LT1936 1.4A, 500kHz Step-Down Switching Regulator FEATURES DESCRIPTION Wide Input Range: 3.6V to 36V The LT 1936 is a current mode PWM step-down DC/DC Short-Circuit Protected Over Full Input Range converter with an internal 1.9A power switch, packaged 1.9A Guaranteed Minimum Switch Current in a tiny, thermally enhanced 8-lead MSOP. The wide in- 5V at 1.4A from 10V to 36V Input put range of 3.6V to 36V makes the LT1936 suitable for 3.3V at 1.4A from 7V to 36V Input regulating power from a wide variety of sources, including 5V at 1.2A from 6.3V to 36V Input automotive batteries, 24V industrial supplies and unregu- 3.3V at 1.2A from 4.5V to 36V Input lated wall adapters. Its high operating frequency allows the Output Adjustable Down to 1.20V use of small, low cost inductors and ceramic capacitors, 500kHz Fixed Frequency Operation resulting in low, predictable output ripple. Soft-Start Cycle-by-cycle current limit, frequency foldback and Uses Small Ceramic Capacitors thermal shutdown provide protection against shorted Internal or External Compensation outputs, and soft-start eliminates input current surge Low Shutdown Current: <2A during start-up. Transient response can be optimized by Thermally Enhanced 8-Lead MSOP Package using external compensation components, or board space can be minimized by using internal compensation. The low current (<2A) shutdown mode enables easy power APPLICATIONS management in battery-powered systems. Automotive Battery Regulation L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other Industrial Control Supplies trademarks are the property of their respective owners. Unregulated Wall Adapters TYPICAL APPLICATION 3.3V Step-Down Converter Ef ciency 95 V = 12V IN V IN 4.5V TO 36V V = 5V OUT 90 0.22F V BOOST IN 10H V OUT ON OFF SHDN SW 3.3V 85 1.2A V = 3.3V OUT LT1936 4.7F 17.4k 80 COMP FB V GND 75 C 10k 22F 70 1936 TA01a 65 0 0.5 1 1.5 LOAD CURRENT (A) 1936 TA01b 1936fd 1 EFFICIENCY (%)LT1936 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) V Voltage ................................................. 0.4V to 36V IN TOP VIEW BOOST Voltage .........................................................43V BOOST 1 8 COMP BOOST Above SW Voltage ........................................20V V 2 7 V IN C 9 6 FB SW 3 SHDN Voltage ............................................ 0.4V to 36V GND 4 5 SHDN FB, V , COMP Voltage .................................................6V C MS8E PACKAGE 8-LEAD PLASTIC MSOP Operating Temperature Range (Note 2) = 40C/W, = 10C/W JA JC LT1936E ............................................... 40C to 85C EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB LT1936I .............................................. 40C to 125C LT1936H ............................................ 40C to 150C Maximum Junction Temperature LT1936E, LT1936I ............................................. 125C LT1936H ........................................................... 150C Storage Temperature Range ................... 65C to 150C Lead Temperature (Soldering, 10 sec) .................. 300C ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LT1936EMS8E PBF LT1936EMS8E TRPBF LTBMT 8-Lead Plastic MSOP 40C to 85C LT1936IMS8E PBF LT1936IMS8E TRPBF LTBRV 8-Lead Plastic MSOP 40C to 125C LT1936HMS8E PBF LT1936HMS8E TRPBF LTBWB 8-Lead Plastic MSOP 40C to 150C LEAD BASED FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE LT1936EMS8E LT1936EMS8E TR LTBMT 8-Lead Plastic MSOP 40C to 85C LT1936IMS8E LT1936IMS8E TR LTBRV 8-Lead Plastic MSOP 40C to 125C LT1936HMS8E LT1936HMS8E TR LTBWB 8-Lead Plastic MSOP 40C to 150C Consult LTC Marketing for parts speci ed with wider operating temperature ranges. For more information on lead free part marking, go to: