4V to 18V input, 25A, stackable, PMBus synchronous step-down converter

The TPS546B25 device

is a highly-integrated buck converter with D-CAP4 control topology for

fast transient response. All programmable

parameters can be configured by the PMBus interface and stored in NVM as the new

default values to minimize the external component count. Pin-strap options

allow for configuration as primary or secondary,

stack position and stack number, DCM (single phase only) or FCCM, overcurrent limit, fault response, internal

or external feedback resistor, output voltage selection or range, switching

frequency, and compensation.

The PMBus

interface with 1MHz clock support gives a convenient, standardized, digital

interface for configuration as well as telemetry of key parameters including

output voltage, output current, and internal die temperature. Response to

fault conditions can be set to restart, latch off, or ignore, depending on system

requirements. Two, three, and four TPS546B25 devices can be interconnected to provide

up to 100A on a single output.

The TPS546B25 has an

option to overdrive the internal 4.5V LDO with an external 5V supply through the VDRV and VCC pins to improve efficiency, reduce power dissipation, and

enable start-up with a lower input voltage.

The TPS546B25 is a lead-free device and is RoHS compliant without exemption.