L4972 STMicroelectronics, L4972 Datasheet
L4972
Available stocks
Related parts for L4972
L4972 Summary of contents
Page 1
... POW ERDIP ( ORDERING NUMBERS : L4972A (Powerdip) L4972AD (SO20) the L4972A include reset and power fail for micro- processors, feed forward line regulation, soft start, limiting current and thermal protection. The device is mountedin a Powerdip16 + and SO20large plastic packages and requires few external compo- nents ...
Page 2
... L4972A-L4972AD ABSOLUTE MAXIMUM RATINGS Symbo l V Input Voltage 11 V Input Operating Voltage 11 V Output DC Voltage 20 Output Peak Voltage 0 200khz I Maximum Output Current 20 V Boostrap Voltage I Boostrap Operating Voltage Input Voltage at Pins Reset Output Voltage 3 I Reset Output Sink Current ...
Page 3
... The Feedback Terminal of the Regulation Loop. The output is connected directly to this terminal for 5.1V operation connected via a divider for higher voltages. 10 SYNC INPUT Multiple L4972A’s are synchronized by connecting pin 10 inputs together or via an external syncr. pulse. 11 SUPPLY VOLTAGE Unregulated Input Voltage. ...
Page 4
... L4972A-L4972AD CIRCUIT OPERATION The L4972A monolithic stepdown switching regulatorworking in continuousmode realized inthe new BCD Technology. This technology allows the integration of isolated vertical DMOS power transis- tors plus mixed CMOS/Bipolar transistors. The device can deliver output voltage ad- justable from 5.1V to 40V and contains diagnostic and control functions that make it particularly suit- able for microprocessor based systems ...
Page 5
... Figure 1 : Feedforward Waveform. Figure 2 : Soft Start Function. Figure 3 : Limiting Current Function. L4972A-L4972AD 5/23 ...
Page 6
... L4972A-L4972AD Figure 4 : Reset and Power Fail Functions 6/23 ...
Page 7
... T yp 15V to 50V 1mA 125 C 0 est Cond ition Min. T yp. 11 50V 0 1mA L4972A-L4972AD = 30K , 4 Max. Unit Fig . 5 0 110 KHz ...
Page 8
... L4972A-L4972AD ELECTRICAL CHARACTERISTICS (continued) DC CHARACTERISTICS Symbo l Parameter V Turn-on Threshold 11on V Turn-off Hysteresys 11 Hyst I Quiescent Current 11Q I Operating Supply Current 11OQ I Out Leak Current 20L SOFT START (pin 8) Symbo l Parameter I Soft Start Source Current 8 V Output Saturation Voltage 8 ERROR AMPLIFIER Symbo l Parameter ...
Page 9
... 50V 4. 5.3V 4.7V 15mA 4. 50V 4.95 13 0.4 = 100KHz) sw L4972A-L4972AD Max. Unit Fig . ref ref -100 -80 mV Vref ref -200 -160 mV 5.1 5. 1.1 1 ...
Page 10
... ESR. 10/23 Table 12V 4.7k 15V 4.7k 18V 4.7k 24V 4.7k Note: In the Test and Application Circuit for L4972D are not mounted C2, C14 and R8. Table B SUGGESTED BOOSTRAP CAPACITORS Operatin g F requency Boo strap Cap.c10 f = 20KHz 680nF f = 50KHz 470nF f = 100KHz 330nF f = 200KHz 220nF f = 500KHz 100nF ...
Page 11
... Figure 6b: P.C. Board and Component Layout of the Circuit of Fig. 5. (1:1 scale) Figure Test Circuits. L4972A-L4972AD 11/23 ...
Page 12
... L4972A-L4972AD Figure 7A. Figure 7B. Figure 7C. 12/23 ...
Page 13
... Figure 7D. Figure 8 : Quiescent Drain Current vs. Supply Voltage (0% duty cycle - see fig. 7A). L4972A-L4972AD Figure 9 : QuiescentDrain Current vs. Junction Temperature (0% duty cycle). 13/23 ...
