0 v fb pin voltage (v fb ) 1.0 v 0 v ext pin voltage (v ext ) 3.3 v t (ms) v out 0.95 maximum duty soft-start period 9.2 v reference voltage soft-start period t ss figure 8
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller rev.2.3 _00 s-8333 series seiko instruments inc. 11 3. timer latch short-circuit protection function this ic has a timer latch short-circuit protection circuit that stops the switching operation when the output voltage drops for a specific time due to output short-circuiting. a ca pacitor (csp) that is used to set the delay time of this short-circuit protection circuit can be connected to the csp pin. this ic operates at the maximum duty ratio if the outp ut voltage drops due to output short-circuiting. at the maximum duty ratio, constant-current charging of csp starts. if this status lasts for a short-circuit protection delay time and the csp pin voltage rises above the reference voltage, the latch mode is set. note that the latch mode is different from the shutdown status in that the switching operation is stopped but the internal circuitry operates normally. to reset the latch operation to protect the ic from short-circuiting, lower v in than the uvlo detection voltage. the latch mode within the short-circuit protection delay time is reset by decreasing v in to 1.0 v (typ.) or lower. note that the mode is not reset even if the v in is lowered to the uvlo detection voltage (refer to figure 9 ). input voltage (v in ) output load csp pin voltage (v csp ) latch mode short-circuit status 50 ms (csp = 0.1 ) figure 9 4. uvlo function this ic includes a uvlo (under-voltage lockout) circuit to prevent the ic from malfunctioning due to a transient status when power is applied or a momentary drop of the power supply voltage. when uvlo is in the detection state, switching is stopped and the external fet is held in the off status. once uvlo enters the detection state, the soft-start function is reset. note that the other internal circuits operate normally and that the status is different from the power-off status.
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller s-8333 series rev.2.3 _00 seiko instruments inc. 12 5. error amplifier the error amplifier outputs the pwm control signal so that t he voltage of the fb pin is held at a specific value (1 v). by connecting a resistor (rz) and capacitor (cz) to the output pin (cc pin) of the error amplifier in series, an optional loop gain can be set, enabling stabilized phase compensation. 6. operation the following are basic equations [(1) through (7)] of the step-up switching regulator (refer to figure 10 ). d l c l m1 fb cont v in ext vss v out figure 10 step-up switching regulator circuit for basic equations voltage at the cont pin at the moment m1 is turned on (current i l flowing through l is zero), v a : v a = v s *1 .............................................................................................................................. ................... (1) *1. v s : non-saturated voltage of m1 change in i l over time: l v v l v dt dl s in l l ? = = ............................................................................................................................. (2 ) integration of the above equation: t l v v i s in l ? ? ? ? ? ? ? ? ? = ............................................................................................................................... ..... (3) i l flows while m1 is on (t on ). this time is determined by the oscillation frequency of osc. peak current (i pk ) after t on : on s in pk t l v v i ? ? ? ? ? ? ? ? ? = .............................................................................................................................. ( 4) the energy stored in l is represented by () 2 pk i l 2 1 . when m1 is turned off (t off ), the energy stored in l is released via a diode, generating a reverse voltage (v l ). v l : ( ) ? + = ......................................................................................................................... (5) *2. v d : diode forward voltage the voltage on the cont pin rises only by v out + v d .
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller rev.2.3 _00 s-8333 series seiko instruments inc. 13 change in current (i l ) flowing through the diode into v out during t off : l v v v l v dt di in d out l l ? + = = ................................................................................................................. (6) integration of the above equation is as follows: t l v v v i i in d out pk l ? ? ? ? ? ? ? ? ? + ? = ............................................................................................................... (7) during t on , energy is stored in l and is not transmitted to v out . when receiving output current (i out ) from v out , the energy of the capacitor (c l ) is used. as a result, the pin voltage of c l is reduced, and goes to the lowest level after m1 is turned on (t on ). when m1 is turned off, the energy stored in l is transmitted via the diode to c l , and the pin voltage of c l rises drastically. because v out is a time function indicating the maximum value (ripple voltage: v p-p ) when the current flowing through the diode into v out and the load current i out match. next, this ripple voltage is determined as follows. i out vs t 1 (time) from after t on , when v out reaches the maximum level: 1 in d out pk out t l v v v i i ? ? ? ? ? ? ? ? ? + ? = .......................................................................................................... (8) () ? ? ? ? ? ? ? ? ? + ? = in d out out pk 1 v v v l i i t ......................................................................................................... (9) when t off , i l = 0 (when the energy of the inductor is completely transmitted): based on equation (7), pk off in d out i t v v v l = ? ? ? ? ? ? ? ? ? + ............................................................................................................ (10) when substituting equation (10) for equation (9): off pk out off 1 t i i t t ? ? ? ? ? ? ? ? ? = .................................................................................................................... (11) electrical charge ? q 1 which is charged in c l during t 1 : 2 1 in d out 1 pk 1 t 0 in d out 1 t 0 pk 1 t 0 l 1 t 2 1 l v v v t i tdt l v v v dt i dt i q ? + ? = ? + ? = = ? ................. (12) when substituting equation (12) for equation (9): () 1 out pk 1 out pk pk 1 t 2 i i t i i 2 1 i q + = ? ? = ? ................................................................................... (13) a rise voltage (v p-p ) due to ? q 1 : 1 out pk l l 1 p p t 2 i i c 1 c q v ? ? ? ? ? ? ? ? + = ? = ? ................................................................................................... (14) when taking into consideration i out consumed during t 1 and esr *1 (r esr ) of c l : l 1 out esr out pk 1 out pk l l 1 p p c t i r 2 i i t 2 i i c 1 c q v ? ? ? ? ? ? ? ? ? + + ? ? ? ? ? ? ? ? + = ? = ? .............................................. (15) *1. equivalent series resistance when substituting equation (11) for equation (15): esr out pk l off pk 2 out pk p p r 2 i i c t i 2 ) i (i v ? ? ? ? ? ? ? ? + + ? = ? ........................................................................... (16) therefore to reduce the ripple voltage, it is important that the capacitor connected to the output pin has a large capacity and a small esr.
