LTC3703-5 60V Synchronous Switching Regulator Controller UFEATURESDESCRIPTIO ■ High Voltage Operation: Up to 60V The LTC®3703-5 is a synchronous step-down switching ■ Large 1 Ω Gate Drivers (with 5V Supply) regulator controller that can directly step-down voltages ■ No Current Sense Resistor Required from up to 60V input, making it ideal for telecom and au- ■ Step-Up or Step-Down DC/DC Converter tomotive applications. The LTC3703-5 drives external logic ■ Dual N-Channel MOSFET Synchronous Drive level N-channel MOSFETs using a constant frequency (up ■ Excellent Line and Load Transient Response to 600kHz), voltage mode architecture. ■ Programmable Constant Frequency: 100kHz to A precise internal reference provides 1% DC accuracy. A 600kHz high bandwidth error amplifier and patented* line feed ■ ±1% Reference Accuracy forward compensation provide very fast line and load ■ Synchronizable up to 600kHz transient response. Strong 1Ω gate drivers allow the ■ Selectable Pulse Skip Mode Operation LTC3703-5 to drive multiple MOSFETs for higher current ■ Low Shutdown Current: 25µA Typ applications. The operating frequency is user program- ■ Programmable Current Limit mable from 100kHz to 600kHz and can also be synchro- ■ Undervoltage Lockout nized to an external clock for noise-sensitive applications. ■ Programmable Soft-Start Current limit is programmable with an external resistor ■ 16-Pin Narrow SSOP and 28-Pin SSOP Packages U and utilizes the voltage drop across the synchronous APPLICATIO S MOSFET to eliminate the need for a current sense resistor. For applications requiring up to 100V operation, refer to ■ 48V Telecom and Base Station Power Supplies the LTC3703 data sheet. ■ Networking Equipment, Servers PARAMETERLTC3703-5LTC3703 ■ Automotive and Industrial Control Maximum VIN 60V 100V MOSFET Gate Drive 4.5V to 15V 9.3V to 15V , LTC and LT are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. VCC UV+ 3.7V 8.7V *U.S. Patent Numbers: 5408150, 5055767, 6677210, 5847554, 5481178, 6304066, 6580258; Others Pending. VCC UV– 3.1V 6.2V UTYPICAL APPLICATIOHigh Efficiency High Voltage Step-Down Converter VCC 5V Efficiency vs Load Current + VIN 22µF 100 6V TO 60V MMDL770T1 MODE/SYNC VIN + VIN = 12V V 22µF IN = 24V 30k 95 FSET BOOST ×2 ) 10k Si7850DP % COMP TG V 0.1µF IN = 42V 1000pF 470pF LTC3703-5 90 FB SW 8µH VOUT 21.5k 12k 5V EFFICIENCY ( 1% I 5A MAX VCC 10Ω + 270µF 85 INV DRV 16V CC 0.1µF Si7850DP RUN/SS BG D1 10µF 80 MBR1100 100Ω 113k 0 1 2 3 4 5 GND BGRTN 1% LOAD CURRENT (A) 1µF 2200pF 37053 TA04b 37035 TA04 37035fa 1