Datasheet

ManualsBrandsST ManualsDC / DC Adjustable Switching RegulatorsSwitching Voltage RegulatorSwitching Regulator/Step-down Regulator Heptawatt 2.5A

L4960

2.5A POWER SWITCHING REGULATOR

2.5A OUTPUT CURRENT

5.1V TO 40V OPUTPUT VOLTAGE RANGE

PRECISE (

2%) ON-CHIP REFERENCE

HIGH SWITCHING FREQUENCY

VERY HIGH EFFICIENCY (UP TO 90%)

VERY FEW EXTERNAL COMPONENTS

SOFT START

INTERNAL LIMITING CURRENT

THERMAL SHUTDOWN

DESCRIPTION

The L4960 is a monolithic power switching regula-

tor delivering 2.5A at a voltage variable from 5V to

40V in step down configuration.

Features of the device include current limiting, soft

start, thermal protection and 0 to 100% duty cycle

for continuous operation mode.

June 2000

ORDERING NUMBERS

: L4960 (Vertical)

L4960H (Horizontal)

HEPTAWATT

BLOCK DIAGRAM

The L4960 is mounted in a Heptawatt plastic power

package and requires very few external compo-

nents.

Efficient operation at switching frequencies up to

150KHz allows a reduction in the size and cost of

external filter components.

1/16

Summary of content (17 pages)

PAGE 1
L4960 ® 2.5A POWER SWITCHING REGULATOR 2.5A OUTPUT CURRENT 5.1V TO 40V OPUTPUT VOLTAGE RANGE PRECISE (± 2%) ON-CHIP REFERENCE HIGH SWITCHING FREQUENCY VERY HIGH EFFICIENCY (UP TO 90%) VERY FEW EXTERNAL COMPONENTS SOFT START INTERNAL LIMITING CURRENT THERMAL SHUTDOWN DESCRIPTION The L4960 is a monolithic power switching regulator delivering 2.5A at a voltage variable from 5V to 40V in step down configuration.
PAGE 2
L4960 PIN CONNECTION (Top view) ABSOLUTE MAXIMUM RATINGS Symbol V1 V1 - V7 V7 V3, V6 V2 I3 I5 Ptot Tj, Tstg Parameter Input voltage Input to output voltage difference Negative output DC voltage Negative output peak voltage at t = 0.1µs; f = 100KHz Voltage at pin 3 and 6 Voltage at pin 2 Pin 3 sink current Pin 5 source current Power dissipation at Tcase ≤ 90°C Junction and storage temperature Value 50 50 -1 -5 5.
PAGE 3
L4960 THERMAL DATA Symbol Parameter Value Unit Rth j-case Thermal resistance junction-case max 4 °C/W Rth j-amb Thermal resistance junction-ambient max 50 °C/W ELECTRICAL CHARACTERISTICS (Refer to the test circuit, Tj = 25 °C, Vi = 35V, unless otherwise specified) Symbol Parameter Test Conditions Min. Typ. Max. Unit Vref 40 V 9 46 V DYNAMIC CHARACTERISTICS Vo Output voltage range Vi = 46V Io = 1A Vi Input voltage range Vo = Vref to 36V Io = 2.
PAGE 4
L4960 ELECTRICAL CHARACTERISTICS (continued) Symbol Parameter Test Conditions Min. Typ. Max. Unit 30 40 mA 15 20 mA 1 mA DC CHARACTERISTICS I1Q Quiescent drain current 100% duty cycle pins 5 and 7 open Vi = 46V 0% duty cycle -I7L Output leakage current 0% duty cycle SOFT START I6SO Source current 100 140 180 µA I6SI Sink current 50 70 120 µA ERROR AMPLIFIER V3H High level output voltage V2 = 4.7V I3 = 100µA V3L Low level output voltage V2 = 5.
PAGE 5
L4960 CIRCUIT OPERATION (refer to the block diagram) The L4960 is a monolithic stepdown switching regulator providing output voltages from 5.1V to 40V and delivering 2.5A. The regulation loop consists of a sawtooth oscillator, error amplifier, comparator and the output stage. An error signal is produced by comparing the output voltage with a precise 5.1V on-chip reference (zener zap trimmed to ± 2%).
PAGE 6
L4960 Figure 3. Test and application circuit C6, C7: EKR (ROE) L1 = 150µH at 5A (COGEMA 946042) CORE TYPE: MAGNETICS 58206-A2 MPP N° TURNS 45, WIRE GAUGE: 0.8mm (20 AWG) Figure 4. Quiescent drain current vs. supply voltage (0% duty cycle) 6/16 Figure 5. Quiescent drain current vs. supply voltage (100% duty cycle) Figure 6. Quiescent drain current vs.
PAGE 7
L4960 Figure 7. Quiescent drain current vs. junction temperature (100% duty cycle) Figure 8. Reference voltage (pin 2) vs. Vi Figure 9. Reference voltage versus junction temperature (pin 2) Figure 10. Open loop frequency and phase responde of error amplifier Figure 11. Switching frequency vs. input voltage Figure 12. Switching frequency vs. junction temperature Figure 13. Switching frequency vs. R2 (see test circuit) Figure 14. Line transient response Figure 15.
PAGE 8
L4960 Figure 16. Supply voltage ripple rejection vs. frequency Figure 17. Dropout voltage between pin 1 and pin 7 vs. current at pin 7 Figure 18. Dropout voltage between pin 1 and 7 vs. junction temperature Figure 19. Power dissipation derating curve Fi gure 20. Effici ency vs. output current Fi gure 21 . Effi ciency vs. output current F igu re 22. Effi ciency vs. output current 8/16 Fi gure 2 3. Effi ciency vs.
PAGE 9
L4960 APPLICATION INFORMATION Figure 24. Typical application circuit C1, C6, C7: EKR (ROE) D1: BYW80 OR 5A SCHOTTKY DIODE SUGGESTED INDUCTOR: L1 = 150µH at 5A CORE TYPE: MAGNETICS 58206 - A2 - MPP N° TURNS: 45, WIRE GAUGE: 0.8mm (20 AWG), COGEMA 946042 U15/GUP15: N° TURNS: 60, WIRE GAUGE: 0.8mm (20 AWG), AIR GAP: 1mm, COGEMA 969051. Figure 25. P.C. board and component layout of the Fig. 24 (1 : 1 scale) Resistor values for standard output voltages Vo 12V 15V 18V 24V R3 4.7KΩ 4.7KΩ 4.7KΩ 4.7KΩ R4 6.
PAGE 10
L4960 APPLICATION INFORMATION Figure 26. A minimal 5.1V fixed regulator; Very few component are required * COGEMA 946042 (TOROID CORE) 969051 (U15 CORE) ** EKR (ROE) Figure 27. Programmable power supply Vo = 5.1V to 15V Io = 2.5A max Load regulation (1A to 2A) = 10mV (Vo = 5.
PAGE 11
L4960 APPLICATION INFORMATION (continued) Figure 28. Microcomputer supply with + 5.
PAGE 12
L4960 APPLICATION INFORMATION (continued) Figure 29. DC-DC converter 5.1V/4A, ± 12V/2.5A; a suggestion how to synchronize a negative output L1, L3 = COGEMA 946042 (969051) L2 = COGEMA 946044 (946045) D1, D2, D3 = BYW80 Figure 30.
PAGE 13
L4960 APPLICATION INFORMATION (continued) Figure 31. Regulator for distributed supplies MOUNTING INSTRUCTION The power dissipated in the circuit must be removed by adding an external heatsink. Thanks to the Heptawatt package attaching the hetsink is very simple, a screw or a compression spring (clip) being sufficient. Between the heatsink and the package it is better to insert a layer of silicon grease, to optimize the thermal contact, no electrical isolation is needed between the two surfaces.
PAGE 14
L4960 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.
PAGE 15
L4960 mm DIM. MIN. TYP. inch 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 F 0.6 0.8 0.024 0.031 F1 0.9 0.035 G 2.41 2.54 2.67 0.095 0.100 0.105 G1 4.91 5.08 5.21 0.193 0.200 0.205 G2 7.49 7.62 7.8 0.295 0.300 0.307 H2 H3 10.4 10.05 L 10.4 0.409 0.396 0.409 14.2 0.559 L1 4.4 0.173 L2 15.8 0.622 L3 5.1 0.201 L5 2.6 3 0.102 0.118 L6 15.1 15.8 0.594 0.
PAGE 16
L4960 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.
PAGE 17
This datasheet has been download from: www.datasheetcatalog.com Datasheets for electronics components.