Adding to their ever growing family of power supply regulators Linear Technology have introduced the LTC3807 step-down switching regulator DC/DC controller driving an all N-channel external synchronous power MOSFET stage. The chip uses a constant frequency current mode architecture allowing a phase-lockable frequency of up to 750 kHz.
The chip draws just 50 μA no-load quiescent current and an OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3807 features a precision 0.8 V reference and power-good output indicator.
The TRACK/SS pin ramps the output voltages during start-up. Current foldback limits the MOSFET heat dissipation during short-circuit conditions. The PLLIN/MODE pin selects either burst-mode operation, pulse-skipping or continuous conduction mode at light loads.
LTC3807 main features:
- Wide VIN range: 4 V to 38 V (40V abs max)
- Low operating IQ: 50 μA
- Wide output voltage range: 0.8 V ≤ VOUT ≤ 24 V
- RSENSE or DCR current sensing
- Phase-lockable frequency (75 kHz to 750 kHz)
- Programmable fixed frequency (50 kHz to 900 kHz)
- Selectable continuous, pulse-skipping or low ripple burst mode operation at light load
- Selectable current limit
- Very low dropout operation: 99% duty cycle
- Adjustable output voltage soft-start or tracking
- Power good output voltage monitor
- Output overvoltage protection
- Low shutdown IQ: 14 μA
- Internal LDO powers gate drive from VIN or EXTVCC
- No current foldback during start-up
The LTC 3807 is available in 20-pin 3 × 4 mm QFN and TSSOP packages