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller s-8333 series rev.2.3 _00 seiko instruments inc. 14 external parts selection 1. inductor the inductance has a strong influence on the maximum output current (i out ) and efficiency ( ). the peak current (i pk ) increases by decreasing l and the st ability of the circuit improves and i out increases. if l is decreased further, the efficiency falls, and i out decreases if the current drive capability of the external transistor is insufficient. the loss of i pk by the switching transistor decreases by increasing l and the efficiency becomes maximum at a certain l value. further increasing l decrease the efficiency due to the loss of the dc resistance of the inductor. i out also decreases. if the oscillation frequency is higher, a smaller l value can be chosen, making the inductor smaller. in the s-8333 series, the oscillation frequency can be varied within the range of 286 khz to 1.133 mhz by the external resistor, so select an l value best suited to the frequency. the recommended value is between 2.2 h and 22 h. when selecting an inductor, note the allowable current of the inductor. if a current exceeding this allowable current flows through the inductor, magnetic saturation occurs, substantially lowering the efficiency and increasing the current, which results in damage to the ic. therefore, select an inductor so that i pk does not exceed the allowable current. i pk is expressed by the following equations in the discontinuous mode and continuous mode. l fosc ) v v (v i 2 i in d out out pk ? + = ) mode ous discontinu ( .................................................................. (17) l fosc ) v (v 2 v ) v v (v i v v v i d out in in d out out in d out pk + ? + + + = mode) s (continuou ........................................................ (18) f osc = oscillation frequency, v d ? 0.4 v. 2. diode use an external diode that meets the following requirements. ? low forward voltage ? high switching speed ? reverse breakdown voltage: v out + [spike voltage] or more ? rated current: i pk or more 3. capacitors (c in , c l ) the capacitor on the input side (c in ) can lower the supply impedance and level the input current for better efficiency. select c in according to the impedance of the power supply to be used. the capacitor on the output side (c l ) is used to smooth the output voltage. select an appropriate capacitance value based on the i/o conditions and load conditions. a capacitance of 10 f or more is recommended. by adjusting the phase compensation of the feedback loop using the external resistor (rz) and capacitor (cz), a ceramic capacitor can be used as the capacitor on the output side. if a capacitor whose equivalent series resistance is between 30 m ? and 500 m ? is used as the output capacitor, the adjustable range of the phase compensation is wider; however, note that other characteristics may be affected by ripple voltage or other conditions at this time. the optimal capacitor differs depending on the l value, capacitance value, wiring, and application (output load), so select the capacitor after performing sufficient evaluation under the actual usage conditions.
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller rev.2.3 _00 s-8333 series seiko instruments inc. 15 4. external transistor a bipolar (npn) or enhancement (n-channel) mos fet transistor can be used as the external capacitor. 4. 1 bipolar (npn) type the driving capability when the output current is increased by using a bipolar transistor is determined by h fe and r b of the bipolar transistor. figure 11 shows a peripheral circuit. nch pch r b v in i pk ext c b 2200 pf 1 k ? figure 11 external transistor periphery 1 k ? is recommended for r b . actually, calculate the necessary base current (i b ) from h fe of the bipolar transistor as follows and select an r b value lower than this. i b = h fe i pk r b = i b v in ? 0.7 ? i exth 0.4 a small r b increases the output current, but the efficiency decreases. actually, a pulsating current flows and a voltage drop occurs due to the wiring capacitance. determine the optimum value by experiment. a speed-up capacitor (c b ) connected in parallel with r b resistance as shown in figure 11 decreases the switching loss and improves the efficiency. select c b by observing the following equation. 7 . 0 f r 2 1 c osc b b however, in practice, the optimum c b value also varies depending on the characteristics of the bipolar transistor employed. therefore, determine the optimum value of c b by experiment. 4. 2 enhancement mos fet type use an nch power mos fet. for high efficiency, using a mos fet with a low on resistance (r on ) and small input capacitance (c iss ) is ideal, however, on resistance and input capacitance generally share a trade-off relationship. the on resistance is efficient in a range in which the output current is relatively great during low-frequency switching, and t he input capacitance is efficient in a range in which the output current is middling during high-frequency switching. select a mos fet whose on resistance and input capacitance are optimal depending on the usage conditions. the input voltage (v in ) is supplied for the gate voltage of the mos fet, so select a mos fet with a gate withstanding voltage that is equal to the maximum usage value of the input voltage or higher and a drain withstanding voltage that is equal to the amount of the output voltage (v out ) and diode voltage (v d ) or higher. if a mos fet with a threshold that is near the uvlo detection voltage is used, a large current may flow, stopping the output voltage from rising and possibly generating heat in the worst case. select a mos fet with a threshold that is sufficiently lower than the uvlo detection voltage value.
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller s-8333 series rev.2.3 _00 seiko instruments inc. 16 5. oscillation frequency and maximum duty ratio setting resistors (rosc, rduty) with the s-8333 series, the oscillation frequency can be set in a range of 286 khz to 1.133 mhz using external resistance. connect a resistor across the rosc and vss pins. select the resistor by using the following equation and referring to figure 12 . however, the following equation and figure assume that the resistance value is the desired value and show the theoretical values when the ic is in the typical conditions. note that fluctuations of resistance and ic are not considered. 140 10 3 r osc [k ? ] ? f osc [khz] 1400 1200 1000 800 600 400 200 0 0 200 400 600 f osc [khz] r osc [k ? ] figure 12 r osc vs. f osc with the s-8333 series, the maximum duty ratio can be set in a range of 47% to 88.5% (between 47 to 80%, if the oscillation frequency is less than 500 khz) by an external resistor. connect the resistor across the rduty and vss pins. select the resistance by usi ng the following equation and referring to figure 13 . the maximum duty ratio fluctuates according to the oscillation frequency. if the value of rosc is changed, therefore, be sure to change the value of rduty so that it is always in proportion to rduty / rosc. however, the following equation and figure assume that the resistance value is the desired value and show the theoretical values when the ic is in the typical conditions. note that fluctuations of resistance and ic are not considered. caution set max. duty 80% or less if the oscillation frequency is less than 500 khz. (95.5 ? maxduty) ? r osc r duty 15.0 100 90 80 70 60 50 40 0 2 4 maxduty [%] r duty / r osc 1 3 figure 13 r duty / r osc vs. maxduty connect resistors rosc and rduty as close to the ic as possible.
