www.fairchildsemi.com rev. 1.1.2 12/18/00 features ? ultra low power consumption ? 150 mv dropout voltage at 150 ma ? 25 a ground current at 150 ma ? enable/shutdown control ? sot23-5 package ? thermal limiting ? 300 ma peak current applications ? cellular phones and accessories ?pdas ? portable cameras and video recorders ? laptop, notebook and palmtop computers description the fan2502/03 family of micropower low-dropout voltage regulators utilize cmos technology to offer a new level of cost-effective performance in gsm and tdma cellular handsets, laptop and notebook portable computers, and other portable devices. features include extremely low power consumption and low shutdown current, low dropout voltage, exceptional loop stability able to accommodate a wide variety of external capacitors, and the compact sot23-5 surface-mount package. the fan2502/03 family of products offer signi?cant improvements over older bicmos designs and are pin-compatible with many popular devices. the output is thermally protected against overload. the fan2502 and fan2503 devices are distinguished by the assignment of pin 4: fan2502: pin 4 C adj, allowing the user to adjust the output voltage over a wide range using an external voltage divider. fan2502-xx: pin 4 C byp, to which a bypass capacitor may be connected for optimal noise performance. output voltage is ?xed, indicated by the suf?x xx. fan2503-xx: pin 4 C err , a ?ag which indicates that the output voltage has dropped below the speci?ed minimum due to a fault condition. the standard ?xed output voltages available are 2.5v, 2.6v, 2.7v, 2.8v, 2.85v, 3.0v, and 3.3v. custom output voltage are also available: please contact your local fairchild sales of?ce for information. fan2502, fan2503 150 ma cmos ldo regulators block diagrams fan2502 en adj gnd thermal sense p v in v out bandgap error amplifier fan2502-xx en byp gnd gnd bandgap thermal sense p error amplifier v in v out fan2503-xx en err bandgap thermal sense p error amplifier v in v out
product specification fan2502/fan2503 2 rev. 1.1.2 12/18/00 pin assignments pin descriptions pin no. fan2502 fan2502-xx fan2503-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 fan2502 adjust. ratio of potential divider from vout to adj determines output voltage. byp 4 passive fan2502-xx bypass. connect 470 pf capacitor for noise reduction. err 4 open drain fan2503-xx error. error flag output. 0: output voltage < 95% of nominal. 1: output voltage > 95% of nominal. en 3 digital input enable. 0: shutdown v out . 1: enable v out . v in 1 power in voltage input. supply voltage input. v out 5 power out voltage output. regulated output voltage. gnd 2 power ground. 15 2 3 v in gnd en 4 v out adj/byp/err functional description designed utilizing cmos process technology, the fan2502/03 family of products are carefully optimized for use in compact battery-powered devices, offering a unique combination of low power consumption, extremely low dropout voltages, high tolerance for a variety of output capacitors, and the ability to disable the output to less than 1a under user control. in the circuit, a difference ampli?er controls the current through a series-pass p-channel mosfet, comparing the load voltage at the output with an onboard low-drift bandgap reference. the series resistance of the pass p-channel mosfet is approximately 1 ? , resulting in an unusually low dropout voltage under load when compared to older bipolar pass-transistor designs. protection circuitry is provided onboard for overload condi- tions. in conditions where the device reaches temperatures exceeding the speci?ed maximums, an onboard circuit shuts down the output, where it remains suspended until it has cooled before re-enabling. the user is also free to shut down the device using the enable control pin at any time. careful design of the output regulator ampli?er assures loop stability over a wide range of esr values in the external output capacitor. a wide range of values and types can be accomodated, allowing the user to select a capacitor meeting his space, cost, and performance requirements, and enjoy reliable operation over temperature, load, and tolerance variations.
