L5970D STMicroelectronics

L5970D Up to 1A step down switching regulator Features Up to 1A output current Operating input voltage from 4.4V to 36V 3.3V / (2%) reference voltage SO8 Output voltage adjustable from 1.2V to 35V Low dropout operation: 100% duty cycle Description 250KHz Internally fixed frequency Voltage feedforward The L5970D is a step down monolithic power switching regulator capable to deliver up to 1A at Zero load current operation output voltages from 1.2V to 35V. Internal current limiting The device uses an internal P-Channel D-MOS Inhibit for zero current consumption transistor (with a typical Rdson of 250m) as Synchronization switching element to minimize the size of the Protection against feedback disconnection external components. Thermal shutdown An internal oscillator fixes the switching frequency at 250KHz. Applications Having a minimum input voltage of 4.4V only, it is particularly suitable for 5V bus, available in all Consumer: STB, DVD, TV, VCR, car radio, computer related applications. LCD monitors Pulse by pulse current limit with the internal Networking: XDSL, modems, DC-DC modules frequency modulation offers an effective constant Computer: printers, audio/graphic cards, current short circuit protection. optical storage, hard disk drive Industrial: changers, car battery, DC-DC converters Figure 1. Test application circuit VREF L1 33H 3.3V VOUT=3.3V 6 OUT 1 VIN = 4.4V to 35V VCC D1 8 R1 L5970D STPS2L40U SYNC. 2 5.6K C2 FB 5 COMP 100F C1 3 7 4 10V C4 10F INH. GND 22nF 35V R2 CERAMIC C3 3.3K R3 220pF 4.7K D98IN954C October 2007 Rev 16 1/16 www.st.com 16Contents L5970D Contents 1 Pin settings 3 1.1 Pin connection 3 1.2 Pin description 3 2 Electrical data 4 2.1 Maximum ratings 4 2.2 Thermal data . 4 3 Electrical characteristics . 5 4 Typical characteristics . 7 5 Application circuit . 9 6 Application ideas . 11 7 Package mechanical data 12 8 Order code 14 9 Revision history . 15 2/16