Datasheet LT1933 (Analog Devices)

LT1933 600mA, 500kHz Step-Down Switching Regulator in SOT-23 and DFN Packages
FEATURES DESCRIPTION
n
Wide Input Range: 3.6V to 36V
The LT®1933 is a current mode PWM step-down DC/DC n 5V at 600mA from 16V to 36V Input converter with an internal 0.75A power switch, packaged n 3.3V at 600mA from 12V to 36V Input in a tiny 6-lead SOT-23. The wide input range of 3.6V n 5V at 500mA from 6.3V to 36V Input to 36V makes the LT1933 suitable for regulating power n 3.3V at 500mA from 4.5V to 36V Input from a wide variety of sources, including unregulated wall n Fixed Frequency 500kHz Operation transformers, 24V industrial supplies and automotive n Uses Tiny Capacitors and Inductors batteries. Its high operating frequency allows the use of n Soft-Start tiny, low cost inductors and ceramic capacitors, resulting n Internally Compensated in low, predictable output ripple. n Low Shutdown Current: <2μA Cycle-by-cycle current limit provides protection against n Output Adjustable Down to 1.25V shorted outputs, and soft-start eliminates input current n Low Profi le (1mm) SOT-23 (ThinSOT™) and surge during start up. The low current (<2μA) shutdown (2mm × 3mm × 0.75mm) 6-Pin DFN Packages provides output disconnect, enabling easy power manage- ment in battery-powered systems.
APPLICATIONS
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other n trademarks are the property of their respective owners. Automotive Battery Regulation n Industrial Control Supplies n Wall Transformer Regulation n Distributed Supply Regulation n Battery-Powered Equipment
TYPICAL APPLICATION Effi ciency
95
3.3V Step-Down Converter
VIN = 12V 1N4148 90 V VOUT = 5V IN V 4.5V TO 36V IN BOOST 85 LT1933 0.1μF 22μH V VOUT = 3.3V OFF ON OUT SHDN SW 3.3V/500mA 80 GND FB MBRM140 16.5k EFFICIENCY (%) 75 2.2μF 10k 22μF 70 65 1933 TA01a 0 100 200 300 400 500 600 LOAD CURRENT (mA) 1933 TA01b 1933fe 1