Quad 40V/1A Step-Down Switching Regulator with 100% Duty Cycle Operation

The LT3504 consists of four 1A output current buck regulators. The LT3504 has a wide operating input range of 3.2V to 40V. An on-chip boost regulator allows each channel to operate up to 100% duty cycle and eliminates the need for four external charge pump circuits. The LT3504 is designed to minimize external component count and results in a simple and small application circuit.

The LT3504 operates robustly in fault conditions. Cycle-by-cycle peak current limit and catch diode current limit sensing protect the part during overload conditions. Thermal shutdown protects the power switches at elevated temperatures. Soft-start helps keep the peak inductor current under control during startup.

The LT3504 also features output voltage tracking and sequencing, programmable frequency, programmable undervoltage lockout, and a power good pin to indicate when all outputs are in regulation.

Applications

* Automotive Battery Regulation

* Industrial Control Supplies

* Wall Transformer Regulation

* Distributed Supply Regulation

* Wide Input Range: 3.2V to 40V

* Four 1A Outputs

* 100% Duty Cycle Operation

* Resistor-Programmed Constant Frequency

* Short-Circuit Robust

* Wide SYNC Range: 350kHz to 2.2MHz

* Anti-Phase Switching Reduces Ripple

* 800mV FB Voltage

* Independent Run/Soft-Start Pins

* Shutdown with UVLO

* Internal Compensation

* Thermal Shutdown

* Tiny 28-Lead (4mm × 5mm) Thermally Enhanced QFN Package