Page 14
... L4972A-L4972AD Figure 10 : Quiescent Drain Current vs. Duty Cy- cle. Figure 12 : Reference Voltage (pin 13) vs. Junc- tion Temperature (see fig. 7). Figure 14 : Reference Voltage (pin 14) vs. Junc- tion Temperature (see fig. 7). 14/23 Figure 11 : Reference Voltage (pin 13) vs. Vi (see fig. 7). Figure 13 : ReferenceVoltage (pin 14) vs. Vi (see fig. 7). ...
Page 15
... Figure 16 : Switching Frequency vs. Input Voltage (see fig. 5). Figure 18 : Switching Frequency vs. R4 (see fig.5). Figure 20 : Supply Voltage Ripple Rejection vs. Frequency (see fig. 5). L4972A-L4972AD Figure 17 : Switching Frequency vs. Junction Temperature (see fig. 5). Figure 19 : Maximum Duty Cycle vs. Frequency. Figure 21 : Efficiency vs. Output Voltage. 15/23 ...
Page 16
... L4972A-L4972AD Figure 22 : Line Transient Response (see fig. 5). Figure 24 : Dropout Voltage between Pin 11 and Pin 20 vs. Current at Pin 20. Figure 26 : Power Dissipation (device only) vs. Input Voltage. 16/23 Figure 23 : Load Transient Response (see fig. 5). Figure 25 : .Dropout Voltage between Pin 11 and Pin 20 vs. Junction Temperature. Figure 27 : Power Dissipation (device only) vs. ...
Page 17
... Figure 28 : Power Dissipation (device only) vs. Output Voltage. Figure 30 : Power Dissipation (device only) vs. Output Current. Figure 32 : Efficiency vs. Output Current. L4972A-L4972AD Figure 29 : Power Dissipation (device only) vs. OutputVoltage. Figure 31 : Power Dissipation (device only) vs. Output Current. Figure 33 : Test PCB Thermal Characteristic. 17/23 ...
Page 18
... L4972A-L4972AD Figure 34 : Junctionto AmbientThermal Resistance vs. Area onBoard Heatsink (DIP 16+2+2) Figure 36: Maximum Allowable Power Dissipa- tion vs. Ambient Temperature (Pow- erdip) Figure 38: Open Loop Frequency and Phase of Er- ror Amplifier (see fig. 7C). 18/23 Figure 35: Junction to Ambient Thermal Resistance vs. Area on Board Heatsink (SO20) Figure 37: Maximum Allowable Power Dissipa- tion vs ...
Page 19
... Figure – 5.1V Low Cost Application Circuit. Figure 5.1V/12VMultiple Supply. Note the Synchronization between the L4972A and L4970A. L4972A-L4972AD 19/23 ...
Page 20
... L4972A-L4972AD Figure 41 : L4972A’s Sync. Example. Figure 42: 1A/24V Multiple Supply. Note the synchronization between the L4972A and L4962 20/23 ...
Page 21
... DIM. MIN. TYP. MAX. MIN. TYP. a1 0.51 0.020 B 0.85 1.40 0.033 b 0.50 0.020 b1 0.38 0.50 0.015 D 24.80 E 8.80 0.346 e 2.54 0.100 e3 22.86 0.900 F 7.10 I 5.10 L 3.30 0.130 Z 1.27 OUTLINE AND MECHANICAL DATA MAX. 0.055 0.020 0.976 0.280 0.201 Powerdip 20 0.050 L4972A-L4972AD 21/23 ...
Page 22
... L4972A-L4972AD mm DIM. MIN. TYP. MAX. MIN. A 2.35 2.65 0.093 A1 0.1 0.3 0.004 B 0.33 0.51 0.013 C 0.23 0.32 0.009 D 12.6 13 0.496 E 7.4 7.6 0.291 e 1. 10.65 0.394 h 0.25 0.75 0.010 L 0.4 1.27 0.016 K 0 (min.)8 (max 22/23 inch OUTLINE AND MECHANICAL DATA TYP. MAX. 0.104 0.012 0.020 0.013 0.512 0.299 0.050 0.419 0.030 0.050 ...
Page 23
... The ST logo is a registered trademark of STMicroelectronics 2000 STMicroelectronics – Printed in Italy – 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 L4972A-L4972AD 23/23 ...