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aat1275 boost converter with usb power switch 1275.2007.01.1.3 1 switchreg ? general description the aat1275 switchreg is a 2mhz, 500ma syn- chronous boost converter with an integrated current- limiting load switch controlled output. the aat1275 operates from a single-cell lithium-ion/ polymer bat- tery source and provides a regulated 5v, current limit controlled output to support usb port v bus applications in portable consumer electronic prod- ucts. the aat1275 can support both usb 2.0 host port and usb on-the-go operation, as well as gen- eral purpose applications where a 5v supply with a user programmable current limit is needed. the high efficiency boost converter section of the aat1275 is typically set for a 5v output and can deliver up to 500ma load current to support usb v bus operation from an input supply as low as 2.7v. the high boost converter switching frequen- cy (up to 2.0mhz) provides fast load transient and allows the use of small external components. fully integrated control circuitry simplifies system design and reduces total solution size. the integrated, programmable current limiting load switch provides usb port protection for portable devices allowing the aat1275 to supply a 5v usb v bus up to 500ma. the load switch provides an active low fault flag to alert the system in the event of an over-current condition applied to the aat1275 output. the aat1275 is available in the pb-free, space- saving 12-pin tsopjw and 16-pin tdfn34 pack- ages and is rated over the -40c to +85c operat- ing temperature range. features ? high frequency boost with 5v / 500ma output capability from a single-cell lithium- ion/polymer battery ? input voltage range: 2.7v to 5v ?v out1 adjustable or fixed (5v) ? >90% efficiency ? up to 2mhz switching frequency ? true load disconnect ? load switch with programmable current limit ? over-temperature, over-current protection ? inrush current limit ? fault report ? low shutdown current < 1a typical ? -40c to +85c temperature range ? tsopjw-12 and tdfn34-16 packages applications ? usb on-the-go ? cell phones ? digital still cameras ? pdas and portable media players ? smart phones ? other hand-held devices typical application aat1275 in out1 lin sw fb out2 gnd 10k vcc flt en set c in 4.7f c out1 4.7f c out2 1f r fb2 59k r set v in r fb1 432k l1 2.2h v bus outpu t enable fault
pin descriptions pin configuration tsopjw-12 tdfn34-16 (top view) (top view) pin # tsopjw-12 tdfn34-16 symbol function 1 1, 16 lin switched power input. connect an inductor between this pin and the sw pin. 2 3, 15 in supply input. 3 13, 14 pgnd power ground. 4 11, 12 sw switch pin. boost inductor is connected between sw and lin. 5 10 out1 boost converter output. 6 9 out2 load switch output. 7 8 set load switch current limit programming pin. connect a set resistor between this pin and ground. 8 7 flt load switch over-current or over-temperature fault flag. active low, open- drain output. a 10k external pull-up resistor is recommended. 9 6 fb boost converter voltage feedback pin. 10 5 gnd ground. 11 4 vcc bias supply for the internal circuitry. 12 2 en enable pin, active high. ep exposed paddle (bottom); connect to ground directly beneath the package. aat1275 boost converter with usb power switch 2 1275.2007.01.1.3 in vcc gnd lin en 3 fb flt set pgnd pgnd sw lin in sw out1 out2 4 5 1 2 6 7 8 14 13 12 16 15 11 10 9 1 2 3 4 5 6 12 11 10 9 8 7 lin in pgnd sw out1 out2 en vcc gnd fb flt set
absolute maximum ratings thermal characteristics 1 symbol description value units ja maximum thermal resistance tsopjw-12 110 c/w tdfn34-16 50 p d maximum power dissipation @ t a = 25c tsopjw-12 909 mw tdfn34-16 2.0 w symbol description value units vcc, in, out in, outx to gnd 6.0 v sw sw to gnd -0.3 to v out + 0.3 v lin, fb lin, fb to gnd -0.3 to v in + 0.3 v en, set, flt en, set, flt to gnd -0.3 to 6.0 v t j operating junction temperature range -40 to 150 c t lead maximum soldering temperature (at leads, 10 sec) 300 c aat1275 boost converter with usb power switch 1275.2007.01.1.3 3 1. mounted on a fr4 board.