fan2502/fan2503 product specification rev. 1.1.2 12/18/00 3 depending on the model selected, a number of control and status functions are available to enhance the operation of the ldo regulator. an enable pin, available on all devices, allows the user to shut down the regulator output to conserve power, reducing supply current to less than 1a. the adjustable-voltage versions of the device utilize pin 4 to connect to an external voltage divider which feeds back to the regulator error ampli?er, thereby setting the voltage as desired. two other functions are available at pin 4 in the ?xed-voltage versions: in noise-sensitive applications, an external bypass capacitor connection is provided that allows the user to achieve optimal noise performance at the output, while the error output functions as a diagnostic ?ag to indicate that the output voltage has dropped more than 5% below the nominal ?xed voltage. applications information external capacitors ?selection the fan2502/03 allows the user to utilize a wide variety of capacitors compared to other ldo products. an innovative design approach offers signi?cantly reduced sensitivity to esr (effective series resistance), which degrades regulator loop stability in older designs. while the improvements fea- tured in the fan2502/03 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, at a lower cost and a smaller case size than tantalums. those with x7r or y5vdielectric offer the best temperature coef?cient characteristics. the combination of tolerance and variation over temperature in some capacitor types can result in signif- icant variations, resulting in unstable performance over rated conditions. input capacitor an input capacitor of 2.2f (nominal value) or greater, connected between the input pin and ground, located in close proximity to the device, will improve transient response and noise rejection. higher values will offer supe- rior input 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 ?lm capacitor will give acceptable performance, however tanta- lum capacitors with a surge current rating appropriate to the application must be selected to avoid catastrophic failure. output capacitor an output capacitor is required to maintain regulator loop stability. unlike many other ldo regulators, the fan2502/ 03 family of products are nearly insensitve to output capaci- tor esr. stable operation will be achieved with a wide variety of capacitors with esr values ranging from 10m ? to 10 ? or more. tantalum or aluminum electrolytic, or multi- layer ceramic types can all be used. a nominal value of at least 1f is recommended. bypass capacitor (fan2502 only) in the ?xed-voltage con?guration, connecting a capacitor between the bypass pin and ground can signi?cantly reduce noise on the output. values ranging from 470pf to 10nf 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 circuit 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 ?lm types are recommended for their low leakage characteristics. cost-sensitive applications not concerned with noise can omit this capacitor. control functions enable pin applying a voltage of 0.4v or less at the enable pin will disable the output, reducing the quiescent output current to less than 1a, while a voltage of 2.0v or greater will enable the device. if this shutdown function is not needed, the pin can simply be connected to the v in pin. allowing this pin to ?oat will cause erratic operation. error flag (fan2503 only) to indicate conditions such as input voltage dropout (low v in ), overheating, or overloading (excessive output cur- rent), the err pin indicates a fault condition. it is an open- drain output which is high when the voltage at v out is greater than 95% of the nominal rated output voltage and low when v out is less than 95% or the rated output volt- age, as speci?ed in the error trip level characteristics. a logic pullup resistor of 100k ? is recommended at this output. the pin can be left disconnected if unused. thermal protection the fan2502/03 is designed to supply high peak output cur- rents of up to 1a for brief periods, however this output load will cause the device temperature to increase and exceed maximum ratings due to power dissipation. during output overload conditions, when the die temperature exceeds the shutdown limit temperature of 190c, onboard thermal protection will disable the output until the temperature drops below this limit, at which point the output is then re-enabled. during a thermal shutdown situation the user may assert the power-down function at the enable pin, reducing power consumption to the minimum level i gnd .
