TPS54821_16 Datasheet, PDF (1/42 Pages) Texas Instruments – 4.5 V to 17 V Input, 8 A Synchronous Step Down Converter

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TPS54821
SLVSB14B – OCTOBER 2011 – REVISED FEBRUARY 2016
TPS54821 4.5 V to 17 V Input, 8 A Synchronous Step Down Converter With Hiccup
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.
Simplified Schematic
VIN
Cin
Css Rrt C2
PVIN
VIN
TPS54821
BOOT
Cboot
Lo
EN
PH
Co
PWRGD
SS/TR ^VSENSE
RT/CLK
COMP GND
R3
Exposed
Thermal
C1
Pad
VOUT
R1
R2
Device Information⁽¹⁾
PART NUMBER
PACKAGE
BODY SIZE (NOM)
TPS54821
VQFN (14)
3.50 mm x 3.50 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
Efficiency, V_OUT = 3.3 V, F_SW = 480 kHz
100
90
80
70
60
50
40
30
20
V_IN = 8 V
10
V_IN = 12 V
V_IN = 17 V
0
0
1
2
3
4
5
6
7
8
Output Current (A)
G001
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.