electrical characteristics 1 v cc = v in = 3.6v, v out1 = 5v, t a = -40c to +85c, unless otherwise noted. typical values are at t a = 25c. symbol description conditions min typ max units v in, v cc operating input voltage range 2.7 5.0 v v outx maximum output voltage range 5.5 v v uvlo under-voltage lockout 2.7 v i q quiescent supply current no load, switching 100 a no load, not switching, v fb = 1.5v 45 90 i shdn shutdown current en = gnd 1.0 a boost converter i o continuous output current 3v < v in < 5v, v o = 5v 500 ma i limit input switch current limit 2.5 a v fb fb pin regulation no load, t a = 25c 0.591 0.6 0.609 v v out output voltage tolerance i load = 0 to 500ma, -3 3 % v in = 2.7v to 5v v out load regulation i load = 0 to 500ma 0.005 %/ma (v out * v in ) v out /v out line regulation v in = 2.7v to 5v 0.2 %/v r ds(on)h high side switch on resistance v out1 = 5v, i out1 = 500ma 200 m r ds(on)l low side switch on resistance v out1 = 5v, i out1 = 500ma 170 m r ds(on) _ in input disconnect switch v out1 = 5v, i out1 = 500ma 170 m t ss soft-start time from enable to output 300 s regulation efficiency i out1 = 250ma, l = 2.2h, 90 % v in = 3.6v, v out1 = 5v f osc switching frequency t a = 25c, i out1 = 500ma, 2.0 mhz v in = 3.6v, v out1 = 5v load switch r ds(on) current limit switch on resistance v out1 = 5v, t a = 25c 0.2 i lim current limit 500 625 ma i lim(min) minimum current limit 100 ma t resp current limit response time v out1 = 5v 0.4 s t on turn-on delay time v out1 = 5v, r l = 10 4ms t off turn-off delay time v out1 = 5v, r l = 10 10 s v flt _ low flt logic output low i sink = 1ma 0.4 v i flt flt logic output high leakage current v fault = 5v 0.5 1 a t blank fault blanking time rising and falling edge 4 ms control v th-l en threshold low 0.4 v v th-h en threshold high 1.4 v i en en input leakage v en = 5v, v in = 5v -1 1 a t j-th tj thermal shutdown threshold 140 c t j-hys tj thermal shutdown hysteresis 15 c aat1275 boost converter with usb power switch 4 1275.2007.01.1.3 1. the aat1275 is guaranteed to meet performance specifications over the -40c to +85c operating temperature range and is assu red by design, characterization, and correlation with statistical process controls.
typical characteristics aat1275 boost converter with usb power switch 1275.2007.01.1.3 5 no load current vs. temperature (v in = 3.6v; v out = 5.0v) temperature ( c) no load current (a) 0 20 40 60 80 100 120 140 -50 0 50 100 15 0 no load current vs. supply voltage supply voltage (v) no load current (a) 0 20 40 60 80 100 120 140 2.7 2.9 3.2 3.4 3.6 3.9 4.1 4.3 4.5 4.8 5. 0 -40 c 25 c 85 c output voltage vs. temperature (v in = 3.6v; 50 load) temperature ( c) output voltage (v) -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 -50 -25 0 25 50 75 100 line regulation (i out = 300ma) input voltage (v) output voltage accuracy (%) 4.940 4.942 4.944 4.946 4.948 4.950 4.952 4.954 4.956 4.958 4.960 3.6 3.7 3.8 3.9 4.0 4.1 4.2 dc regulation (v out = 5.0v) output current (ma) output error (%) -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 0.1 1 10 100 100 0 v in = 2.7v v in = 3.6v v in = 4.2v efficiency vs. load output current (ma) efficiency (%) 0 20 40 60 80 100 0.1 1 10 100 1000 v in = 2.7v v in = 3.6v v in = 4.2v
