this is advanced information on a new product now in development or undergoing evaluation. details are subject to change without notice. L4937NPD november 1995 dual 5v multifunction voltage regulator prel im inary data . standbyoutput voltageprecision 5v 2% . output 2 tracked to the standby out- put . output 2 disable function for standby mode . very low quiescent current, less than 260 m a, in standby mode . output currents : i 01 = 50ma, i 02 = 500ma . very low dropout (max 0.4v/0.6v) . operating transient supply voltage up to 40v . power-on reset circuit sensing the standby output voltage . power-on reset delay pulse defined by the external capacitor . thermal shutdown and shortcircuit protections powerso20 ordering number: L4937NPD description the L4937NPD is a monolithic integrated dual volt- age regulators with two very low dropout outputs andadditionalfunctionssuchas power-onresetand input voltage sense. they are designed for supply- ing microcomputer controlled systems specially in automotive applications. pin connection (top view) gnd n.c. n.c. v s v s n.c. gnd ct en n.c. gnd 10 8 9 7 6 5 4 3 2 13 14 15 16 17 19 18 20 12 1 11 gnd d95at162a n.c. reset v o1 gnd n.c. v o2 n.c. gnd 1/9
block diagram reg1 1.23v reference reg2 reset 2.0v 1.23v v s1 v s2 en res ct v o2 v o1 gnd d95at163 2 m thermal data symbol parameter value unit r thj-case thermal resistance junction-case max. 1.5 c/w L4937NPD 2/9
absolute maximum ratings symbol parameter value unit v s dc supply voltage 28 v transient supply voltage (t < 1s) 40 v t j ,t stg junction and storage temperature range 55 to 150 c i en enable input current (v en 0.3v) 1ma v en enable input voltage v s v res reset output voltage 20 v i res reset output current 5 ma p d power dissipation 875 mw reg1 1.23v reference reg2 reset 2.0v 1.23v v s1 v s2 en res ct v o2 v o1 gnd d95at164 c s ct c o1 2 m application circuit c s 1 m f;c 01 6 m f;c 02 10 m f, esr < 10 w at 10khz note : the circuit is esd protected according to milstd883c. L4937NPD 3/9
electrical characteristics (v s = 14v; 40 c t j 125 c unless otherwise specified) symbol parameter test conditions min. typ. max. unit v s operating supply voltage 25 v v o1 standby output voltage 6v v s 25v 1ma i o1 50ma 4.90 5.00 5.10 v v o2 -v o1 output voltage 2 tracking error 6v v s 25v 5ma i o2 500ma enable = low 25 +25 mv v dp1 dropout voltage 1 i o1 = 10ma i o1 = 50ma 0.1 0.2 0.25 0.4 v v v io1 input to output voltage difference in undervoltage condition vs = 4v, i o1 = 35ma 0.4 v v dp2 dropout voltage 2 io1 = 100ma i o1 = 500ma 0.2 0.3 0.3 0.6 v v v io2 input to output voltage difference in undervoltage condition vs = 4.6v, i o1 = 350ma 0.6 v v ol 1.2 line regulation 6v v s 25v i o1 = 1ma; i o2 = 5ma 20 mv v olo1 load regulation 1 1ma i o1 50ma 25 mv v olo2 load regulation 2 5ma i o2 500ma 50 mv i lim1 current limit 1 v o1 = 4.5v v o1 = 0v (note 1) 55 25 100 50 200 100 ma ma i lim2 current limit 2 v o2 = 0v 550 1000 1700 ma i qsb quiescent current standby mode (output 2 disabled) i o1 = 0.3ma; t j < 100 c v en 2.4v v s = 14v v s = 3.5v 210 340 290 850 m a m a i q quiescent current i o1 = 50ma i o1 = 500ma 30 ma enable v enl enable input low voltage (output 2 active) 0.3 1.5 v v enh enable input high voltage 2.4 7 v v enhyst enable hysteresis 30 75 200 mv i en enable input current 0v < v en < 1.2v 2.5v < v en <7v 10 1 1.5 0 0.5 +1 m a m a L4937NPD 4/9
functional description the l4937ndis based on the sgs-thomson mi- croelectronics modular voltage regulator approach. several out-standing features and auxiliary func- tions are provided to meet the requirements of sup- plying the microprocessor systems used in automo- tive applications. furthermore the device is suitable also in other ap- plications requiring two stabilized voltages. the modular approach allows other features and functions to be realized easily when required. standby regulator the standby regulator uses an isolated collector vertical pnp transistor as the regulating element. this structure allows a very low dropout voltage at currents up to 50ma. the dropout operation of the standby regulator is maintained down to 2v input supply voltage. the output voltage is regulated up to the transientinput supplyvoltageof 40v.this fea- ture avoids functional interruptions which could be generated by overvoltage