Dual Monolithic 1.4A Step-Down Switching Regulator

The LT3508 is a dual current mode PWM step-down DC/DC converter with internal power switches capable of generating two 1.4A outputs. The wide input voltage range of 3.7V to 36V makes the LT3508 suitable for regulating power from a wide variety of sources, including automotive batteries, 24V industrial supplies and unregulated wall adapters. Both converters are synchronized to a single oscillator programmable up to 2.5MHz and run with opposite phases, reducing input ripple current. Its high operating frequency allows the use of small, low cost inductors and ceramic capacitors, resulting in low, predictable output ripple. Each regulator has independent tracking and soft-start circuits and generates a power good signal when its output is in regulation, easing power supply sequencing and interfacing with microcontrollers and DSPs.

Cycle-by-cycle current limit, frequency foldback and thermal shutdown provide protection against shorted outputs, and soft-start eliminates input current surge during startup. The low current (<2µA) shutdown mode enables easy power management in battery-powered systems.

Applications

* Automotive

* DSP Power Supplies

* Wall Transformer Regulation

* DSL and Cable Modems

* PCI Express

* Wide Input Voltage Range: 3.7V to 36V

* Two 1.4A Output Switching Regulators with Internal Power Switches

* Adjustable 250kHz to 2.5MHz Switching Frequency

* Synchronizable over the Full Frequency Range

* Anti-Phase Switching Reduces Ripple

* Uses Small Inductors and Ceramic Capacitors