typical characteristics aat1275 boost converter with usb power switch 6 1275.2007.01.1.3 load switch r ds(on) vs. input voltage supply voltage (v) r ds(on) (m ) 0 50 100 150 200 250 2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 -40 c 25 c 85 c 120 c line transient response (16 load) time (100s/div) v in (500mv/div) v out (200mv/div) 3.6v 5.064v 4.752v 4.2v load transient response (v in = 3.6v; v out = 5.0v) time (100s/div) v out (50mv/div) i out (200ma/div) 5.0v 4.92v 500ma 250ma load transient response (v in = 3.6v; v out = 5.0v) time (100s/div) v out (100mv/div) i out (400ma/div) 5.062v 4.87v 500ma 1ma heavy load switching waveform (v in = 3.6v; v out = 5.0v; 500ma load) time (500ns/div) v out2 (100mv/div) i lx (500ma/div) v out1 (100mv/div) v lx (2v/div) light load switching waveform (v in = 3.6v; v out = 5.0v; 10ma load) time (5s/div) v out2 (25mv/div) i lx (500ma/div) v out1 (25mv/div) v lx (2v/div)
typical characteristics aat1275 boost converter with usb power switch 1275.2007.01.1.3 7 enable soft start (v in = 3.6v; 500ma load) time (1ms/div) en (2v/div) v out2 (2v/div) i in (500ma/div) v out1 (2v/div) n-channel r ds(on) vs. supply voltage supply voltage (v) r ds(on) (m ) 100 150 200 250 300 350 2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 25 c 85 c 100 c 125 c p-channel r ds(on) vs. supply voltage supply voltage (v) r ds(on) (m ) 160 180 200 220 240 260 280 300 320 2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4. 5 25 c 85 c 100 c 125 c shutdown (v in = 3.6v; c vout2 = 120f; 16 load) time (50ms/div) en (2v/div) v out2 (2v/div) v out1 (1v/div) enable soft start (v in = 3.6v; c vout2 = 120f; 16 load) time (100s/div) en (2v/div) v out2 (2v/div) v out1 (2v/div) enable soft start (v in = 4.2v; 500ma load) time (1ms/div) en (2v/div) v out2 (2v/div) i in (500ma/div) v out1 (2v/div)
typical characteristics aat1275 boost converter with usb power switch 8 1275.2007.01.1.3 switching frequency vs. temperature (v in = 3.6v; 16.5 load; l = 2.2h) temperature ( c) f s (khz) 820 840 860 880 900 920 940 -50 -25 0 25 50 75 100 switching frequency vs. input voltage (24w load; l = 2.2h) input voltage (v) f s (khz) 0 200 400 600 800 1000 3.0 3.2 3.4 3.6 3.8 4.0 4.2 current limit vs. temperature (r set = 20.3k ) temperature ( c) current limit (%) -6.0 -4.0 -2.0 0.0 2.0 4.0 6.0 -50 -25 0 25 50 75 10 0 current limit vs. r set current limit (ma) r set (k ) 10 100 10 100 1000
aat1275 boost converter with usb power switch 1275.2007.01.1.3 9 functional description the aat1275 is a 500ma synchronous boost con- verter with a current-limited load switch targeted for single-cell lithium-ion/polymer devices acting as a portable host for usb power. the aat1275 has integrated control and synchro- nous mosfets, minimizing the cost and the num- ber of external components. additional features include a soft-start function which allows the load voltage to ramp up in a controlled manner, elimi- nating output voltage overshoot and minimizing inrush current. typical soft-start time for the boost converter is approximately 300s. the aat1275 also has a load switch with user-pro- grammable current limiting. the load switch reports over-current and over-temperature conditions through an open-drain fault reporting signal (flt). the fault reporting signal has a 4ms turn-on delay. control scheme the control circuit uses hysteretic current mode control with internal inductor current sensing for very high efficiency over a wide output current range. for heavy load, the boost converter oper- ates in continuous conduction mode (ccm). this minimizes the rms current and optimizes the effi- ciency at load conditions where the losses are dominated by the power mosfet r ds(on) . this also keeps the ripple current to a minimum and minimizes the output voltage ripple and the output capacitor size. a zero current comparator senses the inductor current and prevents reverse current flow for optimum light load efficiency. functional block diagram boost regulator control load switch control flt set en vcc in out2 fb out1 sw lin gnd
