www.fairchildsemi.com rev. 1.0.2 8/26/03 features 70db ripple rejection ( >45db up to 1mhz) 150?ec power on time 150?ec enable time ? ow noise - 50?rms enable optimized for cdma time slices 180 mv dropout voltage at 150 ma enable/shutdown control enable time independent of noise bypass capacitor value ? o t23-5 package thermal limiting 300 ma trimmed current limit applications cellular phones and accessories ?das portable cameras and video recorders laptop, notebook and palmtop computers description the fan2534/fan2535 family of micropower low-dropout v oltage regulators utilize cmos technology to offer a new level of cost-effective performance in gsm, tdma, and cdma cellular handsets, laptop and notebook computers, and other portable devices. proprietary design technics ensure high ripple rejection. other features include low noise, short circuit current limit, thermal shutdown circuit, low dropout voltage, fast enable required in cdma handset applications, exceptional loop stability to accommodate a wide variety of external capacitors, and a compact sot23-5 surface-mount package. these products offer signi?ant improvements over older bipolar and cmos designs and are pin-compatible with many popular devices. the fan2534 and fan2535 devices are distinguished by the assignment of pin 4: f an2534: pin 4 ?adj, allowing the user to adjust the output voltage over a wide range using an external voltage divider. f an2534-xx: pin 4 ?byp, to which a bypass capacitor may be connected for optimal noise performance. output v oltage is ?ed, as speci?d by the suf? xx. f an2535-xx: pin 4 ?err , a ?g which indicates that the output voltage has dropped below the speci?d minimum due to a fault condition. the standard ?ed output voltages available are 2.6v, 2.85v, and 3.0v . custom output voltages are also available: please contact your local fairchild sales of?e for information. f an2534/fan2535 150 ma cmos ldo regulator with fast start, enable block diagrams fan2534 en adj gnd thermal sense p v in v out bandgap error amplifier fan2534-xx en byp gnd gnd bandgap thermal sense p error amplifier v in v out fan2535-xx en err bandgap thermal sense p error amplifier v in v out
2 rev. 1.0.2 8/26/03 fan2534/fan2535 product specification pin assignments pin descriptions absolute maximum ratings (note 1) pin no. fan2534 fan2534-xx fan2535-xx 1. v in v in v in 2. gnd gnd gnd 3. en en en 4. adj byp err 5. v out v out v out pin name pin no. type pin function description adj 4 input fan2534 adjust. ratio of potential divider from vout to adj determines output voltage. byp 4 passive fan2534-xx bypass. connect 10 nf capacitor for noise reduction. err 4 open drain fan2535-xx error. error flag output. low when vout< 95% of nominal; high when vout> 95% of nominal. en 3 digital input enable. low in shutdown mode; high in enable mode v in 1 power in voltage input. supply voltage input. v out 5 power out voltage output. regulated output voltage. gnd 2 power ground. p arameter min. typ. max. unit po wer supply voltages v in (measured to gnd); enable input (en); err output; 07v power dissipation internally limited operating junction temperature -65 150 ? lead soldering (5 seconds) 260 ? storage -65 150 ? electrostatic discharge (note 2) 4 kv 5 3 fb shdn cap+ cap- gnd v in v out en adj/byp/err 1 4 2
rev. 1.0.2 8/26/03 3 product specification fan2534/fan2535 operating conditions dc electrical characteristics (notes 4, 5) symbol parameter min. typ. max. units v in input voltage range v out + v do 6.5 v v out output voltage range fan2534-xx, fan2535-xx (note 3) 2.3 3.3 v v out output voltage range (fan2534 only) 2.0 5.0 v v en enable input voltage 0 v in v v err err flag voltage v in v t j junction temperature -40 +125 ? ja thermal resistance 220 ?/w jc thermal resistance 130 ?/w symbol parameter conditions min. typ. max. units regulator v do drop out voltage (note 6) i out = 100 ? 2.5 4 mv i out = 50 ma 50 75 mv i out = 100 ma 100 140 mv i out = 150 ma 180 220 mv ? v o output voltage accuracy (note 7) initial accuracy at no load -1 1 % over line, load & temp -3.7 2 % i gnd(nl) ground pin current no load 90 ? i gnd(fl) ground pin current i out = 150 ma 110 ? protection current limit 300 400 ma i gsd shut-down current en = 0v 1 ? t sh thermal shutdown temperature hysteresis 155 15 ? ? e tl err trip level fan2535 only 90 93 96 % enable input v el logic low voltage 0.4 1.2 v v eh logic high voltage 1.4 2 v i eh input current high 1 a i el input current low 1 a