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller rev.2.3 _00 s-8333 series seiko instruments inc. 17 6. short-circuit protection delay time setting capacitor (csp) with the s-8333 series, the short-circuit protection delay time can be set to any value by an external capacitor. connect the capacitor across the csp and vss pins. select the capacitance by using the following equation and referring to figure 14 . however, the following equation and figure assume that the capacitor value is the desired value and show the theoretical values when the ic is in the typical conditions. note that fluctuations of capacitor and ic are not considered. c sp [ f] ? 1.0 t pro [ms] 2 10 ? 3 120 100 80 60 40 20 0 0 0.10 0.20 0.25 t pro [ms] c sp [ f] 0.05 0.15 figure 14 c sp vs. t pro 7. output voltage setting resistors (rfb1, rbf2) with the s-8333 series, the output voltage can be set to any value by external divider resistors. connect the divider resistors across the v out and vss pins. because v fb = 1 v, the output voltage can be calculated by this equation. = v out r fb2 (r fb1 + r fb2 ) connect divider resistors rfb1 and rfb2 as close to the ic to minimize effects from of noise. if noise does have an effect, adjust the values of rfb1 and rfb2 so that r fb1 + r fb2 < 100 k ? . cfb connected in parallel with rfb1 is a capacitor for phase compensation. select the optimum value of this capacitor at which the stable operation can be ensured from the values of the inductor and output capacitor. 8. phase compensation setting resistor and capacitor (rz, cz) the s-8333 series needs appropriate compensation for the voltage feedback loop to prevent excessive output ripple and unstable operation from deteriorating the efficiency. this compensation is implemented by connecting rz and cz in series across the cc and vss pins. rz sets the high-frequency gain for a high-speed transient response. cz sets the pole and zero of the error amplifier and keeps the loop stable. adjust rz and cz, taking into consideration conditions such as the inductor, output capacitor, and load current, so that the optimum transient characteristics can be obtained.
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller s-8333 series rev.2.3 _00 seiko instruments inc. 18 standard circuit pwm comparator v out timer latch short-circuit protection circuit rduty rfb2 vss rfb1 fb sd l vin ext uvlo csp cc rz cz rosc m1 cfb + ? + ? c in oscillator maximum duty soft-start circuit reference voltage (1.0 v) soft-start circuit error amplifier 0.1 f rosc rduty c l ground point figure 15 standard circuit caution the above connection diagram and constant will not guarantee successful operation. perform thorough evaluation using the actual application to set the constant.
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller rev.2.3 _00 s-8333 series seiko instruments inc. 19 precaution ? mount external capacitors, diodes, and inductor as close as possible to the ic. ? characteristics ripple voltage and spike noise occur in ic containing switching regulators. moreover rush current flows at the time of a power supply injection. because these largely depend on the inductor, the capacitor and impedance of power supply used, fully check them using an actually mounted model. ? make sure the dissipation of the switching transistor (especially at a high temperature) does not exceed the allowable power dissipation of the package. ? the performance of a switching regulator varies depending on the design of the pcb patterns, peripheral circuits, and external parts. thoroughly test all settings with your device. ? the capacitor, diode, inductor and others used as external parts do not assure the operation at high temperature. evaluate fully using the actual application when designing. ? this ic builds in soft start function, starts reference voltage gradually, and it is controlled so that fb pin voltage and reference voltage become this potential. therefore, keep in mind that it will be in a maximum duty state according to the factor of ic exterior if fb pin voltage is held less than reference voltage. ? although the ic contains a static electricity protection circuit, static electricity or voltage that exceeds the limit of the protection circuit should not be applied. ? seiko instruments inc. assumes no responsibility for the way in which this ic is used on products created using this ic or for the specifications of that product, nor does seiko instruments inc. assume any responsibility for any infringement of patents or copyrights by products that include this ic either in japan or in other countries.