aat1275 boost converter with usb power switch 10 1275.2007.01.1.3 step-up converter application information the aat1275 step-up converter provides the ben- efits of current mode control with a simple hys- teretic feedback loop. the device maintains excep- tional dc regulation, transient response, and cycle- by-cycle current limit without additional compensa- tion components. the aat1275 modulates the power mosfet switching current in response to changes in output voltage. the voltage loop pro- grams the required inductor current in response to changes in the output load and input voltage. the switching cycle initiates when the n-channel mosfet is turned on and the inductor current ramps up. the on interval is terminated when the inductor current reaches the programmed peak current level. during the off interval, the input cur- rent decays until the lower threshold, or zero induc- tor current is reached. the lower current is equal to the peak current minus a preset hysteresis thresh- old, which determines the inductor ripple current. the peak current is adjusted by the controller until the output current requirement is met. the magnitude of the feedback error signal deter- mines the average input current. therefore, the aat1275 boost controller implements a pro- grammed current source connected to the output capacitor and load resistor. there is no right-half plane zero, and loop stability is achieved with no additional external compensation components. at light load, the inductor off interval current goes to zero and the boost converter enters discontinu- ous mode operation. further reduction in the load results in a corresponding reduction in the switch- ing frequency, which reduces switching losses and maintains high efficiency at light loads. the operating frequency varies with changes in the input voltage, output voltage, and inductor size. once the boost converter has reached continuous mode, increasing the output load will not signifi- cantly change the operating frequency. a small 2.2h ( 20%) inductor is selected to maintain high frequency operation for the 5v usb output voltage. output voltage programming the output voltage is programmed through a resis- tor divider network located from the out1 output capacitor to the fb pin to ground. soft start / enable the input disconnect switch is activated when a valid input voltage is present and the en pin is pulled high. the slew rate control on the p-channel mosfet ensures minimal inrush current as the output voltage is charged to the input voltage prior to switching of the n-channel power mosfet. the soft-start circuitry guarantees monotonic turn-on and eliminates output voltage overshoot across the full input voltage range for all load conditions. current limit and over-temperature protection the switching of the n-channel mosfet termi- nates when current limit of 2.5a (typical) is exceed- ed. this minimizes the power dissipation and com- ponent stresses under overload and short-circuit conditions. switching resumes when the current decays below the limit. thermal protection disables the aat1275 boost converter when the internal power dissipation becomes excessive. the junction over-tempera- ture threshold is 140c with 15c of temperature hysteresis. the output voltage automatically recov- ers when the over-temperature or over-current fault condition is removed. under-voltage lockout under-voltage lockout (uvlo) guarantees suffi- cient v in bias and proper operation of all internal circuitry prior to soft start. internal bias of all circuits is controlled via the vcc input, which is connected to v in .
