Datasheet LTC3703-5 (Analog Devices) - 8

LTC3703-5
U U W FU CTIO AL DIAGRA
RSET FSET 2 OVERCURRENT 12µA 4µA IMAX – 5 + RMAX 50mV – ± + RUN/SS 5 – ± INV CHIP CSS 1V + SD 3.2V UVSD OTSD V EXT SYNC + CC SYNC MODE/SYNC 1 OSC DETECT – DB REVERSE BOOST V FORCED CONTINUOUS INV IN 15 CURRENT COMP TG CB 3 14 M1 SW – 13 DRIVE + 0.8V % DC PWM FB + FB + LOGIC ÷ DRV LIMIT CC 4 – 11 BG V 16 10 IN M2 R2 R1 MIN MAX + – + – BGRTN 9 6 INV VCC 0.76V 0.84V (<15V) 12 L1 OVER BANDGAP V 8 GND V TEMP CC UVLO OUT COUT OT SD 0.8V INTERNAL UV SD REFERENCE 3.2V VCC GN16 VCC CVCC 37035 FD
U OPERATIO (Refer to Functional Diagram)
The LTC3703-5 is a constant frequency, voltage mode Diagram of the IC and the circuit on the first page of this controller for DC/DC step-down converters. It is designed data sheet. The LTC3703-5 uses voltage mode control in to be used in a synchronous switching architecture with which the duty ratio is controlled directly by the error two external N-channel MOSFETs. Its high operating volt- amplifier output and thus requires no current sense resis- age capability allows it to directly step down input voltages tor. The VFB pin receives the output voltage feedback and up to 60V without the need for a step-down transformer. is compared to the internal 0.8V reference by the error For circuit operation, please refer to the Functional amplifier, which outputs an error signal at the COMP pin. 37035fa 8