4 rev. 1.0.2 8/26/03 fan2534/fan2535 product specification switching characteristics (notes 4, 5) ac performance characteristics (notes 4, 5) notes: 1. functional operation under any of these conditions is not implied. performance and reliability are guaranteed only if operating conditions are not exceeded. 2. using mil std. 883e, method 3015.7(human body model), 400v when using jedec method a115-a (machine model). 3. for specific output voltages of the fixed oputput voltage versions please refer to the table: "output voltage options and ordering information" on page 9. custom fixed output voltages, not listed in the table, are also available. 4. unless otherwise stated, t a = 25?, v in = v out + 1v, i out = 100?, v eh > 2.0 v. 5. bold values indicate -40 0.5hz. p arameter conditions min. typ. max. unit enable response time (note 8) c l =10? c bp =10nf 150 300 ?ec power "on" response time c l =10uf c bp =10nf v out = 3.0v 150 500 ?ec error flag response time (fan2535-xx only) 3 msec symbol parameter conditions min. typ. max. units ? v out / ? v in line regulation v in = (v out + 1) to 6.5v, i l = 10ma 0.05 0.2 % / v ? v out / v out load regulation i out = 0.1 to 100ma 1.0 2.0 % e n output noise bw: 300hz?0khz c out = 10?, c byp = 0.01? 50 ? rms psrr power supply ripple rejection 100 hz, c out = 1?, c byp = 0.01? 0ma rev. 1.0.2 8/26/03 5 product specification fan2534/fan2535 functional description utilizing cmos technology, the fan2534/fan2535 product family is optimized for use in compact battery powered systems, offering a unique combination of high ripple rejection, low noise, low power consumption, e xtremely low dropout voltages, high tolerance for a variety of output capacitors, and less than 1? "off" current. in the circuit, a differential ampli?r controls a series-pass p-channel mosfet, and a separate error ampli?r com- pares the load voltage at the output with an onboard trimmed low voltage bandgap reference. the series resistance of the pass p-channel mosfet is approximately 1 ohm, yielding an unusually low dropout voltage even under high load conditions. thermal shutdown and current limit circuits protect the device under extreme conditions. when the device tempera- ture reaches 155?, the output is disabled, until the device cooles down by 15?, then re-enabled. the user can to shut down the device using the enable control pin at any time. the current limit circuit is trimmed, which leads to consis- tent power on /enable delays, and provides safe short circuit current densities even in narrow traces of the pcb. a carefully optimized control loop accommodates a wide range of esr values in the output bypass capacitor, allowing the user to optimize space, cost, and performance require- ments. an enable pin shuts down the regulator output to conserve power, reducing supply current to less than 1?. the output can then be re-enabled within 150?ec, ful?ling the fast power-cycling needs of cdma applications. depending on the device type selected, other control and status functions are available at pin 4. the ?ed-voltage v ersions are available with either a noise-bypass pin or an error ?g pin option. the error ?g can be used as a diagnos- tic function to indicate that the output voltage has dropped more than 5% below the nominal value. the adjustable-voltage versions utilize pin 4 to connect to an e xternal voltage divider which feeds back to the regulator error ampli?r, thus setting the output voltage to the desired v alue. applications information external capacitors ?selection the fan2534/fan2535 allows the user to utilize a wide v ariety of capacitors compared to other ldo products. an innovative design approach offers signi?antly reduced sensitivity to esr (equivalent series resistance), which degrades regulator loop stability in older designs. while the improvements featured in the fan2534/fan2535 family greatly simplify the design task, capacitor quality still must be considered if the designer is to achieve optimal circuit performance. in general, ceramic capacitors offer superior esr performance, and a smaller case size than tantalums. input capacitor an input capacitor of 2.2? (nominal value) or greater, connected between the input pin and ground, placed in close proximity to the device, will improve transient response and ripple rejection. higher values will further improve ripple rejection and transient response. an input capacitor is recommended when the input source, either a battery or a regulated ac voltage, is located far from the device. any good quality ceramic, tantalum, or metal ?m capacitor will give acceptable performance, however in extreme cases capacitor surge current ratings may have to be considered. output capacitor an output capacitor is required to maintain regulator loop stability. stable operation will be achieved with a wide v ariety of capacitors with esr values ranging from 0m ? up to 400m ? . multilayer ceramic, tantalum or aluminum electrolytic capacitors may be used. a nominal value of at least 1? is recommended. note that the choice of output capacitor effects load transient response, ripple rejection, and it has a slight effect on noise performance as well. bypass capacitor (fan2534-xx only) in the ?ed-voltage con?uration, connecting a capacitor between the bypass pin and ground can signi?antly reduce output noise. values ranging from 0pf to 47nf can be used, depending on the sensitivity to output noise in the application. at the high-impedance bypass pin, care must be taken in the pcb layout to minimize noise pickup, and capacitors must be selected to minimize current loading (leakage). noise pickup from external sources can be considerable. leakage currents into the bypass pin will directly affect regulator accuracy and should be kept as low as possible; thus, high- quality ceramic and ?m types are recommended for their low leakage characteristics. cost-sensitive applications not concerned with noise can omit this capacitor.
