1 Features

1• Integrated 26 mΩ / 19 mΩ MOSFETs

• Split Power Rail: 1.6 V to 17 V on PVIN

• 200 kHz to 1.6 MHz Switching Frequency

• Synchronizes to External Clock

• 0.6V ±1% Voltage Reference Over Temperature

• Low 2 μA Shutdown Quiescent Current

• Monotonic Start-Up into Pre-biased Outputs

• Adjustable Slow Start/Power Sequencing

• Power Good Output Monitor for Undervoltage and

Overvoltage

• Adjustable Input Undervoltage Lockout

• Software Tools Available

2 Applications

• Digital TV Power Supplies

• Set Top Boxes

• Blu-ray DVDs

• Home Terminals

• High Performance Point of Load Regulation

3 Description

The TPS54821 in thermally enhanced 3.5 mm x 3.5

mm QFN package is a full featured 17 V, 8 A

synchronous step down converter which is optimized

for small designs through high efficiency and

integrating the high-side and low-side MOSFETs.

Further space savings are achieved through current

mode control, which reduces component count, and

by selecting a high switching frequency, reducing the

inductor's footprint.

The output voltage startup ramp is controlled by the

SS/TR pin which allows operation as either a stand

alone power supply or in tracking situations. Power

sequencing is also possible by correctly configuring

the enable and the open drain power good pins.

Cycle by cycle current limiting on the high-side FET

protects the device in overload situations and is

enhanced by a low-side sourcing current limit which

prevents current runaway. There is also a low-side

sinking current limit which turns off the low-side

MOSFET to prevent excessive reverse current.

Hiccup protection will be triggered if the overcurrent

condition has persisted for longer than the preset

time. Thermal hiccup protection disables the device

when the die temperature exceeds the thermal

shutdown temperature and enables the part again

after the built-in thermal shutdown hiccup time.