1 Features

• 2.7V to 18V input voltage with external bias

• 4V to 18V input voltage without external bias

• 0.4V to 5.5V output voltage

• Supports 25A single-phase or 2 ×, 3 ×, or 4 ×

stacked configurations

• Rdson_HS = 2.6mΩ, Rdson_LS = 1mΩ

• 400kHz to 2MHz operating frequency (four

discrete settings through pin-strap, additional

settings through PMBus®)

• PMBus programmable

– Revision 1.5 compliant with PASSKEY security

feature

– Input voltage, output voltage, output current,

temperature telemetry

– Programmable overcurrent, overvoltage,

undervoltage, overtemperature protections

– Includes single command write function in

stacked configuration

– Extended write protection feature

– Non-volatile memory to store configuration

settings

• Two methods for programming the output voltage

– Internal resistor divider (discrete settings) with

boot-up voltage selected by pin-strapping

– External resistor divider (continuous settings)

with boot-up voltage selected by VBOOT

• Precision voltage reference and differential remote

sense for high output accuracy

– ± 0.5% DAC accuracy from 0°C to 85°C

junction

– ± 0.85% VOUT tolerance from –40°C to 125°C

junction

• Selectable FCCM/DCM in single phase only

• Start-up without PMBus communication through

pin-strapping

• Safe start-up into prebiased output

• 0.5ms to 16ms programmable soft-start time

• D-CAP4 control topology with fast transient

response, supporting all ceramic output capacitors

• Programmable internal loop compensation

• Selectable cycle-by-cycle valley current limit

• Open-drain power-good output

2 Applications

• Server and cloud-computing POLs

• Hardware accelerator

• Network interface card (NIC)

3 Description

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.