fan2534/fan2535 product specification 6 rev. 1.0.2 8/26/03 control functions enable pin connecting 2.0v or greater to the enable pin will enable the output, while 0.4v or less will disable it while reducing the quiescent current consumption to less than 1?. if this shutdown function is not needed, the pin can simply be connected permanently to the v in pin. allowing this pin to ?at will cause erratic operation. error flag (fan2535-xx only) f ault conditions such as input voltage dropout (low v in ), overheating, or overloading (excessive output current), will set an error ?g: the err pin which is an open-drain output, will go low when v out is less than 95% or the speci?d output voltage. when the voltage at v out is greater than 95% of the speci?d output voltage, the err pin is high. a logic pullup resistor of 100k ohm is recommended at this output. the pin can be left discon- nected if unused. thermal protection the fan2534/fan2535 is designed to supply high peak output currents for brief periods, however sustained exces- sive output load at high input - output voltage difference will cause the device temperature to increase and exceed maximum ratings due to power dissipation. during output ov erload conditions, when the die temperature exceeds the shutdown limit temperature of 155?, an onboard thermal protection will disable the output until the temperature drops approximately 15? below the limit, at which point the output is re-enabled. during a thermal shutdown situation the user may assert the power-down function at the enable pin, reducing power consumption to a minimum. thermal characteristics the fan2534/fan2535 is designed to supply 150ma at the speci?d output voltage with an operating die (junction) temperature of up to 125?. once the power dissipation and thermal resistance is known, the maximum junction tempera- ture of the device can be calculated. while the power dissipa- tion is calculated from known electrical parameters, the actual thermal resistance depends on the thermal characteris- tics of the sot23-5 surface-mount package and the surrounding pc board copper to which it is mounted. the power dissipation is equal to the product of the input-to- output voltage differential and the output current plus the ground current multiplied by the input voltage, or: the ground pin current i gnd can be found in the charts provided in the electrical characteristics section. the relationship describing the thermal behavior of the package is: where t j(max) is the maximum allowable junction tempera- ture of the die, which is 125?, and t a is the ambient operat- ing temperature. ja is dependent on the surrounding pc board layout and can be empirically obtained. while the jc (junction-to-case) of the sot23-5 package is speci?d at 130? /w, the ja of the minimum pwb footprint will be at least 235? /w. this can be improved upon by providing a heat sink of surrounding copper ground on the pwb. depending on the size of the copper area, the resulting ja can range from approximately 180? /w for one square inch to nearly 130? /w for 4 square inches. the addition of backside copper with through-holes, stiffeners, and other enhancements can also aid in reducing thermal resistance. the heat contributed by the dissipation of other devices located nearby must be included in the design consider- ations. once the limiting parameters in these two relation- ships have been determined, the design can be modi?d to ensure that the device remains within speci?d operating conditions. if overload conditions are not considered, it is possible for the device to enter a thermal cycling loop, in which the circuit enters a shutdown condition, cools, re- enables, and then again overheats and shuts down repeatedly due to an unmanaged fault condition. adjustable version the fan2534 adjustable version includes an input pin adj which allows the user to select an output voltage ranging from 2.5v to near v in , using an external resistor divider. the v oltage v adj presented to the adj pin is fed to the onboard error ampli?r which adjusts the output voltage until v adj is equal to the onboard bandgap reference voltage of 1.00v(typ). the equation is: since the bandgap reference voltage is trimmed, 1% initial accuracy can be achieved. the total value of the resistor chain should not exceed 250k ohm total to keep the error ampli?r biased during no-load conditions. programming output voltages very near v in need to allow for the magni- tude and variation of the dropout voltage v do over load, supply, and temperature variations. note that the low-leak- age fet input to the cmos error ampli?r induces no bias current error to the calculation. p d v in v out () i out v in i gnd + = p d max () t j max () t a ja ------------------------------- ?? ?? ?? = v out 1.00v 1 r upper r lower --------------- - + =
