Texas Instruments TPS546B25/TPS546B25W Synchronous Buck Converters

Texas Instruments TPS546B25/TPS546B25W Synchronous Buck Converters are highly integrated, stackable buck converters with D-CAP4 control topology for fast transient response. These converters support an input voltage range of 4V to 18V (down to 2.7V with external bias) and offer single-phase or stacked configurations of 2x, 3x, or 4x. The TPS546B25/TPS546B25W converters feature PMBus 1.5 compliance and offer extensive telemetry, including voltage, current, and temperature. These buck converters operate within a 400kHz to 2MHz operating frequency range (four discrete settings via a pin-strap, with additional settings available through PMBus^®). Additional features include programmable internal loop compensation, selectable cycle-by-cycle valley current limit, and open-drain power-good output. The TPS546B25/TPS546B25W buck converters are lead-free devices and are RoHS compliant without exemption. Typical applications include servers and cloud computing POLs, hardware accelerators, and Network Interface Cards (NICs).

Features

2.7V to 18V input voltage range with external bias
4V to 18V input voltage range without external bias
0.4V to 5.5V output voltage range
Supports 25A single-phase or 2 x, 3 x, or 4 x stacked configurations
Rds_{on_HS} = 2.6mΩ, Rds_{on_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% V_OUT 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