LT3645 - 36V 500mA Step-Down Regulator and 200mA LDO - Linear Technology - #1

Text version of the page

LT3645 1 3645f LOAD CURRENT (mA) 0 100 50 EFFICIENCY (%) 60 70 80 90 200 300 3645 TA01b 400 500 VOUT = 3.3V VIN = 12V VOUT = 5V TYPICAL APPLICATION FEATURES DESCRIPTION 36V 500mA Step-Down Regulator and 200mA LDO The LT®3645 is a dual output regulator combining a 500mA buck regulator and a 200mA low dropout linear regulator (LDO). The wide input voltage range of 3.6V to 36V makes the LT3645 suitable for regulating power from a wide variety of sources, including 24V industrial supplies and automotive batteries. Its high operating frequency allows the use of tiny, low cost inductors and capacitors, resulting in a very small solution. Cycle-by-cycle current limit and frequency foldback provide protection against shorted outputs. Soft-start and frequency foldback eliminate input current surge during start-up. The linear regulator operates from the VCC2 pin at voltages down to 1.2V. It supplies 200mA of output current with a typical dropout voltage of 310mV. Other features of the LT3645 include a <2ìA shutdown, short circuit protection, soft-start and thermal shutdown. The LT3645 is available in the thermally enhanced 16-lead (3mm × 3mm) QFN package, or a 12-lead MSE package. 3.3V/5V Step-Down Converter APPLICATIONS n Automotive CMOS Image Sensors n Industrial/Automotive Micro-Controller Supply L, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Wide Input Range: Operation from 3.6V to 36V Overvoltage Lockout Protects Circuit Through 55V Transients on Input n 500mA Output Current Switching Regulator n High Switching Frequency: 750kHz n 200mA Low Dropout Linear Regulator 1.2V to 16V Input; 0.8V to 8V Output 310mV Dropout Voltage VCC2 to OUT2 n Precision Programmable Undervoltage Lockout n Short-Circuit Robust n Internal Soft-Start n <2ìA Shutdown Current n Small Thermally Enhanced 16-Lead (3mm × 3mm) QFN and 12-Lead MSE Packages Buck Regulator Effi ciency 1ìF 3645 TA01a PGOOD 6.2V TO 36V GND SW DA FB FB2 EN2 VCC2 VIN EN/UVLO NPG OUT2 10ìF 5V 300mA 3.3V 200mA 15ìH 52.3k 31.6k 10k 10k BOOST LT3645 2.2ìF 0.1ìF ON OFF