42V, Low I, Quad Output Triple Monolithic Buck Converter and Boost Controller

The LT8603 is a highly flexible, quad output regulator combining two high input voltage capable monolithic step-down switching regulators, one low input voltage capable monolithic step-down regulator, and a boost controller to satisfy a wide range of applications while occupying minimal board space.

With the boost controller configured to supply the chip VIN supply, the LT8603 produces three precisely regulated outputs even when the boost input voltage falls significantly below the regulated output voltages, such as during an automotive cold crank scenario. Alternatively, with the boost controller driven from one of the step-down regulator outputs or configured as a SEPIC, the LT8603 provides four precisely regulated outputs over a wide input voltage range.

The LT8603 provides robust regulation by including a cycle-by-cycle current limit for all step-down regulators, thermal shutdown, and a boost controller that can tolerate reverse battery connections and negative transient input voltages down to –42V.

Applications

* Automotive Stop-Start and Cold Crank Ride Through

* Last-Gasp CPU Power Hold-Up

* Industrial Controls and Power Supplies

* Flexible Power Supply System Capable of Four Regulated Outputs with VBATT << VOUT

* Two High Voltage Synchronous Buck Regulators

* 3V to 42V Input Voltage Range

* Output Currents Up to 2.5A and 1.5A

* One Low Voltage Synchronous Buck Regulator

* 2.6V to 5.5V Input Voltage Range

* Output Currents Up to 1.8A

* One Boost Controller Allows Buck Converters to Regulate with VBATT << VOUT