pulses. the typical curve of the standby output voltage as a functionof the input supply voltage is shown in fig. 1. the current consumption of the device (quiescent current) is less than 260 m a when output 2 is dis- abled (standby mode). the dropout voltage is con- trolled to reduce the quiescent current peak in the undervoltage region and to improve the transient response in this region. the quiescentcurrent isshown in fig. 2 as a function of the supply input voltage 2. output 2 voltage the output 2 regulator uses the same output struc- ture as the standbyregulator, but rated for an output current of 500ma. the output 2 regulatorworks in tracking mode with the standby output voltage as a reference voltage when the output 2. the output 2 regulator can be switched off via the enable input. note : 1: foldback characteristic electrical characteristics (continued) reset symbol parameter test conditions min. typ. max. unit v rt reset low threshold voltage v o1 -0.4 4.7 v o1 -0.1 v v rth reset threshold hysteresis 50 100 200 mv t rd reset pulse delay c t = 100nf; t r > 100 m s 55 100 180 ms t rr reset reaction time c t = 100nf 1 10 50 m s v rl reset output low voltage r res = 10k w to v 01 v s = 1.5v 0.4 v i lres reset output high leakage v res =5v 1 m a v cth delay comparator threshold 2.0 v v cth, hyst delay comparator threshold hysteresis 100 mv figure 1 : output voltage vs. input voltage. L4937NPD 5/9
figure 2 : quiescentcurrent vs. supply voltage. figure 3 : programmable output 2 voltage with external resistors. 400 m 200 m reset circuit theblockcircuit diagramof thereset circuit is shown in fig.4. the resetcircuit supervisesthe standbyout- put voltage. the reset threshold of 4.7v is defined by the internal reference voltage and the standby output divider. the reset pulse delay time t rd , is defined by the charge time of an external capacitor c t : c t x2v t rd = 2 m a the reactiontime of the reset circuit dependson the discharge time limitation of the reset capacitor c t and is proportional to the value of c t . the reaction time of the reset circuit increases the noise immunity. in fact,if the standbyoutputvoltage drops below the reset threshold for a time shorter than the reaction time t rr , no reset output variation occurs. the nominal reset delay is generated for standby output voltage drops longer than the time necessary for the complete discharging of the ca- pacitor c t . this time is typically equal to 50 m sif c t = 100nf.the typical reset output waveforms are shown in fig. 5. L4937NPD 6/9
figure 4 : block diagram of the reset circuit. vinput vout1 vout1 vrt +0.2v vrt 1.5v reset t r t rd t rd t rr d95at216 figure 5 : typical reset output waveforms. L4937NPD 7/9
e a2 a e a1 pso20mec detail a t d 110 11 20 e1 e2 hx45 detail a lead slug a3 s gage plan e 0.35 l detail b r detail b (coplanarity) gc -c- seating plane e3 b c n n powerso20 package mechanical data dim. mm inch min. typ. max. min. typ. max. a 3.60 0.1417 a1 0.10 0.30 0.0039 0.0118 a2 3.30 0.1299 a3 0 0.10 0 0.0039 b 0.40 0.53 0.0157 0.0209 c 0.23 0.32 0.009 0.0126 d (1) 15.80 16.00 0.6220 0.6299 e 13.90 14.50 0.5472 0.570 e 1.27 0.050 e3 11.43 0.450 e1 (1) 10.90 11.10 0.4291 0.437 e2 2.90 0.1141 g 0 0.10 0 0.0039 h 1.10 l 0.80 1.10 0.0314 0.0433 n10 (max.) s8 (max.) t 10.0 0.3937 (1) od and e1o do not include mold flash or protrusions - mold flash or protrusions shall not exceed 0.15mm (0.006o) L4937NPD 8/9
information furnished is believed to be accurate and reliable. however, sgs-thomson microelectronics assumes no responsibility for the consequences 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 sgs-thomson microelectronics. specifica- tions mentioned in this publication are subject to change without notice. this publication supersedes and replaces all information pre- viously supplied. sgs-thomson microelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of sgs-thomson microelectronics. ? 1995 sgs-thomson microelectronics - all rights reserved sgs-thomson microelectronics group of companies australia - brazil - france - germany - hong kong - italy - japan - korea - malaysia - malta - morocco - the netherlands - singapore - spain - sweden - switzerland - taiwan - thaliand - united kingdom - u.s.a. L4937NPD 9/9
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