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller s-8333 series rev.2.3 _00 seiko instruments inc. 20 characteristics (typical data) 1. example of major temperature characteristics (ta = ? 40 to 85 c) i ss1 vs. ta (v in = 3.3 v) ? 40 0 20 40 60 80 800 700 600 500 400 300 200 100 0 i ss1 [ a] ta [ c] f osc = 1133 khz (r osc = 120 k ? ) ? 20 100 f osc = 700 khz (r osc = 200 k ? ) f osc = 286 khz (r osc = 510 k ? ) i exth vs. ta (v in = 3.3 v) i extl vs. ta (v in = 3.3 v) ? 40 0 20 40 60 80 ? 200 ? 180 ? 160 ? 140 ? 120 ? 100 ? 80 ? 60 ? 40 ? 20 0 i exth [ma] ta [ c] ? 20 100 f osc = 700 khz, maxduty = 73% (r osc = 200 k ?, r duty = 300 k ? ) ? 40 0 20 40 60 80 200 180 160 140 120 100 80 60 40 20 0 i extl [ma] ta [ c] ? 20 100 f osc = 700 khz, maxduty = 73% (r osc = 200 k ?, r duty = 300 k ? ) i fb vs. ta (v in = 3.3 v) f osc vs. ta (v in = 3.3 v) ? 40 0 20 40 60 80 0.10 0.08 0.06 0.04 0.02 0 ? 0.02 ? 0.04 ? 0.06 ? 0.08 ? 0.10 i fb [ a] ta [ c] ? 20 100 ? 40 0 20 40 60 80 1400 1200 1000 800 600 400 200 0 f osc [khz] ta [ c] ? 20 100 f osc = 1133 khz (r osc = 120 k ? ) f osc = 700 khz (r osc = 200 k ? ) f osc = 286 khz (r osc = 510 k ? ) maxduty vs. ta (v in = 3.3 v) t ss vs. ta (v in = 3.3 v) ? 40 0 20 40 60 80 100 90 80 70 60 50 40 30 20 10 0 maxduty [%] ta [ c] ? 20 100 maxduty = 88.5% (r osc = 200 k ?, r duty = 100 k ? ) maxduty = 73% (r osc = 200 k ?, r duty = 300 k ? ) maxduty = 47% (r osc = 200 k ?, r duty = 640 k ? ) ? 40 0 20406080 25.0 20.0 15.0 10.0 5.0 0 t ss [ms] ta [ c] ? 20 100 t ss = 20 ms t ss = 10 ms
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller rev.2.3 _00 s-8333 series seiko instruments inc. 21 t pro vs. ta (v in = 3.3 v) v uvlo vs. ta ? 40 0 20 40 60 80 70.0 60.0 50.0 40.0 30.0 20.0 10.0 0 t pro [ms] ta [ c] ? 20 100 t pro = 50 ms (csp = 0.1 f) ? 40 0 20 40 60 80 2.5 2.0 1.5 1.0 0.5 0 v uvlo [v] ta [ c] ? 20 100 v uvlo = 2.3 v v uvlo = 1.5 v v uvlohys vs. ta i cch vs. ta (v in = 3.3 v) ? 40 0 20 40 60 80 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0 v uvlohys [v] ta [ c] ? 20 100 v uvlohys = 0.3 v v uvlohys = 0.1 v ? 40 0 20 40 60 80 ? 100 ? 90 ? 80 ? 70 ? 60 ? 50 ? 40 ? 30 ? 20 ? 10 0 i cch [ a] ta [ c] ? 20 100 i ccl vs. ta (v in = 3.3 v) v rtlt1 vs. ta (v in = 3.3 v) ? 40 0 20 40 60 80 100 90 80 70 60 50 40 30 20 10 0 i ccl [ a] ta [ c] ? 20 100 ? 40 0 20 40 60 80 1.2 1.0 0.8 0.6 0.4 0.2 0 v rtlt1 [v] ta [ c] ? 20 100
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller s-8333 series rev.2.3 _00 seiko instruments inc. 22 2. example of major power supply dependence characteristics (ta = 25 c) i ss vs. v in 023456 1400 1200 1000 800 600 400 200 0 i ss1 [ a] v in [v] 1 7 f osc = 1133 khz (r osc = 120 k ? ) f osc = 700 khz (r osc = 200 k ? ) f osc = 286 khz (r osc = 510 k ? ) i exth vs. v in i extl vs. v in 023456 ? 200 ? 180 ? 160 ? 140 ? 120 ? 100 ? 80 ? 60 ? 40 ? 20 0 i exth [ma] v in [v] 1 7 f osc = 700 khz, maxduty = 73% (r osc = 200 k ?, r duty = 300 k ? ) 023456 200 180 160 140 120 100 80 60 40 20 0 i extl [ma] v in [v] 1 7 f osc = 700 khz, maxduty = 73% (r osc = 200 k ?, r duty = 300 k ? ) i fb vs. v in f osc vs. v in 023456 0.10 0.08 0.06 0.04 0.02 0 ? 0.02 ? 0.04 ? 0.06 ? 0.08 ? 0.10 i fb [ a] v in [v] 1 7 023456 1400 1200 1000 800 600 400 200 0 f osc [khz] v in [v] 1 7 f osc = 1133 khz (r osc = 120 k ? ) f osc = 700 khz (r osc = 200 k ? ) f osc = 286 khz (r osc = 510 k ? ) maxduty vs. v in t ss vs. v in 023456 100 90 80 70 60 50 40 30 20 10 0 maxduty [%] v in [v] 1 7 maxduty = 88.5% (r osc = 200 k ?, r duty = 100 k ? ) maxduty = 73% (r osc = 200 k ?, r duty = 300 k ? ) maxduty = 47% (r osc = 200 k ?, r duty = 640 k ? ) 023456 25.0 20.0 15.0 10.0 5.0 0 t ss [ms] v in [v] 1 7 t ss = 20 ms t ss = 10 ms
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller rev.2.3 _00 s-8333 series seiko instruments inc. 23 t pro vs. v in i cch vs. v in 023456 70.0 60.0 50.0 40.0 30.0 20.0 10.0 0 t pro [ms] v in [v] 1 7 t pro =50 ms (csp = 0.1 f) 023456 ? 100 ? 90 ? 80 ? 70 ? 60 ? 50 ? 40 ? 30 ? 20 ? 10 0 i cch [ a] v in [v] 1 7 i ccl vs. v in 023456 100 90 80 70 60 50 40 30 20 10 0 i ccl [ a] v in [v] 1 7
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller s-8333 series rev.2.3 _00 seiko instruments inc. 24 3. example of external parts dependence characteristics f osc vs. r osc (v in = 3.3 v) 0 200 300 400 500 600 1600 1400 1200 1000 800 600 400 200 0 f osc [khz] r osc [k ? ] 100 ta = ? 40 c ta = 25 c ta = 85 c maxduty vs. r duty / r osc (r osc = 200 k ? , v in = 3.3 v) 0 1 1.5 2 2.5 3 100 90 80 70 60 50 40 30 20 10 0 maxduty [%] r duty / r osc 0.5 3.5 4.5 4 ta = ? 40 c ta = 25 c ta = 85 c t pro vs. csp (v in = 3.3 v) 0 0.2 0.3 0.4 0.5 350 300 250 200 150 100 50 0 t pro [ms] csp [ f] 0.1 ta = ? 40 c ta = 25 c ta = 85 c
