L4972A STMicroelectronics, L4972A Datasheet
L4972A
Specifications of L4972A
L4972A
Available stocks
Related parts for L4972A
L4972A Summary of contents
Page 1
... SWITCHING FREQUENCY UP TO 200KHz ■ THERMAL SHUTDOWN ■ CONTINUOUS MODE OPERATION ■ 2 Description The L4972A is a stepdown monolithic power switching regulator delivering voltage vari- able from 5.1 to 40V. Realized with BCD mixed technology, the device Figure 2. Block Diagram May 2005 2A SWITCHING REGULATOR Figure 1. Packages PowerDIP20 (16+2+2) Table 1 ...
Page 2
... 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. Multiple L4972A’s are synchronized by connecting pin 10 inputs together or via an external syncr. pulse. Unregulated Input Voltage. ...
Page 3
... Circuit Operation The L4972A monolithic stepdown switching regulator working in continuous mode realized in the new BCD Technology. This technology allows the integration of isolated vertical DMOS power transistors plus mixed CMOS/Bipolar transistors. The device can deliver output voltage adjustable from 5.1V to 40V and contains diagnostic and control functions that make it particularly suitable for microprocessor based systems ...
Page 4
... L4972A stage. An error signal is produced by comparing the output voltage with the precise 5.1V ± chip reference. This error signal is then compared with the sawtooth oscillator in order to generate frixed fre- quency pulse width modulated drive for the output stage. A PWM latch is included to eliminate multiple pulsing within a period even in noisy environments ...
Page 5
... Figure 6. Limiting Current Function. Figure 7. Reset and Power Fail Functions A B L4972A 5/22 ...
Page 6
... L4972A 4 Electrical Characteristcs Table 5. Electrical Characteristcs Refer to the test circuit 25° specified. Symbol Parameter DYNAMIC CHARACTERISTICS V Input Volt. Range (pin 11 Output Voltage o ∆V Line Regulation o ∆V Load Regulation o V Dropout Voltage between Pin d 11 and 20 I Max Limiting Current 20L η ...
Page 7
... 50V 5. 50V 5.3V 50V;V = 4.7V 5.3V 4.7V 15mA 4. 50V L4972A = 100KHz typ, unless otherwise SW Min. Typ. Max. Unit 2 mA µA 80 115 150 1.2 V µA 100 150 µA 100 150 µA 0 1.2 1.5 V 2.5 V 5.5 V µA 270 300 2 ...
Page 8
... L4972A Table 5. Electrical Characteristcs (continued) Refer to the test circuit 25° specified. Symbol Parameter V Rising Threshold Voltage 4R V Hysteresis 4H I Input Bias Current 4 Figure 8. TYPICAL PERFORMANCES (using evaluation board 83 35V ; REF V = 30mV (at 1A) o RIPPLE Line regulation = 12mV ( 50V) i Load regulation = 7mV (I = 0.5 to 2A) o for component values Refer to the fig ...
Page 9
... In the Test and Application Circuit for L4972D are not mounted C2, C14 and R8. Table 7. Suggested Boostrap Capacitors Operating Frequency f = 20KHz f = 50KHz f = 100KHz f = 200KHz f = 500KHz R 9 4.7kΩ 4.7kΩ 4.7kΩ 4.7kΩ Boostrap Cap.c10 ≥680nF ≥470nF ≥330nF ≥220nF ≥100nF L4972A R 7 6.2kΩ 9.1kΩ 12Ω 18Ω 9/22 ...
Page 10
... L4972A Figure 10. P.C. Board and Component Layout of the Circuit of Fig. 8. Figure 11. DC Test Circuits Figure 12. 10/22 ...
Page 11
... Figure 13. Figure 14. Figure 15. Figure 16. Quiescent Drain Current vs. Supply Voltage (0% duty cycle - see fig. 12). Figure 17. Quiescent Drain Current vs. Junction Temperature (0% duty cycle). L4972A 11/22 ...