selecting the boost inductor the aat1275 boost controller utilizes hysteretic control and the switching frequency varies with out- put load and input voltage. the value of the induc- tor determines the maximum switching frequency of the boost converter. increasing output induc- tance decreases the switching frequency, resulting in higher peak currents and increased output volt- age ripple. to maintain the 2mhz switching fre- quency and stable operation, an output inductor sized from 1.5h to 2.7h is recommended. manufacturer's specifications list both the inductor dc current rating, which is a thermal limitation, and peak inductor current rating, which is a function of the saturation characteristics. measure the inductor current at full load and high ambient temperature to ensure that the inductor does not saturate or exhibit excessive temperature rise. select the output inductor (l) to avoid satura- tion at the minimum input voltage and maximum load. the rms current flowing through the boost inductor is equal to the dc plus ac ripple compo- nents. the maximum inductor rms current occurs at the minimum input voltage and the maximum load. use the following equations to calculate the maximum peak and rms current: at light load and low output voltage, the controller reduces the operating frequency to maintain maxi- mum efficiency. as a result, further reduction in out- put load does not reduce the peak current. the minimum peak current ranges from 0.5a to 0.75a. compare the rms current values with the manu- facturer's temperature rise, or thermal derating guidelines. for a given inductor type, smaller inductor size leads to an increase in dcr winding resistance and, in most cases, increased thermal impedance. winding resistance degrades boost converter efficiency and increases the inductor's operating temperature. shielded inductors provide decreased emi and may be required in noise sensitive applications. unshielded chip inductors provide significant space savings at a reduced cost compared to shielded inductors. in general, chip-type inductors have increased winding resistance (dcr) when com- pared to shielded, wound varieties. selecting the step-up converter capacitors the high output ripple inherent in the boost con- verter necessitates low impedance output filtering. multi-layer ceramic (mlc) capacitors provide small size, adequate capacitance, with low parasitic equivalent series resistance (esr) and equivalent series inductance (esl). this makes them well suited for use with the aat1275. mlc capacitors of type x7r or x5r ensure good capacitance stabili- ty over the full operating range. mlc capacitors exhibit significant capacitance reduction with an applied dc voltage. output ripple measurements can confirm that the capacitance used meets the specific ripple requirements. voltage derating mini- aat1275 boost converter with usb power switch 1275.2007.01.1.3 11 p loss(inductor) = i 2 rms dcr i rms = i pk 2 + i pk i v + i v 2 3 i v = i p - i pp i pp 2 i pk = i p + i o 1 - d i p = v in(min) d l f s i pp = v o - v in(min) v o d max =
aat1275 boost converter with usb power switch 12 1275.2007.01.1.3 mizes this factor, but results may vary with package size and among specific manufacturers. use a 4.7f 10v ceramic output capacitor to mini- mize output ripple for the 5v output. small 0805 sized ceramic capacitors are available which meet these requirements. estimate the output capacitor required at the min- imum switching frequency (f s ) of 800khz (worst- case). the boost converter input current flows during both on and off switching intervals. the input ripple current is less than the output ripple and, as a result, less input capacitance is required. a ceram- ic output capacitor from 1f to 4.7f is recom- mended. minimum 6.3v rated capacitors are required at the input. ceramic capacitors sized as small as 0603 are available which meet these requirements. setting the output voltage program the output voltage through a resistive divider located from the output to the fb pin to ground. the internal error amplifier reference volt- age is 0.6v. a 59.0k programming resistor value from vfb to gnd with a 432k resistor from fb to the output will set the output voltage to 5v. usb load switch application information setting the load switch current limit in most applications, the variation in i lim must be taken into account when determining r set . the i lim variation is due to processing