L5973D 2.5 A switch step down switching regulator Features 2.5 A internal switch Operating input voltage from 4 V to 36 V 3.3 V / (2%) reference voltage HSOP8 exposed pad Output voltage adjustable from 1.235 V to 35 V Low dropout operation: 100 % duty cycle Description 250 kHz internally fixed frequency Voltage feedforward The L5973D is a step down monolithic power switching regulator with a minimum switch current Zero load current operation limit of 2.5 A so it is able to deliver more than 2 A Internal current limiting DC current to the load depending on the Inhibit for zero current consumption application conditions. The output voltage can be set from 1.235 V to Synchronization 35 V. The high current level is also achieved Protection against feedback disconnection thanks to an SO8 package with exposed frame, Thermal shutdown that allows to reduce the Rth(j-amb) down to approximately 40 C/W. The device uses an internal P-channel D-MOS Applications transistor (with a typical Rdson of 250 m) as Consumer: STB, DVD, TV, VCR, car radio, switching element to minimize the size of the LCD monitors external components. An internal oscillator fixes the switching frequency Networking: XDSL, modems, DC-DC modules at 250 kHz. Computer: printers, audio/graphic cards, Having a minimum input voltage of 4 V only, it is optical storage, hard disk drive particularly suitable for 5 V bus, available in all Industrial: changers, car battery, DC-DC computer related applications. converters Pulse by pulse current limit with the internal frequency modulation offers an effective constant current short circuit protection. Figure 1. Test application circuit VREF L1 15H 3.3V VOUT=3.3V 6 OUT 1 VIN = 4.4V to 35V VCC D1 8 R1 L5973D STPS340U SYNC. 2 5.6K C2 5 COMP 330F 3 7 C1 4 FB 10V C4 10F INH GND 22nF 35V R2 CERAMIC 3.3K C3 R3 220pF 4.7K D03IN1439 January 2008 Rev 16 1/17 www.st.com 17Contents L5973D 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 13 8 Order code 15 9 Revision history . 16 2/17