LTC3857EUH#PBF

LTC3857 is a high performance dual step-down switching regulator controller. It drives all N-channel synchronous power MOSFET stages. A constant frequency current mode architecture allows a phase-lockable frequency of upto 850KHz. Power loss and noise due to the ESR of the input capacitor ESR are minimized by operating the two controller output stages out of phase. Independent TRACK/SS pins for each controller ramp the output voltages during start-up. Current foldback limits MOSFET heat dissipation during short-circuit conditions. The PLLIN/MODE pin selects among Burst Mode operation, pulse-skipping mode, or continuous inductor current mode at light loads. It is widely used in application such as automotive always-on systems, battery operated digital devices, distributed DC power systems etc.

• Input supply operating voltage range is 4V to 38V
• RSENSE or DCR current sensing, output overvoltage protection
• OPTI-LOOP® compensation minimizes COUT
• Selectable current limit, very low dropout operation: 99% duty cycle
• Adjustable output voltage soft-start or tracking
• Power good output voltage monitors
• Internal LDO powers gate drive from VIN or EXTVCC
• Low operating current (one channel on) is 50μA typ at (RUN1 = 5V and RUN2 = 0V, VFB1 = 0.83V)
• Shutdown current is 8μA typical at (RUN1, 2 = 0V, TA = 25°C)
• Operating junction temperature is -40°C to 125°C, package style is 32-lead plastic QFN

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