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller rev.2.3 _00 s-8333 series seiko instruments inc. 25 4. examples of transient response characteristics 4.1 powering on (v out = 9.2 v, v in = 0 v 3.3 v, ta = 25 c) remark the switch (sw) is inserted between the diode (sd) and vout output. controlled externally to turn sw on a few ms later after the vin voltage is applied. (1) f osc = 1133 khz, i out = 0 ma, t ss = 10 ms (2) f osc = 1133 khz, i out = 100 ma, t ss = 10 ms ? 5 5 10 15 20 4 2 0 v in [v] time [ms] 0 12 8 4 0 v out [v] ? 5 5 10 15 20 4 2 0 v in [v] time [ms] 0 12 8 4 0 v out [v] (3) f osc = 700 khz, i out = 0 ma, t ss = 10 ms (4) f osc = 700 khz, i out = 100 ma, t ss = 10 ms ? 5 5 10 15 20 4 2 0 v in [v] time [ms] 0 12 8 4 0 v out [v] ? 5 5 10 15 20 4 2 0 v in [v] time [ms] 0 12 8 4 0 v out [v] ( 5) f osc = 286 khz, i out = 0 ma, t ss = 10 ms (6) f osc = 286 khz, i out = 100 ma, t ss = 10 ms ? 5 5 10 15 20 4 2 0 v in [v] time [ms] 0 12 8 4 0 v out [v] ? 5 5 10 15 20 4 2 0 v in [v] time [ms] 0 12 8 4 0 v out [v]
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller s-8333 series rev.2.3 _00 seiko instruments inc. 26 4.2 load fluctuations (v out = 9.2 v, v in = 3.3 v, ta = 25 c, r z = 200 k ? , c z = 0.01 f) (1) f osc = 1133 khz, i out = 0.1 ma 100 ma (2) f osc = 1133 khz, i out = 100 ma 0.1 ma ? 20 0 10 20 time [ms] ? 10 i out 100 ma 0.1 ma v out [0.2 v/div] 10.0 9.8 9.6 9.4 9.2 9.0 8.8 ? 20 0 10 20 time [ms] ? 10 i out 100 ma 0.1 ma v out [0.2 v/div] 10.0 9.8 9.6 9.4 9.2 9.0 8.8 (3) f osc = 700 khz, i out = 0.1 ma 100 ma (4) f osc = 700 khz, i out = 100 ma 0.1 ma ? 20 0 10 20 time [ms] ? 10 i out 100 ma 0.1 ma v out [0.2 v/div] 10.0 9.8 9.6 9.4 9.2 9.0 8.8 ? 20 0 10 20 time [ms] ? 10 i out 100 ma 0.1 ma v out [0.2 v/div] 10.0 9.8 9.6 9.4 9.2 9.0 8.8 (5) f osc = 286 khz, i out = 0.1 ma 100 ma (6) f osc = 286 khz, i out = 100 ma 0.1 ma ? 20 0 10 20 time [ms] ? 10 i out 100 ma 0.1 ma v out [0.2 v/div] 10.0 9.8 9.6 9.4 9.2 9.0 8.8 ? 20 0 10 20 time [ms] ? 10 i out 100 ma 0.1 ma v out [0.2 v/div] 10.0 9.8 9.6 9.4 9.2 9.0 8.8
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller rev.2.3 _00 s-8333 series seiko instruments inc. 27 4.3 input voltage fluctuations (v out = 9.2 v, i out = 100 ma, r z = 200 k ? , c z = 0.01 f) (1) f osc = 1133 khz, v in = 2.8 v 3.8 v (2) f osc = 1133 khz, v in = 3.8 v 2.8 v ? 20 0 10 20 time [ms] ? 10 v in [v] 4.0 3.5 3.0 2.5 v out [v] 9.40 9.30 9.20 9.10 ? 20 0 10 20 time [ms] ? 10 v in [v] 4.0 3.5 3.0 2.5 v out [v] 9.40 9.30 9.20 9.10 (3) f osc = 700 khz, v in = 2.8 v 3.8 v (4) f osc = 700 khz, v in = 3.8 v 2.8 v ? 20 0 10 20 time [ms] ? 10 v in [v] 4.0 3.5 3.0 2.5 v out [v] 9.40 9.30 9.20 9.10 ? 20 0 10 20 time [ms] ? 10 v in [v] 4.0 3.5 3.0 2.5 v out [v] 9.40 9.30 9.20 9.10 (5) f osc = 286 khz, v in = 2.8 v 3.8 v (6) f osc = 286 khz, v in = 3.8 v 2.8 v ? 20 0 10 20 time [ms] ? 10 v in [v] 4.0 3.5 3.0 2.5 v out [v] 9.40 9.30 9.20 9.10 ? 20 0 10 20 time [ms] ? 10 v in [v] 4.0 3.5 3.0 2.5 v out [v] 9.40 9.30 9.20 9.10
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller s-8333 series rev.2.3 _00 seiko instruments inc. 28 reference data 1. reference data for external parts table 6 properties of external parts element name product name manufacture characteristics inductor ldr655312t tdk corporation 10 h, dcr *1 = 307 m ? , i max *2 = 0.7 a, height = 1.2 mm diode rb491d rohm co., ltd. v f *3 = 0.45 v, i f *4 = 1.0 a output capacitor (ceramic) ? ? 16 v, 10 f transistor mch3406 sanyo electric co., ltd. v dss *5 = 20 v, v gss *6 = 10 v, c iss *7 = 280 pf, r ds(on) *8 = 82 m ? max. (v gs *9 = 2.5 v, i d *10 = 1 a) *1. dcr : dc resistance *2. i max : maximum allowable current *3. v f : forward voltage *4. i f : forward current *5. v dss : drain to source voltage (when short circuited between the gate and source) *6. v gss : gate to source voltage (when short circuited between the drain and source) *7. c iss : input capacitance *8. r ds(on) : drain to source on resistance *9. v gs : gate to source voltage *10. i d : drain current caution the values shown in the characteristics column of table 6 above are based on the materials provided by each manufacturer. however, consider the characteristics of the original materials when using the above products.
