L4937N DUAL MULTIFUNCTION VOLTAGE REGULATOR . . . . .. . . . . STANDBYOUTPUT VOLTAGEPRECISION 5V ± 2% OUTPUT 2 TRACKED TO THE STANDBY OUTPUT OUTPUT 2 DISABLE FUNCTION FOR STANDBY MODE VERY LOW QUIESCENT CURRENT, LESS THAN 250µA, IN STANDBY MODE OUTPUT CURRENTS : I01 = 50mA, I02 = 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 THERMALSHUTDOWN AND SHORTCIRCUIT PROTECTIONS Heptawatt ORDERING NUMBER : L4937N DESCRIPTION The L4937N is a monolithic integrated dual voltage regulatorswith two very low dropout outputsand additional functions such as power-on reset and input voltage sense. It is designed for supplying microcomputer controlled systems specially in automotive applications. PIN CONNECTION (top view) June 2000 1/9 L4937N BLOCK DIAGRAM THERMAL DATA Symbol Rthj-case 2/9 Parameter Thermal Resistance Junction-Case Max. Value Unit 3 °C/W L4937N ABSOLUTE MAXIMUM RATINGS Symbol VS Parameter DC Supply Voltage Transient Supply Voltage (T < 1s) Tj, Tstg Junction and Storage Temperature Range Value Unit 28 V 40 V –55 to 150 °C mA IEN Enable Input Current (V EN ≤0.3V) ±1 VEN Enable Input Voltage VS VRES Reset Output Voltage 20 V IRES Reset Output Current 5 mA PD Power Dissipation (TA = 80°C, R th heatsink = 9°C/W) 5 W Note : The circuit is ESD protected according to MIL–STD–883C. APPLICATION CIRCUIT CS ≥ 1µF ; C01 ≥ 6µF ; C02 ≥ 10µF, ESR < 10Ω at 10KHz 3/9 L4937N ELECTRICAL CHARACTERISTICS (VS = 14V; –40°C ≤ Tj ≤ 125°C unless otherwise specified) Symbol Parameter Test Conditions Min. VS Operating Supply Voltage VO1 Standby Output Voltage 6V ≤ VS ≤ 25V 1mA ≤ IO1 ≤ 50mA 4.90 Output Voltage 2 Tracking Error (note 1) 6V ≤ VS ≤ 25V 5mA ≤ IO2 ≤ 500mA Enable = LOW –25 VDP1 Dropout Voltage 1 IO1 = 10mA IO1 = 50mA VIO1 Input to Output Voltage Difference in Undervoltage Condition VS = 4V, IO1 = 35mA VDP2 Dropout Voltage 2 IO2 = 100mA IO2 = 500mA VIO2 Input to Output Voltage Difference in Undervoltage Condition VOL 1.2 Typ. Max. Unit 25 V 5.10 V +25 mV 0.25 0.4 V V 0.4 V 0.3 0.6 V V VS = 4.6V, IO2 = 350mA 0.6 V Line Regulation 6V ≤ VS ≤ 25V IO1 = 1mA; IO2 = 5mA 20 mV VOLO1 Load Regulation 1 1mA ≤ IO1 ≤ 50mA 25 mV VOLO2 Load Regulation 2 5mA ≤ IO2 ≤ 500mA 50 mV ILIM1 Current Limit 1 VO1 = 4.5V VO1 = 0V (note 2) 55 25 100 50 200 100 mA mA ILIM2 Current Limit 2 VO2 = 0V 550 1000 1700 mA IQSB Quiescent Current Standby Mode (output 2 disabled) IO1 = 0.3mA; TJ < 100°C VEN ≥ 2.4V VS = 14V VS = 3.5V 210 340 290 850 µA µA 30 mA VO2 - VO1 IQ Quiescent Current 5.00 0.1 0.2 0.2 0.3 IO1 = 50mA IO1 = 500mA ENABLE VENL Enable Input LOW Voltage (output 2 active) –0.3 1.5 V VENH Enable Input HIGH Voltage 2.4 7 V VENhyst IEN 4/9 Enable Hysteresis Enable Input Current 0V < VEN < 1.2V 2.5V < VEN < 7V 30 75 200 mV –10 –1 –1.5 0 –0.5 +1 µA µA L4937N ELECTRICAL CHARACTERISTICS (continued) RESET Symbol Parameter VRt Reset Low Threshold Voltage VRth Reset Threshold Hysteresis Test Conditions VS = 14V Min. Typ. Max. Unit Vo1 -0.4 4.7 Vo1 -0.1 V 50 100 200 mV tRD Reset Pulse Delay CT = 100nF; tR > 100µs 55 100 180 ms tRR Reset Reaction Time CT = 100nF 1 10 50 µs 0.4 V 1 µA VRL Reset Output LOW Voltage RRES = 10KΩ to V01 VS ≥ 1.5V ILRES Reset Output HIGH Leakage VRES = 5V VCTth Delay Comparator Threshold 2.0 V VCTth, hyst Delay Comparator Threshold Hysteresis 100 mV Note : 1 : VO2 connected to ADJ.VO2 can be set to higher values by inserting an external resistor divider. 