rev. 1.0.2 8/26/03 7 product specification fan2534/fan2535 general pwb layout considerations f or optimum device performance, careful circuit layout and grounding technics must be used. establishing a small local ground, to which the gnd pin, and the output and bypass capacitors are connected, is recommended, while the input capacitor should be grounded to the main ground plane. the quiet local ground is then routed back to the main ground plane using feedthrough vias. in general, the high- frequency compensation components (input, bypass, and output capacitors) should be located as close to the device as possible. the proximity of the output capacitor is especially important to achieve optimum performance, especially during high load conditions. a large copper area in the local ground serves as heat sink (as discussed above) when high power dissipation signi?antly increases device temperature. component-side copper provides signi?antly better thermal performance. added feedthrough connecting the device side ground plane to the back plane further reduces thermal resistance.
8 rev. 1.0.2 8/26/03 fan2534/fan2535 product specification t ypical performance characteristics enable delay disable delay po wer on delay ground current vs ambient temperature ripple rejection plot c out = 3.3 f, c byp = 10nf i load = 150ma c out = 3.3 f, c byp = 10nf i load = 150ma c out = 3.3 f, c byp = 10nf, i load = 150ma enable delay = 152 sec v en v out v en v out v in v out c out = 3.3 f, c byp = 10nf, i load = 150ma disable delay = 214 sec c out = 3.3 f, c byp = 10nf, i load = 150ma power on delay = 150 sec ambient temperature (?) -40 -20 0 20 40 60 80 100 120 ground current ( a) 70 80 90 100 110 i load = 0ma 1.8 v 1.6 v 1.4 v 1.2 v 1 v 400nv 600nv 800nv 200nv noise plot -30 db -35 -40 -45 -50 -55 -60 -65 -70 -75 -80
rev. 1.0.2 8/26/03 9 product specification fan2534/fan2535 t ypical performance characteristics (continued) v out variation vs ambient temperature dropout voltage vs ambient temperature dropout voltage vs load current v out variation (%) droupout voltage (mv) droupout voltage (mv) 120 140 160 180 200 220 240 0 20 40 60 80 100 120 140 160 0.6 0.4 0.2 0.0 -0.2 -0.4 -0.6 -0.8 -25 0 -40 -20 0 20 40 60 25 ambient temperature ( c) load current (ma) ambient temperature ( c) 50 75 0255075 100 125 150 i load = 150ma i load = 150ma t = 25 c
10 rev. 1.0.2 8/26/03 fan2534/fan2535 product specification d e1 e b e h a a1 l c mechanical dimensions 5-lead sot-23 package symbol inches millimeters notes min max min max a .035 .057 .90 1.45 a1 .000 .006 .00 .15 b .008 .020 .20 .50 c .003 .010 .08 .25 d .106 .122 2.70 3.10 e .059 .071 1.50 1.80 e .037 bsc .95 bsc e1 .075 bsc 1.90 bsc h .087 .126 2.20 3.20 l .004 .024 .10 .60 0 10 0 10
product specification fan2534/fan2535 life support policy fairchild? products are not authorized for use as critical components in life support devices or systems without the express written approval of the president of fairchild semiconductor corporation. as used herein: 1. life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user. 2. a critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. www.fairchildsemi.com 8/26/03 0.0m 004 stock#ds30002591 ? 2002 fairchild semiconductor corporation disclaimer fairchild semiconductor reserves the right to make changes without further notice to any products herein to improve reliability, function or design. fairchild does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights, nor the rights of others. output voltage options and ordering information t ape and reel information product number v out pin 4 function package marking fan2534sx adj. adjust aja fan2534s26x 2.6 bypass ajg fan2534s30x 3.0 bypass ajw FAN2535S26X 2.6 error output akg fan2535s285x 2.85 error output akn quantity reel size width 3000 7" 8mm
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