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller rev.2.3 _00 s-8333 series seiko instruments inc. 29 2. reference data (1) the data of (a) output current (i out ) vs. efficiency ( ) characteristics and (b) output current (i out ) vs. output voltage (v out ) characteristics is shown below. 2. 1 v out = 13.1 v (r fb1 = 7.5 k ? , r fb2 = 620 ? ) (1) f osc = 1133 khz, maxduty = 73% (r osc = 120 k ? , r duty = 180 k ? ) (a) i out vs. (b) i out vs. v out 0.01 1 10 100 1000 100 90 80 70 60 50 40 30 20 10 0 [%] i out [ma] 0.1 v in = 5.0 v 0.01 1 10 100 1000 13.20 13.15 13.10 13.05 13.00 12.95 12.90 v out [v] i out [ma] 0.1 v in = 5.0 v (2) f osc = 700 khz, maxduty = 73% (r osc = 200 k ? , r duty = 300 k ? ) (a) i out vs. (b) i out vs. v out 0.01 1 10 100 1000 100 90 80 70 60 50 40 30 20 10 0 [%] i out [ma] 0.1 v in = 5.0 v 0.01 1 10 100 1000 13.20 13.15 13.10 13.05 13.00 12.95 12.90 v out [v] i out [ma] 0.1 v in = 5.0 v (3) f osc = 286 khz, maxduty = 73% (r osc = 510 k ? , r duty = 750 k ? ) (a) i out vs. (b) i out vs. v out 0.01 1 10 100 1000 100 90 80 70 60 50 40 30 20 10 0 [%] i out [ma] 0.1 v in = 5.0 v 0.01 1 10 100 1000 13.20 13.15 13.10 13.05 13.00 12.95 12.90 v out [v] i out [ma] 0.1 v in = 5.0 v
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller s-8333 series rev.2.3 _00 seiko instruments inc. 30 2. 2 v out = 9.2 v (r fb1 = 8.2 k ? , r fb2 = 1.0 k ? ) (1) f osc = 1133 khz, maxduty = 73% (r osc = 120 k ? , r duty = 180 k ? ) (a) i out vs. (b) i out vs. v out 0.01 1 10 100 1000 100 90 80 70 60 50 40 30 20 10 0 [%] i out [ma] 0.1 v in = 5.0 v v in = 3.3 v 0.01 1 10 100 1000 9.30 9.25 9.20 9.15 9.10 9.05 9.00 v out [v] i out [ma] 0.1 v in = 5.0 v v in = 3.3 v (2) f osc = 700 khz, maxduty = 73% (r osc = 200 k ? , r duty = 300 k ? ) (a) i out vs. (b) i out vs. v out 0.01 1 10 100 1000 100 90 80 70 60 50 40 30 20 10 0 [%] i out [ma] 0.1 v in = 5.0 v v in = 3.3 v 0.01 1 10 100 1000 9.30 9.25 9.20 9.15 9.10 9.05 9.00 v out [v] i out [ma] 0.1 v in = 5.0 v v in = 3.3 v (3) f osc = 286 khz, maxduty = 73% (r osc = 510 k ? , r duty = 750 k ? ) (a) i out vs. (b) i out vs. v out 0.01 1 10 100 1000 100 90 80 70 60 50 40 30 20 10 0 [%] i out [ma] 0.1 v in = 5.0 v v in = 3.3 v 0.01 1 10 100 1000 9.30 9.25 9.20 9.15 9.10 9.05 9.00 v out [v] i out [ma] 0.1 v in = 5.0 v v in = 3.3 v
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller rev.2.3 _00 s-8333 series seiko instruments inc. 31 2. 3 v out = 6.1 v (r fb1 = 5.1 k ? , r fb2 = 1.0 k ? ) (1) f osc = 1133 khz, maxduty = 73% (r osc = 120 k ? , r duty = 180 k ? ) (a) i out vs. (b) i out vs. v out 0.01 1 10 100 1000 100 90 80 70 60 50 40 30 20 10 0 [%] i out [ma] 0.1 v in = 3.3 v v in = 2.5 v 0.01 1 10 100 1000 6.20 6.15 6.10 6.05 6.00 5.95 5.90 v out [v] i out [ma] 0.1 v in = 3.3 v v in = 2.5 v (2) f osc = 700 khz, maxduty = 73% (r osc = 200 k ? , r duty = 300 k ? ) (a) i out vs. (b) i out vs. v out 0.01 1 10 100 1000 100 90 80 70 60 50 40 30 20 10 0 [%] i out [ma] 0.1 v in = 3.3 v v in = 2.5 v 0.01 1 10 100 1000 6.20 6.15 6.10 6.05 6.00 5.95 5.90 v out [v] i out [ma] 0.1 v in = 3.3 v v in = 2.5 v (3) f osc = 286 khz, maxduty = 73% (r osc = 510 k ? , r duty = 750 k ? ) (a) i out vs. (b) i out vs. v out 0.01 1 10 100 1000 100 90 80 70 60 50 40 30 20 10 0 [%] i out [ma] 0.1 v in = 3.3 v v in = 2.5 v 0.01 1 10 100 1000 6.20 6.15 6.10 6.05 6.00 5.95 5.90 v out [v] i out [ma] 0.1 v in = 3.3 v v in = 2.5 v
