The LT®3501 is a dual, current mode PWM step-down DC/DC converter with two internal 3.5A switches. Independent input voltage, feedback, soft-start and power good pins for each channel simplify complex power supply tracking/sequencing requirements.

Both converters are synchronized to a common external clock input or to a fixed 250kHz to 1.5MHz internal oscillator programmable with a single resistor. A 180° phase relationship is maintained between the two channels at all frequencies, reducing voltage ripple and component size. Programmable frequency enables optimization between efficiency and external component size. A maximum duty cycle of approximately 95% is achieved by allowing the switch to remain on for multiple clock cycles (turning off only when the boost capacitor needs to be recharged) to improve the minimum input-to-output voltage ratio. Each output can be independently disabled using its own soft-start pin, or the entire device can be placed in a low quiescent current shutdown mode using the SHDN pin. The LT3501 is available in a 20-pin TSSOP package with exposed leadframe for low thermal resistance.

 

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