L4925 very low drop voltage regulator operating dc supply voltage range 6v to 28v transient supply voltage up to 40v extremely low quiescent current high precision output voltage output current capability up to 500ma very low dropout voltage less than 0.6v reset circuit sensing the output voltage programmable reset pulse delay with external capacitor thermal shutdown and short cir- cuit protections description the L4925 is a monolithic integrated 5v voltage regulator with a very low dropout output and addi- tional functions such as power-on reset and pro- grammable reset delay time. it is designed for supplying microcomputer controlled systems es- pecially in automotive applications. this is advanced information on a new product now in development or undergoing evaluation. details are subject to change withou t notice. june 2000 ? + - preregulator 5v vref 1.23v vz vz 2 m = v s gnd 2v reset reg L4925n v o ct res d95at151 c s block diagram ordering numbers: L4925 (pentawatt) L4925pd (powerso20) pentawatt powerso20 1/8
connection diagram absolute maximum ratings symbol parameter value unit v sdc dc operating supply voltage 28 v v str transient supply voltage (t < 1s) 40 v i o output current internally limited v o output voltage 20 v v res output voltage 20 v i res output current 5 ma t stg storage temperature -55 to 150 c t j operating junction temperature -40 to 150 c t j-sd thermal shutdown-junction temperature 165 c note: the circuit is esd protected according to mil-std-883c. according to iso/dis 7637 the transients must be clamped with external circuitry (see application circuit). thermal data symbol parameter pentawatt so 20 unit r th j-amb r th j-case thermal resistance junction to ambient max. thermal resistance junction to case max. 60 3.5 77 to 97 c/w c/w n.c. n.c. v s v s n.c. res n.c. n.c. n.c. n.c. n.c. ct vout n.c. vout n.c. n.c. n.c. 1 3 2 4 5 6 7 8 9 18 17 16 15 14 12 13 11 19 10 20 gnd n.c. d95at152 L4925 2/8
electrical characteristics (v s =14v t j =C40 to 125 c unless otherwise specified; symbol parameter test condition min. typ. max. unit v o output voltage v i = 6 to 28v; i o = 1 to 500ma 4.90 5 5.10 v v o output voltage v i = 35v; t <1s; i o = 1 to 500ma 5.50 v v dp dropout voltage i o = 100ma i o = 500ma 0.2 0.3 0.3 0.6 v v v io input to output voltage difference in undervoltage condition v i = 4v; i o = 100ma 0.5 v v ol line regulation v i = 6 to 28v; i o = 1 to 1ma 10 mv v olo load regulation i o = 1 to 500ma 50 mv i lim current limit v o = 4.5v ; v o = 0; foldback characteristic 550 1000 250 1500 ma ma i qse quiescent current i o = 0.3ma 190 360 m a i q quiescent current i o = 500ma 20 ma reset symbol parameter test condition min. typ. max. unit v rt reset threshold voltage 4.5 5.2 v v rth reset threshold 50 100 200 mv t rd reset pulse delay c t = 100nf; t r > 100 m s 60 100 140 ms t rr reset reaction time c t = 100nf; 5 30 m s v rl reset output low voltage r res = 10k w to v o ; v s = > 3v 0.4 v i rh reset output high leakage current v res = 5v 1 m a v ctth delay comparator threshold 2 v v ctth hy delay comparator threshold hysteresis 200 mv + - preregulator 5v vref 1.23v vz vz 2 m = v s gnd 2v reset reg L4925n vo ct res d95at153 vbat c s co vout res application circuit diagram for stability: c s > 1 m f; c o > 10 m f;esr < 2.5 w at 10 khz recommended for application: c s =c o = 10 m f to 100 m f L4925 3/8
application note supply voltage transients high supply voltage transients can cause a reset output signal disturbation. for supply voltage greater than 8v the circuit shows a high immunity of the reset output against supply transients of more than 100v/ m s. for supply voltage lower than 8v, supply tran- sients of more than 0.4v/ m s. can cause a reset signal disturbation. foldback characteristics of vo functional description the L4925 is a monolithic integrated voltage regulator, based on the stm modular voltage regulator approach. several outstanding features and auxiliary functions are implemented to meet the requirements of supplying microprocessor systems in automotive applications. nevetrheless, it is suitable also in other applica- tions where the present functions are required. the modular approach of this device allows to get easily also other features and functions when re- quired. voltage regulator the voltage regulator uses an isolated collector vertical pnp transistor as a regulating element. with this structure very low dropout voltage at currents up to 500ma is obtained. the dropout operation of the standby regulator is maintained down to 3v input supply voltage. the output voltage is regulated up to the transient in- put supply voltage of 35v. with this feature no functional interruption due to overvoltage pulses is generated. the typical curve showing the standby output voltage as a function of the input supply voltage is shown in fig. 1. the current consumption of the device (quiescent current) is less than 250 m a. to reduce the quiescent current peak in the un- dervoltage region and to improve the transient re- sponse in this region, the dropout voltage is con- trolled. the quiescent current as a function of the supply input voltage is shown in fig. 2. figure 1: output voltage vs. input voltage figure 2: quiescent current vs. supply voltage L4925 4/8
reset circuit the block circuit diagram of the reset circuit is shown in figure 3. the reset circuit supervises the output voltage. the reset threshold of 4.5v is defined with the internal reference voltage and standby output divider. the reset pulse delay time t rd , is defined with the charge time of an external capacitor c t : t rd = c t x 2v 2 m a the reaction time of the reset circuit originates from the discharge time limitation of the reset ca- pacitor c t and it is proportional to the value of c t . the reaction time of the reset circuit increases the noise immunity.standby output voltage drops be- low the reset threshold only a bit longer than the reaction time results in a shorter reset delay time. the nominal reset delay time will be generated for standby output voltage drops longer than approxi- mately 50 m s. the typical reset output waveforms are shown in figure 4. figure 3 figure 4 L4925 5/8
pentawatt v dim. mm inch min. typ. max. min. typ. max. a 4.8 0.189 c 1.37 0.054 d 2.4 2.8 0.094 0.110 d1 1.2 1.35 0.047 0.053 e 0.35 0.55 0.014 0.022 e1 0.76 1.19 0.030 0.047 f 0.8 1.05 0.031 0.041 f1 1 1.4 0.039 0.055 g 3.2 3.4 3.6 0.126 0.134 0.142 g1 6.6 6.8 7 0.260 0.268 0.276 h2 10.4 0.409 h3 10.05 10.4 0.396 0.409 l 17.55 17.85 18.15 0.691 0.703 0.715 l1 15.55 15.75 15.95 0.612 0.620 0.628 l2 21.2 21.4 21.6 0.831 0.843 0.850 l3 22.3 22.5 22.7 0.878 0.886 0.894 l4 1.29 0.051 l5 2.6 3 0.102 0.118 l6 15.1 15.8 0.594 0.622 l7 6 6.6 0.236 0.260 l9 0.2 0.008 m 4.23 4.5 4.75 0.167 0.177 0.187 m1 3.75 4 4.25 0.148 0.157 0.167 v4 40? (typ.) l l1 a c l5 d1 l2 l3 e m1 m d h3 dia. l7 l6 f1 h2 f gg1 e1 f e l9 v4 r r r resin between leads h1 v3 h2 l8 vv v1 b vv v4 v4 outline and mechanical data L4925 6/8
jedec mo-166 powerso20 e a2 a e a1 pso20mec detail a t d 1 11 20 e1 e2 h x 45 detail a lead slug a3 s gage plane 0.35 l detail b r detail b (coplanarity) gc - c - seating plane e3 b c n n h bottom view e3 d1 dim. mm inch min. typ. max. min. typ. max. a 3.6 0.142 a1 0.1 0.3 0.004 0.012 a2 3.3 0.130 a3 0 0.1 0.000 0.004 b 0.4 0.53 0.016 0.021 c 0.23 0.32 0.009 0.013 d (1) 15.8 16 0.622 0.630 d1 9.4 9.8 0.370 0.386 e 13.9 14.5 0.547 0.570 e 1.27 0.050 e3 11.43 0.450 e1 (1) 10.9 11.1 0.429 0.437 e2 2.9 0.114 e3 5.8 6.2 0.228 0.244 g 0 0.1 0.000 0.004 h 15.5 15.9 0.610 0.626 h 1.1 0.043 l 0.8 1.1 0.031 0.043 n 10? (max.) s t10 0.394 (1) "d and f" do not include mold flash or protrusions. - mold flash or protrusions shall not exceed 0.15 mm (0.006"). - critical dimensions: "e", "g" and "a3" outline and mechanical data 8? (max.) 10 L4925 7/8
information furnished is believed to be accurate and reliable. however, stmicroelectronics assumes no responsibility for the co nsequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. no license is granted by implication or otherwise under any patent or patent rights of stmicroelectronics. specification mentioned in this pu blication are subject to change without notice. this publication supersedes and replaces all information previously supplied. stmicroelectron ics products are not authorized for use as critical components in life support devices or systems without express written approval of stmicr oelectronics. the st logo is a registered trademark of stmicroelectronics ? 2000 stmicroelectronics C printed in italy C all rights reserved stmicroelectronics group of companies australia - brazil - china - finland - france - germany - hong kong - india - italy - japan - malaysia - malta - morocco - singapore - spain - sweden - switzerland - united kingdom - u.s.a. http://www.st.com L4925 8/8
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