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller s-8333 series rev.2.3 _00 seiko instruments inc. 32 3. reference data (2) the data of output current (i out ) vs. ripple voltage (vr) characteristics is shown below. 3. 1 v out = 13.1 v (r fb1 = 7.5 k ? , r fb2 = 620 ? ) (1) f osc = 1133 khz, maxduty = 73 % (r osc = 120 k ? , r duty = 180 k ? ) (2) f osc = 700 khz, maxduty = 73% (r osc = 200 k ? , r duty = 300 k ? ) 0.01 1 10 100 1000 100 90 80 70 60 50 40 30 20 10 0 vr [mv] i out [ma] 0.1 v in = 5.0 v 0.01 1 10 100 1000 100 90 80 70 60 50 40 30 20 10 0 vr [mv] i out [ma] 0.1 v in = 5.0 v (3) f osc = 286 khz, maxduty = 73% (r osc = 510 k ? , r duty = 750 k ? ) 0.01 1 10 100 1000 100 90 80 70 60 50 40 30 20 10 0 vr [mv] i out [ma] 0.1 v in = 5.0 v 3. 2 v out = 9.2 v (r fb1 = 8.2 k ? , r fb2 = 1.0 k ? ) (1) f osc = 1133 khz, maxduty = 73% (r osc = 120 k ? , r duty = 180 k ? ) (2) f osc = 700 khz, maxduty = 73% (r osc = 200 k ? , r duty = 300 k ? ) 0.01 1 10 100 1000 100 90 80 70 60 50 40 30 20 10 0 vr [mv] i out [ma] 0.1 v in = 5.0 v v in = 3.3 v 0.01 1 10 100 1000 100 90 80 70 60 50 40 30 20 10 0 vr [mv] i out [ma] 0.1 v in = 5.0 v v in = 3.3 v (3) f osc = 286 khz, maxduty = 73% (r osc = 510 k ? , r duty = 750 k ? ) 0.01 1 10 100 1000 100 90 80 70 60 50 40 30 20 10 0 vr [mv] i out [ma] 0.1 v in = 5.0 v v in = 3.3 v
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller rev.2.3 _00 s-8333 series seiko instruments inc. 33 3. 3 v out = 6.1 v (r fb1 = 5.1 k ? , r fb2 = 1.0 k ? ) (1) f osc = 1133 khz, maxduty = 73% (r osc = 120 k ? , r duty = 180 k ? ) (2) f osc = 700 khz, maxduty = 73% (r osc = 200 k ? , r duty = 300 k ? ) 0.01 1 10 100 1000 100 90 80 70 60 50 40 30 20 10 0 vr [mv] i out [ma] 0.1 v in = 3.3 v v in = 2.5 v 0.01 1 10 100 1000 100 90 80 70 60 50 40 30 20 10 0 vr [mv] i out [ma] 0.1 v in = 3.3 v v in = 2.5 v (3) f osc = 286 khz, maxduty = 73% (r osc = 510 k ? , r duty = 750 k ? ) 0.01 1 10 100 1000 100 90 80 70 60 50 40 30 20 10 0 vr [mv] i out [ma] 0.1 v in = 3.3 v v in = 2.5 v
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller s-8333 series rev.2.3 _00 seiko instruments inc. 34 marking specification (1) snt-8a (1) blank (2) to (4) product code (refer to product name vs. product code ) (5), (6) blank (7) to (11) lot number snt-8a top view 1 4 8 5 (9) (6) (2) (10) (7) (3) (11) (8) (4) (5) (1) product name vs. product code product code product code product name (2) (3) (4) product name (2) (3) (4) s-8333aaaa-i8t1g o f a s-8333abec-i8t1g o g o s-8333aaab-i8t1g o f b s-8333abfa-i8t1g o g p s-8333aaac-i8t1g o f c s-8333abfb-i8t1g o g q s-8333aaba-i8t1g o f d s-8333abfc-i8t1g o g r s-8333aabb-i8t1g o f e s-8333abga-i8t1g o g s s-8333aabc-i8t1g o f f s-8333abgb-i8t1g o g t s-8333aaca-i8t1g o f g s-8333abgc-i8t1g o g u s-8333aacb-i8t1g o f h s-8333abha-i8t1g o g v s-8333aacc-i8t1g o f i s-8333abhb-i8t1g o g w s-8333aada-i8t1g o f j s-8333abhc-i8t1g o g x s-8333aadb-i8t1g o f k s-8333abia-i8t1g o g y s-8333aadc-i8t1g o f l s-8333abib-i8t1g o g z s-8333aaea-i8t1g o f m s-8333abic-i8t1g o g 3 s-8333aaeb-i8t1g o f n s-8333acaa-i8t1g o h a s-8333aaec-i8t1g o f o s-8333acab-i8t1g o h b s-8333aafa-i8t1g o f p s-8333acac-i8t1g o h c s-8333aafb-i8t1g o f q s-8333acba-i8t1g o h d s-8333aafc-i8t1g o f r s-8333acbb-i8t1g o h e s-8333aaga-i8t1g o f s s-8333acbc-i8t1g o h f s-8333aagb-i8t1g o f t s-8333acca-i8t1g o h g s-8333aagc-i8t1g o f u s-8333accb-i8t1g o h h s-8333aaha-i8t1g o f v s-8333accc-i8t1g o h i s-8333aahb-i8t1g o f w s-8333acda-i8t1g o h j s-8333aahc-i8t1g o f x s-8333acdb-i8t1g o h k s-8333aaia-i8t1g o f y s-8333acdc-i8t1g o h l s-8333aaib-i8t1g o f z s-8333acea-i8t1g o h m s-8333aaic-i8t1g o f 3 s-8333aceb-i8t1g o h n s-8333abaa-i8t1g o g a s-8333acec-i8t1g o h o s-8333abab-i8t1g o g b s-8333acfa-i8t1g o h p s-8333abac-i8t1g o g c s-8333acfb-i8t1g o h q s-8333abba-i8t1g o g d s-8333acfc-i8t1g o h r s-8333abbb-i8t1g o g e s-8333acga-i8t1g o h s s-8333abbc-i8t1g o g f s-8333acgb-i8t1g o h t s-8333abca-i8t1g o g g s-8333acgc-i8t1g o h u s-8333abcb-i8t1g o g h s-8333acha-i8t1g o h v s-8333abcc-i8t1g o g i s-8333achb-i8t1g o h w s-8333abda-i8t1g o g j s-8333achc-i8t1g o h x s-8333abdb-i8t1g o g k s-8333acia-i8t1g o h y s-8333abdc-i8t1g o g l s-8333acib-i8t1g o h z s-8333abea-i8t1g o g m s-8333acic-i8t1g o h 3 s-8333abeb-i8t1g o g n