2 : Foldback characteristic FUNCTIONAL DESCRIPTION The L4937N is based on the SGS-THOMSON Microelectronics modular voltage regulatorapproach. Several out-standing features and auxiliary functions are provided to meet the requirements of supplying the microprocessor systems used in automotive applications. Furthermore the device is suitable also in other applications requiring two stabilized voltages. The modular approach allows other features and functions to be realized easily when required. The typical curve of the standby output voltage as a functionof the input supply voltageis shownin fig. 1. The current consumption of the device (quiescent current) is less than 250µA when output 2 is disabled (standby mode). The dropout voltage is controlled to reduce the quiescent current peak in the undervoltage region and to improve the transient response in this region. Thequiescent current isshown in fig.2 as a function of the supply input voltage 2. 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 transient input supplyvoltageof40V. This feature avoids functional interruptions which could be generated by overvoltage pulses. OUTPUT 2 VOLTAGE The output 2 regulator uses the same output structureas the standbyregulator, but ratedfor an output current of 500mA. The output 2 regulatorworks in tracking mode with the standby output voltage as a reference voltage. The output 2 regulator can be switched off via the Enable input. 5/9 L4937N Figure 1 : Output Voltage vs. Input Voltage. Figure 2 : Quiescent Current vs. Supply Voltage. 400 200 RESET CIRCUIT Theblock circuit diagramof the resetcircuit is shown in fig.3. Thereset circuit supervisesthe standbyoutput voltage. The reset threshold of 4.7V is defined by the internal reference voltage and the standby output divider. The reset pulse delay time tRD, is defined by the charge time of an external capacitor CT : CT x 2V tRD = 6/9 2µA The reaction time of the reset circuit dependson the discharge time limitation of the reset capacitor CT and is proportional to the value of CT. The reaction time of the reset circuit increases the noise immunity. In fact, if the standbyoutput voltage 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 capacitor CT. This time is typically equal to 50µs if CT = 100nF. The typical reset output waveforms are shown in fig. L4937N Figure 3 : Block Diagram of the Reset Circuit. Figure 4 : Typical Reset Output Waveforms. VOUT1 VINPUT VOUT1 VRT +0.2V VRT 1.5V tR RESET tRD tRD tRR D95AT216 7/9 L4937N DIM. A C D D1 E E1 F F1 G G1 G2 H2 H3 L L1 L2 L3 L4 L5 L6 L7 L9 M M1 V4 Dia MIN. mm TYP. 2.4 1.2 0.35 0.7 0.6 2.34 4.88 7.42 10.05 16.7 21.24 22.27 2.6 15.1 6 2.55 4.83 2.54 5.08 7.62 16.9 14.92 21.54 22.52 2.8 15.5 6.35 0.2 2.8 5.08 3.65 MAX. 4.8 1.37 2.8 1.35 0.55 0.97 0.8 0.9 2.74 5.28 7.82 10.4 10.4 17.1 21.84 22.77 1.29 3 15.8 6.6 inch TYP. MIN. 0.094 0.047 0.014 0.028 0.024 0.095 0.193 0.295 0.396 0.657 0.386 0.877 0.102 0.594 0.236 3.05 0.100 5.33 0.190 40° (typ.) 3.85 0.144 0.100 0.200 0.300 0.668 0.587 0.848 0.891 0.110 0.610 0.250 0.008 0.110 0.200 OUTLINE AND MECHANICAL DATA MAX. 0.189 0.054 0.110 0.053 0.022 0.038 0.031 0.035 0.105 0.205 0.307 0.409 0.409 0.673 0.860 0.896 0.051 0.118 0.622 0.260 0.120 0.210 Heptawatt V 0.152 V L V E L1 M1 A M D C D1 L5 H2 L2 L3 F E E1 V4 L9 H3 G H1 G1 G2 Dia. F L7 L4 L6 8/9 H2 F1 HEPTAMEC L4937N Information furnished is believed to be accurate and reliable. However, STMicroelectronics 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 STMicroelectronics. Specification mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics 2000 STMicroelectronics – Printed in Italy – All Rights Reserved HEPTAWATT is a Trademark of STMicroelectronics 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 9/9