LTC3703 FuncTional DiagraM RSET 2 GN16 fSET OVERCURRENT 12µA 4µA IMAX – 5 + RMAX 50mV – ± + RUN/SS 5 – ± CHIP INV CSS 0.9V + SD 3.2V UVSD OTSD EXT SYNC V + CC MODE/SYNC SYNC 1 DETECT OSC – DB FORCED CONTINUOUS V INV REVERSE BOOST IN 15 CURRENT C COMP TG B 3 14 M1 – SW DRIVE 13 0.8V + % DC PWM + FB FB ÷ + LOGIC LIMIT DRVCC 4 – 11 V BG 16 IN 10 R2 R1 M2 + – MIN + – MAX BGRTN 9 INV 6 VCC 0.76V 0.84V (<15V) 12 L1 VOUT OVER GND BANDGAP C TEMP VCC UVLO 8 OUT OT SD 0.8V INTERNAL UV SD REFERENCE 3.2V VCC VCC CVCC 3703 FD operaTion (Refer to Functional Diagram) The LTC3703 is a constant frequency, voltage mode con- of the IC and Figure 1. The LTC3703 uses voltage mode troller for DC/DC step-down converters. It is designed to control in which the duty ratio is controlled directly by be used in a synchronous switching architecture with two the error amplifier output and thus requires no current external N-channel MOSFETs. Its high operating voltage sense resistor. The VFB pin receives the output voltage capability allows it to directly step down input voltages up feedback and is compared to the internal 0.8V reference to 100V without the need for a step-down transformer. For by the error amplifier, which outputs an error signal at the circuit operation, please refer to the Functional Diagram COMP pin. When the load current increases, it causes a 3703fc 8 Document Outline Features Description Applications Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Functional Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts