TPS54821 Datasheet, PDF (1/37 Pages) Texas Instruments – 4.5 V to 17 V Input, 8 A Synchronous Step Down SWIFT™ Converter With Hiccup

TPS54821
www.ti.com
SLVSB14 – OCTOBER 2011
4.5 V to 17 V Input, 8 A Synchronous Step Down SWIFT™ Converter With Hiccup
Check for Samples: TPS54821
FEATURES
1
•23 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
• –40°C to 125°C Operating Junction
Temperature Range
• Adjustable Slow Start/Power Sequencing
• Power Good Output Monitor for Undervoltage
and Overvoltage
• Adjustable Input Undervoltage Lockout
• Software Tools Available
• For SWIFT™ Documentation visit
http://www.ti.com/swift
APPLICATIONS
• Digital TV Power Supplies
• Set Top Boxes
• Blu-ray DVDs
• Home Terminals
• High Performance Point of Load Regulation
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.
WHITE SPACE
SIMPLIFIED SCHEMATIC
VIN
Cin
Css Rrt C2
PVIN
VIN
TPS54821
BOOT
Cboot
EN
PH
PWRGD
Lo
Co
SS/TR ^VSENSE
RT/CLK
COMP GND
R3
Exposed
Thermal
C1
Pad
VOUT
R1
R2
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
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
SWIFT is a trademark of Texas Instruments.
2
All other trademarks are the property of their respective owners.
3
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2011, Texas Instruments Incorporated