LTC3731 PIN FUNCTIONSVCC: Main Supply Pin. This pin supplies the controller VDR: (LTC3731G Package Only) Supplies power to the circuit power. In the LTC3731 UH package, it also supplies bottom gate drivers only. This pin needs to be very care- the high power pulses to drive the external MOSFET gates. fully and closely decoupled to the IC’s PGND pin. This pin needs to be very carefully and closely decoupled to the IC’s PGND pin. FUNCTIONAL DIAGRAM PLLIN F PHASE DET IN 50k PLLFLTR RLP CLP CLKOUT CLK1 OSCILLATOR CLK2 PHASMD** CLK3 DUPLICATE FOR SECOND AND THIRD VCC VIN PGOOD** – 0.66V CONTROLLER CHANNELS D + BOOST B 100µs EAIN DELAY DROP – OUT PROTECTION + 0.54V DET TG CB BOT TOP + FCB FORCE BOT CIN + S Q RS – FCB LATCH SWITCH SW 0.6V R Q LOGIC IN– 40k 40k VCC (VDR)*** BG B BOT – 0.55V FCB A1 PGND + IN+ SHDN 40k 40k – – L I1 – + + – I2 V DIFFOUT + CC + SENSE+ 3mV 36k SLOPE R1 COMP RSENSE C EAIN V SENSE– FB 5(V OUT FB) 36k – 0.86V EA + R2 0.600V + SS 54k 54k VOUT CLAMP OV 2.4V + 0.660V – FCB ITH SHED 1.2V VREF 0.600V V C CC C V VCC SHDN CC RUN INTERNAL RC 1.5µA RST SOFT- SUPPLY + 5(VFB) START SGND* CCC 6V UV RESET UVADJ RUN/SS – 1.2V + CSS 3731 F02 *THE LTC3731UH USES THE EXPOSED DIE ATTACH PAD FOR THE SGND CONNECTIONS **THE PHASMD AND PGOOD PIN FUNCTIONS ARE TIED TOGETHER IN THE LTC3731 UH PACKAGE ***LTC3731CG/IG ONLY Figure 2 3731fc 10 Document Outline Features Applications Features Description 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