product specification fan2502/fan2503 4 rev. 1.1.2 12/18/00 thermal characteristics the fan2502/03 is designed to supply 150ma at the speci?ed output voltage with an operating die (junction) temperature of up to 125c. once the power dissipation and thermal resistance is known, the maximum junction temperature of the device can be calculated. while the power dissipation is calculated from known electrical parameters, the thermal resistance is a result of the thermal characteris- tics of the compact 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 125c, 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?ed at 130c /w, the ja of the minimum pwb footprint will be at least 235c /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 180c /w for one square inch to nearly 130c /w for 4 square inches. the addition of backside copper with through-holes, stiffeners, and other enhancements can also aid in reducing this value. the heat contributed by the dissipation of other devices located nearby must be included in design considerations. once the limiting parameters in these two relationships have been determined, the design can be modi?ed to ensure that the device remains within speci?ed 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. operation of adjustable version the adjustable version of the fan2502/03 includes an input pin adj which allows the user to select an output voltage ranging from 1.8v to near v in , using an external resistor divider. the voltage v adj presented to the adj pin is fed to the onboard error ampli?er which adjusts the output voltage until v adj is equal to the onboard bandgap reference voltage of 1.32v(typ). the equation is: the total value of the resistor chain should not exceed 250k ? total to keep the error ampli?er biased during no-load conditions. programming output voltages very near v in need to allow for the magnitude and variation of the dropout voltage v do over load, supply, and temperature variations. note that the low-leakage fet input to the cmos error ampli?er induces no bias current error to the calculation. general pwb layout considerations to achieve the full performance of the device, careful circuit layout and grounding technique must be observed. establish- ing a small local ground, to which the gnd pin, 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 optimal noise compensation from the onboard error ampli?er, especially during high load condi- tions. a large copper area in the local ground will provide the heat sinking discussed above when high power dissipation signi?cantly increases the temperature of the device. component-side copper provides signi?cantly better thermal performance for this surface-mount device, compared to that obtained when using only copper planes on the underside. p d v in v out C () i out v in i gnd + = p dmax () t jmax () t a C ja ------------------------------- ?? ?? ?? = v out 1.32v 1 r upper r lower --------------- - + =
fan2502/fan2503 product specification rev. 1.1.2 12/18/00 5 absolute maximum ratings (beyond which the device may be damaged) 1 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. applied voltage must be current limited to specified range. 3. based upon thermally limited junction temperature: 4. human body model is 4kv minimum using mil std. 883e, method 3015.7. machine model is 400v minimum using jedec method a115-a. operating conditions parameter min typ max unit power supply voltages v in (measured to gnd) 0 7 v enable input (en) applied voltage (measured to gnd) 2 07v err output applied voltage (measured to gnd) 2 07v power dissipation 3 internally limited temperature junction -65 150 ? lead soldering (5 seconds) 260 ? storage -65 150 ? electrostatic discharge 4 4kv parameter min nom max units v in input voltage 2.7 7.0 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 p d t jmax () t a C ja ------------------------------- =
product specification fan2502/fan2503 6 rev. 1.1.2 12/18/00 electrical characteristics notes: 1. unless otherwise stated, t a = 25?, v in = v out + 1v, i out = 100?, v ih > 2.0 v. 2. bold values indicate -40? t j 125?. 3. accuracy specified for fixed voltage versions only. adjustable version, has a bandgap voltage range of 1.24v to 1.40v with a nominal value of 1.32v. switching characteristics notes : 1. unless otherwise stated, t a = 25?, v in = v out + 1v, i out = 100?, v ih > 2.0 v. performance characteristics notes: 1. unless otherwise stated, t a = 25?, v in = v out + 1v, i out = 100?, v ih > 2.0 v. symbol parameter conditions min. typ. max. units regulator v do drop out voltage 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 150 180 mv ? v o 3 output voltage accuracy -2 2 % i gnd ground pin current i out = 150 ma 50 ? protection current limit thermally protected i gsd shut-down current en = 0v 1 a t sh thermal protection shutdown temperature 150 ? e tl err trip level fan2503 only 90 95 99 % enable input v il logic low voltage 0.8 0.4 v v ih logic high voltage 2.0 v i ih input current high 1 a i i input current low 1 a parameter conditions min. typ. max. unit enable input response time 3 msec. error flag (fan2503-xx) response time 3 msec. symbol parameter conditions min. typ. max. units ? v out / ? v in line regulation v in = (v out + 1) to 7v 0.3 % / v ? v out /v out load regulation i out = 0.1 to 150ma 1 2 % e n output noise 10hz?khz c out = 10?, c byp = 0.01? >10khz, c out = 10?, c byp = 0.01? <7 <0.01 psrr power supply rejection 120 hz, c out = 10?, c byp = 0.01? 43 db hz ?
fan2502/fan2503 product specification rev. 1.1.2 12/18/00 7 typical performance characteristics 0 20 40 60 80 100 psrr (db) frequency (hz) power supply frequency (hz) power supply rejection ratio i out = 100 a c out = 1.0 f cer. v in = 4.0v v out = 3.0v 10 100 1k 10k 100k 1m 10m 20 40 60 80 100 psrr (db) rejection ratio i out = 150ma c out = 1.0 f cer. 10 100 1k 10k 100k 1m 10m 0 10 20 30 40 50 60 70 3.0 3.6 4.1 psrr (db) voltage (v) rejection ratio vs. voltage drop power supply i out = 100 a 150ma c out = 1.0 f cer. 10ma 100ma 0 10 20 30 40 50 60 70 3.0 3.6 4.1 psrr (db) voltage (v) rejection ratio vs. voltage drop power supply i out = 100 a 150ma c out = 10 f cer. 10ma 100ma v in = 4.0v v out = 3.0v 0 frequency (hz) power supply rejection ratio 0 20 40 60 80 100 psrr (db) 10 i out = 10ma c out = 1.0 f cer. 100 1k 10k 100k 1m 10m v in = 4.0v v out = 3.0v frequency (hz) power supply rejection ratio 0 20 40 60 80 100 psrr (db) 10 i out = 100ma c out = 1.0 f cer. 100 1k 10k 100k 1m 10m v in = 4.0v v out = 3.0v frequency (hz) power supply rejection ratio 0 20 40 60 80 100 psrr (db) 10 i out = 100 a c out = 10 f cer. 100 1k 10k 100k 1m 10m v in = 4.0v v out = 3.0v frequency (hz) power supply rejection ratio 0 20 40 60 80 100 psrr (db) 10 i out = 10ma c out = 10 f cer. 100 1k 10k 100k 1m 10m v in = 4.0v v out = 3.0v 0 20 40 60 80 100 psrr (db) frequency (hz) frequency (hz) frequency (hz) power supply power supply noise performance rejection ratio i out = 100ma c out = 10 f cer. v in = 4.0v v out = 3.0v 10 100 1k 10k 100k 1m 10m 0 20 40 60 80 100 psrr (db) rejection ratio i out = 150ma c out = 10 f cer. 10 100 1k 10k 100k 1m 10m 0.0001 0.001 0.01 0.1 1 10 10 100 1k 10k 100k 1m v in = 4.0v v out = 3.0v c out = 1.0 f c byp = 0.01 f i l = 10 a v in = 4.0v v out = 3.0v noise ( v/ hz) load current (ma) ground pin current 15.00 17.00 19.00 21.00 23.00 25.00 0.1 1 10 100 v in = 4v v out = 3v quiescent current ( a)
product specification fan2502/fan2503 8 rev. 1.1.2 12/18/00 typical performance characteristics (continued) functional characteristics 0.00 temperature ( c) ground pin current 25 0 50 75 quiescent current ( a) -40 0 40 80 125 v in = 4v v out = 3v i l = 150ma output current (ma) dropout voltage 60.00 30.00 0.00 90.00 120.00 150.00 dropout voltage (mv) 0.1 25 50 75 100 125 150 temperature ( c) ground pin current 25 0 50 75 quiescent current ( a) -40 0 40 80 125 v in = 4v v out = 3v i l = 100 a input voltage (v) ground pin current 5.00 10.00 15.00 20.00 25.00 30.00 35.00 quiescent current ( a) 3.0 4.0 5.0 6.0 7.0 v out = 3v i out = 100 a 0.00 input voltage (v) ground pin current 5.00 10.00 15.00 20.00 25.00 30.00 35.00 quiescent current ( a) 3.0 4.0 5.0 6.0 7.0 v out = 3v i out = 150ma temperature ( c) -40 0 40 80 125 2 0 4 6 8 dropout voltage (mv) i l = 100 a input voltage (v) dropout characteristics dropout voltage temperature ( c) -40 0 40 80 125 50 0 100 150 200 dropout voltage (mv) i l = 150ma dropout voltage 1.0 0.5 0.0 1.5 2.0 2.5 3.0 3.5 output voltage (v) 0.0 1.0 2.0 3.0 4.0 5.0 v out = 3v r out = 20 ? r out = 30k ? temperature ( c) -40 0 40 80 125 output voltage vs. temperature 2.9 2.85 2.95 3 3.05 output voltage (v) v in = 4v typical 3v device i l = 100 a time (20 s/div) shutdown delay output voltage (1v/div) disable voltage (1v/div) disable v out time (20 s/div) enable pin delay output voltage (1v/div) enable voltage (1v/div) enable v out
fan2502/fan2503 product specification rev. 1.1.2 12/18/00 9 mechanical dimensions 5-lead sot-23-5 (s) package e b e1 d a1 a l c e h a .035 .057 symbol inches min. max. min. max. millimeters notes a1 .000 .006 .020 b .008 c .003 .010 e .059 .071 e h .087 .126 .037 bsc .075 bsc 0 10 e1 l d .106 .122 .90 1.45 .00 .15 .50 .20 .08 .25 1.50 1.80 2.20 3.20 .004 .024 .10 .60 .95 bsc 1.90 bsc 0 10 2.70 3.10 notes: 1. 2. 3. package outline exclusive of mold flash & metal burr. package outline exclusive of solder plating. eiaj ref number sc-74a.
product specification fan2502/fan2503 life support policy fairchild s 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 12/18/00 0.0m 005 stock#ds30002502 ? 2000 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. ordering information tape and reel information product number v out pin 4 function package marking fan2502s adj. adjust aea fan2502s25 2.5 bypass aee FAN2502S26 2.6 bypass aeg fan2502s27 2.7 bypass aej fan2502s28 2.8 bypass aem fan2502s285 2.85 bypass aen fan2502s30 3.0 bypass aew fan2502s33 3.3 bypass ae3 fan2503s25 2.5 error output afe fan2503s26 2.6 error output afg fan2503s27 2.7 error output afj fan2503s28 2.8 error output afm fan2503s285 2.85 error output afn fan2503s30 3.0 error output afw fan2503s33 3.3 error output af3 quantity reel size width 3000 7" 8mm
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