High Efficiency, 2-Phase Synchronous Step-Down Switching Regulators

The LTC3727A-1 is a high performance dual step-down switching regulator controller that drives all N-channel synchronous power MOSFET stages. A constant frequency current mode architecture allows phase-lockable frequency of up to 550kHz. Power loss and noise due to the ESR of the input capacitors are minimized by operating the two controller output stages out of phase.

The LTC3727A-1 is an improved version of the LTC3727 family of parts. It has smaller output ripple while in the drop-out condition and shorter minimum on-time.

OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. There is a precision 0.8V reference and a power good output indicator. A wide 4V to 30V (36V maximum) input supply range encompasses all battery chemistries.

A RUN/SS pin for each controller provides soft-start. Current foldback limits MOSFET heat dissipation during short-circuit conditions. Output overvoltage protection circuitry protects the controller until VOUT returns to normal.

VIN Range

VREF Accuracy Over Temp

Latch-Off

Min On-Time

LTC3727

4V - 36V

±1%

No

180ns

LTC3727-1

4V - 36V

±1%

Yes

180ns

LTC3727A-1

4V - 36V

±1%

No

120ns

LTC3727LX-1

4V - 32V

±1.5%

No

120ns

Applications

* Telecom Systems

* Automotive Systems

* Battery-Operated Digital Devices

* Wide Output Voltage Range: 0.8V ≤ VOUT ≤ 14V

* Out-of-Phase Controllers Reduce Required Input Capacitance and Power Supply Induced Noise

* OPTI-LOOP® Compensation Minimizes COUT

* ±1% Output Voltage Accuracy

* Power Good Output Voltage Monitor

* Phase-Lockable Fixed Frequency 250kHz to 550kHz

* Dual N-Channel MOSFET Synchronous Drive