variations from part to part, as well as variations in the voltages at out1 and out2, plus the operating temperature. the typical r set value for a 300ma load is in the range of 20 to 22k . operation in current limit when a heavy load is applied to out2 of the aat1275, the load current is limited to the value of i lim (determined by r set ) causing a drop in the output voltage. this increases the aat1275 power dissipation and die temperature. when the die tem- perature exceeds the over-temperature limit, the aat1275 shuts down until it has cooled sufficiently, at which point it will start up again. the aat1275 will continue to cycle on and off until the load is removed, power is removed, or until a logic low level is applied to the en pin. a fault flag indicates when the out2 pin load cur- rent has exceeded the current limit level set by r set . the fault flag is an active low, open-drain pin that requires 10k pull-up to v in . the fault signal has a 4ms blanking time to prevent false over cur- rent indicator during the charging of the usb bus capacitor. steady-state maximum power dissipation the maximum power dissipation for the aat1275 occurs at the minimum input voltage, where it oper- ates in continuous conduction mode (ccm). the total power dissipation at full load is dominated by the r ds(on) losses of the power mosfet. the dis- sipation includes the losses in the input and output switch, as well as both synchronous switches. v out = v ref 1 + r2 r3 = 0.6v 1 + = 5.0v 432k 59.0k i out d max f s v out c out =
due to the magnitude of the inductor ripple current, it cannot be neglected when analyzing the r ds(on) power dissipation. once the ripple current has been determined, the rms current during the on and the off period can be calculated. r ds(on)in is the input disconnect switch, r ds(on)n is the high-side synchronous switch, r ds(on)p is the low-side synchronous switch, and r ds(on) is the current limit load switch. pcb layout guidelines the step-up converter performance can be adversely affected by poor layout. possible impact includes high input and output voltage ripple, poor emi performance, and reduced operating efficiency. every attempt should be made to optimize the lay- out in order to minimize parasitic pcb effects (stray resistance, capacitance, inductance) and emi cou- pling from the high frequency sw node. a suggested pcb layout for the aat1275 is shown in figures 1 and 2. the following pcb layout guide- lines should be considered: 1. minimize the distance from capacitors c2 and c3 to the ic. this is especially true for the out- put capacitor c2, which conducts high ripple cur- rent associated with the step-up converter out- put capacitor. 2. place the feedback resistor close to the output terminals. route the output pin directly to resis- tor r2 to maintain good output regulation. r3 should be routed close to the output gnd pin and should not share a significant return path with output capacitor c2. 3. minimize the distance between l1 and the switching pin sw; minimize the size of the pcb area connected to the sw pin. 4. maintain a ground plane and connect to the ic rtn pin(s), as well as the gnd terminals of c1 and c2. aat1275 boost converter with usb power switch 1275.2007.01.1.3 13 v in(min) d max l f s i pp = v o - v in(min) v o d max = t j(max) = p total ja + t amb p total = i rms(on) 2 ( r ds(on)in + r ds(on)n ) + i rms(off) 2 ( r ds(on)in + r ds(on)p + r ds(on) ) i rms(off) = (i p 2 + i pk i v + i v 2 ) (1 - d max ) 3 i rms(on) = (i p 2 + i pk i v + i v 2 ) d max 3 i v = i p - i pp i pp 2 i pk = i p + i o 1 - d i p =
figure 1: aat1275 evaluation board figure 2: aat1275 evaluation board top side layout. bottom side layout. table 1: typical surface mount capacitors. table 2: typical surface mount inductors. inductance max dc dcr size (mm) manufacturer part number (h) current (a) ( ) lxwxh type sumida cdrh2d14-2r2 2.2 1.6 0.094 3.2x3.2x1.55 shielded sumida cdrh4d11/hp-2r4 2.4 1.7 0.105 4.8x4.8x1.2 shielded coiltronics sd3112-2r2 2.2 1.12 0.140 3.1x3.1x1.2 shielded coiltronics sd3114-2r2 2.2 1.48 0.086 3.1x3.1x1.4 shielded manufacturer part number value voltage temp. co. case murata grm21br61a475ka73l 4.7f 10v x5r 0805 murata grm18br60j475ke19d 4.7f 6.3v x5r 0603 murata grm21br60j106ke19 10f 6.3v x5r 0805 murata grm21br60j226me39 22f 6.3v x5r 0805 aat1275 boost converter with usb power switch 14 1275.2007.01.1.3
figure 3: aat1275 evaluation board schematic step-up converter design example specifications v out = 5v i out = 300ma v in = 2.7v to 4.2v (3.6v nominal) t amb = 50c output inductor from the characterization curves, the switching frequency at room temperature with a 300ma load and 2.2h inductor is about 800khz. aat1275 boost converter with usb power switch 1275.2007.01.1.3 15 v out - v in(min) v out d max = 5v - 2.7v 5v = = 0.46 lin 1 vin 2 pgnd 3 sw 4 out1 5 out2 6 set 7 flt 8 fb 9 gnd 10 vcc 11 en 12 aat1275 u1 432k r2 59k r3 10k r1 r4 16.9k l1 2.2h c2 4.7f 10v c3 4.7f 10v c6 120f ccase c1 4.7f flt v in gn d 1 2 3 enable v in v in v o2 v o1 j5 gnd gnd
for the sumida cdrh2d14-2r2 inductor, i sat = 1.0a, i dc(max) = 1.6a and dcr = 94m . 5v output capacitor aat1275 boost converter with usb power switch 16 1275.2007.01.1.3 i out d max f s v out c out(min) = 0.3a 0.46 800khz 0.05v = = 3.0f; use 4.7f 10v mlc v out = 0.05v p loss(inductor) = i 2 rms dcr = (590ma) 2 94m = 32mw i rms = i pk 2 + i pk i v + i v 2 3 = = 0.59a 0.9a 2 + 0.9a 0.2a + 0.2a 2 3 i v = i p - i pp = 0.9a - 0.7a = 0.20a i v = i p - i pp i pp 2 i pk = i p + i o 1 - d i p = v in(min) d max l f s i pp =
aat1275 losses aat1275 boost converter with usb power switch 1275.2007.01.1.3 17 t j(max) = p total ja + t amb = 0.22w + 85c = 109c 110c w p total = i rms(on) 2 ( r ds(on)in + r ds(on)n ) + i rms(off) 2 ( r ds(on)in + r ds(on)p + r ds(on) ) = 0.4a 2 ( 0.25 + 0.3 ) + 0.42 2 ( 0.25 + 0.3 + 0.2 ) = 0.22w i rms(off) = (i pk 2 + i pk i v + i v 2 ) (1 - d max ) 3 = = 0.43 a (0.9a 2 + 0.9a 0.2a + 0.2a 2 ) (1 - 0.46) 3 i rms(on) = (i pk 2 + i pk i v + i v 2 ) d max 3 = = 0.4 a (0.9a 2 + 0.9a 0.2a + 0.2a 2 ) 0.46 3
aat1275 boost converter with usb power switch 18 1275.2007.01.1.3 ordering information package information 3 tsopjw-12 all dimensions in millimeters. package marking 1 part number (tape and reel) 2 tsopjw-12 usxyy aat1275itp-5.0-t1 tdfn34-16 usxyy aat1275irn-5.0-t1 1. xyy = assembly and date code. 2. sample stock is generally held on part numbers listed in bold . 3. the leadless package family, which includes qfn, tqfn, dfn, tdfn and stdfn, has exposed copper (unplated) at the end of the lead terminals due to the manufacturing process. a solder fillet at the exposed copper edge cannot be guaranteed and is not re quired to ensure a proper bottom solder connection. 0.20 + 0.10 - 0.05 0.055 0.045 0.45 0.15 7 nom 4 4 3.00 0.10 2.40 0.10 2.85 0.20 0.50 bsc 0.50 bsc 0.50 bsc 0.50 bsc 0.50 bsc 0.15 0.05 0.9625 0.0375 1.00 + 0.10 - 0.065 0.04 ref 0.010 2.75 0.25 all analogictech products are offered in pb-free packaging. the term ?pb-free? means semiconductor products that are in compliance with current rohs standards, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. for more information, please visit our website at http://www.analogictech.com/pbfree.
aat1275 boost converter with usb power switch 1275.2007.01.1.3 19 tdfn34-16 all dimensions in millimeters. advanced analogic technologies, inc. 830 e. arques avenue, sunnyvale, ca 94085 phone (408) 737- 4600 fax (408) 737- 4611 ? advanced analogic technologies, inc. analogictech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an analogictech pr oduct. no circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. analogictech reserves the right to make changes to their products or specifi cations or to discontinue any product or service without notice. customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information b eing relied on is current and complete. all products are sold sub- ject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. analogictech warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with anal ogictech?s standard warranty. testing and other quality con- trol techniques are utilized to the extent analogictech deems necessary to support this warranty. specific testing of all param eters of each device is not necessarily performed. analogictech and the analogictech logo are trademarks of advanced analogic technologies incorporated. all other brand and produ ct names appearing in this document are regis- tered trademarks or trademarks of their respective holders. 3.00 0.05 0.05 0.05 0.229 0.051 (4x) 0.85 max 4.00 0.05 index area detail "a" top view bottom view side view 0.35 0.10 0.23 0.05 0.45 0.05 detail "a" pin 1 indicator (optional)

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Price & Availability of AAT1275IRN-50-T1

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