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.