step-up, for lcd bias supply, 1-channel, pwm control switching regulator controller rev.2.3 _00 s-8333 series seiko instruments inc. 35 (2) 8-pin tssop (1) to (4) product name: 8333 (fixed) (5) to (8) function code (refer to product name vs. function code ) (9) to (14) lot number 8-pin tssop top view ( 1 ) ( 2 ) ( 3 ) ( 4 ) ( 5 ) ( 6 ) ( 7 ) ( 8 ) ( 11 ) ( 12 ) ( 13 ) ( 14 ) ( 9 ) ( 10 ) 1 4 8 5 product name vs. function code function code function code product name (5) (6) (7) (8) product name (5) (6) (7) (8) s-8333aaaa-t8t1g a a a a s-8333abec-t8t1g a b e c s-8333aaab-t8t1g a a a b s-8333abfa-t8t1g a b f a s-8333aaac-t8t1g a a a c s-8333abfb-t8t1g a b f b s-8333aaba-t8t1g a a b a s-8333abfc-t8t1g a b f c s-8333aabb-t8t1g a a b b s-8333abga-t8t1g a b g a s-8333aabc-t8t1g a a b c s-8333abgb-t8t1g a b g b s-8333aaca-t8t1g a a c a s-8333abgc-t8t1g a b g c s-8333aacb-t8t1g a a c b s-8333abha-t8t1g a b h a s-8333aacc-t8t1g a a c c s-8333abhb-t8t1g a b h b s-8333aada-t8t1g a a d a s-8333abhc-t8t1g a b h c s-8333aadb-t8t1g a a d b s-8333abia-t8t1g a b i a s-8333aadc-t8t1g a a d c s-8333abib-t8t1g a b i b s-8333aaea-t8t1g a a e a s-8333abic-t8t1g a b i c s-8333aaeb-t8t1g a a e b s-8333acaa-t8t1g a c a a s-8333aaec-t8t1g a a e c s-8333acab-t8t1g a c a b s-8333aafa-t8t1g a a f a s-8333acac-t8t1g a c a c s-8333aafb-t8t1g a a f b s-8333acba-t8t1g a c b a s-8333aafc-t8t1g a a f c s-8333acbb-t8t1g a c b b s-8333aaga-t8t1g a a g a s-8333acbc-t8t1g a c b c s-8333aagb-t8t1g a a g b s-8333acca-t8t1g a c c a s-8333aagc-t8t1g a a g c s-8333accb-t8t1g a c c b s-8333aaha-t8t1g a a h a s-8333accc-t8t1g a c c c s-8333aahb-t8t1g a a h b s-8333acda-t8t1g a c d a s-8333aahc-t8t1g a a h c s-8333acdb-t8t1g a c d b S-8333AAIA-T8T1G a a i a s-8333acdc-t8t1g a c d c s-8333aaib-t8t1g a a i b s-8333acea-t8t1g a c e a s-8333aaic-t8t1g a a i c s-8333aceb-t8t1g a c e b s-8333abaa-t8t1g a b a a s-8333acec-t8t1g a c e c s-8333abab-t8t1g a b a b s-8333acfa-t8t1g a c f a s-8333abac-t8t1g a b a c s-8333acfb-t8t1g a c f b s-8333abba-t8t1g a b b a s-8333acfc-t8t1g a c f c s-8333abbb-t8t1g a b b b s-8333acga-t8t1g a c g a s-8333abbc-t8t1g a b b c s-8333acgb-t8t1g a c g b s-8333abca-t8t1g a b c a s-8333acgc-t8t1g a c g c s-8333abcb-t8t1g a b c b s-8333acha-t8t1g a c h a s-8333abcc-t8t1g a b c c s-8333achb-t8t1g a c h b s-8333abda-t8t1g a b d a s-8333achc-t8t1g a c h c s-8333abdb-t8t1g a b d b s-8333acia-t8t1g a c i a s-8333abdc-t8t1g a b d c s-8333acib-t8t1g a c i b s-8333abea-t8t1g a b e a s-8333acic-t8t1g a c i c s-8333abeb-t8t1g a b e b

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the information described herein is subject to change without notice. seiko instruments inc. is not responsible for any problems caused by circuits or diagrams described herein whose related industrial properties, patents, or other rights belong to third parties. the application circuit examples explain typical applications of the products, and do not guarantee the success of any specific mass-production design. when the products described herein are regulated products subject to the wassenaar arrangement or other agreements, they may not be exported without authorization from the appropriate governmental authority. use of the information described herein for other purposes and/or reproduction or copying without the express permission of seiko instruments inc. is strictly prohibited. the products described herein cannot be used as part of any device or equipment affecting the human body, such as exercise equipment, medical equipment, security systems, gas equipment, or any apparatus installed in airplanes and other vehicles, without prior written permission of seiko instruments inc. although seiko instruments inc. exerts the greatest possible effort to ensure high quality and reliability, the failure or malfunction of semiconductor products may occur. the user of these products should therefore give thorough consideration to safety design, including redundancy, fire-prevention measures, and malfunction prevention, to prevent any accidents, fires, or community damage that may ensue.

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