Page 12
... L4972A Figure 18. Quiescent Drain Current vs. Duty Cycle. Figure 19. Reference Voltage (pin 13) vs. Vi (see fig. 11). Figure 20. Reference Voltage (pin 13) vs. Junction Temperature (see fig. 11). 12/22 Figure 21. Reference Voltage (pin 14) vs. Vi (see fig. 11). Figure 22. Reference Voltage (pin 14) vs. Junction Temperature (see fig. 11). ...
Page 13
... Figure 24. Switching Frequency vs. Input Voltage (see fig. 8). Figure 25. Switching Frequency vs. Junction Temperature (see fig. 8). Figure 26. Switching Frequency vs. R4 (see fig.8). Figure 27. Maximum Duty Cycle vs. Frequency. Figure 28. Supply Voltage Ripple Rejection vs. Frequency (see fig. 8). Figure 29. Efficiency vs. Output Voltage. L4972A 13/22 ...
Page 14
... L4972A Figure 30. Line Transient Response (see fig. 8). Figure 31. Line Transient Response (see fig. 8). Figure 32. Dropout Voltage between Pin 11 and Pin 20 vs. Current at Pin 20. 14/22 Figure 33. .Dropout Voltage between Pin 11 and Pin 20 vs. Junction Temperature. Figure 34. Power Dissipation (device only) vs. Input Voltage. ...
Page 15
... Figure 36. Power Dissipation (device only) vs. Output Voltage. Figure 37. Power Dissipation (device only) vs. Output Voltage Figure 38. Power Dissipation (device only) vs. Output Current Figure 39. Power Dissipation (device only) vs. Output Current Figure 40. Efficiency vs. Output Current. Figure 41. Test PCB Thermal Characteristic. L4972A 15/22 ...
Page 16
... L4972A Figure 42. Rth j-amb vs. Area on Board Heatsink (DIP 16+2+2) Figure 43. Rth j-amb vs. Area on Board Heatsink (SO20) Figure 44. Maximum Allowable Power Dissipation vs. T (Powerdip) amb 16/22 Figure 45. Maximum Allowable Power Dissipation vs. Ambient Temperature (SO20) Figure 46. Open Loop Frequency and Phase of Error Amplifier (see fig. 14). ...
Page 17
... Figure 47. 2A – 5.1V Low Cost Application Circuit. Figure 48. A 5.1V/12V Multiple Supply. Note the Synchronization between the L4972A and L4970A. Figure 49. L4972A’s Sync. Example. L4972A 17/22 ...
Page 18
... L4972A Figure 50. 1A/24V Multiple Supply. Note the synchronization between the L4972A and L4962 18/22 ...
Page 19
... TYP. MAX. a1 0.51 B 0.85 1.40 b 0.50 b1 0.38 0.50 D 24.80 E 8.80 e 2.54 e3 22.86 F 7.10 I 5.10 L 3.30 Z 1.27 inch MIN. TYP. MAX. 0.020 0.033 0.055 0.020 0.015 0.020 0.976 0.346 0.100 0.900 0.280 0.201 0.130 0.050 OUTLINE AND MECHANICAL DATA Powerdip 20 L4972A 19/22 ...
Page 20
... L4972A Figure 52. SO20 Mechanical Data & Package Dimensions mm DIM. MIN. TYP. MAX. A 2.35 2.65 A1 0.10 0.30 B 0.33 0.51 C 0.23 0.32 (1) 12.60 13. 7.40 7.60 e 1.27 H 10.0 10.65 h 0.25 0.75 L 0.40 1.27 k 0˚ (min.), 8˚ (max.) ddd 0.10 (1) “D” dimension does not include mold flash, protusions or gate burrs ...
Page 21
... Revision History Table 8. Revision History Date Revision June 2000 May 2005 2 First Issue 3 Modified look & feel layout. Changed the name the Part list to page 9/22. Description of Changes L4972A 21/22 ...
Page 22
... L4972A 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. Specifications mentioned in this publication are subject to change without notice ...