TPS54478 Datasheet, PDF (1/37 Pages) Texas Instruments – 2.95-V to 6-V Input, 4-A Output, 2-MHz, Synchronous Step-Down

TPS54478
www.ti.com
SLVSAS2 – JUNE 2011
2.95-V to 6-V Input, 4-A Output, 2-MHz, Synchronous Step-Down
Switcher With Integrated FETs ( SWIFT™)
Check for Samples: TPS54478
FEATURES
1
•2 Two 30-mΩ (typical) MOSFETs for High
Efficiency at 4 A Loads
• 200kHz to 2MHz Switching Frequency
• 0.6 V ± 1% Voltage Reference Over
Temperature (–40°C to 150°C)
• Start up with Pre-Biased Voltage
• Synchronizes to External Clock
• Adjustable Slow Start / Sequencing
• UV and OV Power Good Output
• Cycle by Cycle Current Limit and Hiccup
Current Protection
• Thermally Enhanced 3mm × 3mm 16-pin QFN
(RTE)
• Pin Compatible to TPS54418
APPLICATIONS
• Low-Voltage, High-Density Power Systems
• Point of Load Regulation for High Performance
DSPs, FPGAs, ASICs and Microprocessors
• Broadband, Networking and Optical
Communications Infrastructure
SIMPLIFIED SCHEMATIC
vertical spacer
vertical spacer
VIN
CI
C ss
RT
VIN
C_BOOT
BOOT
R4
TPS54478
LO
EN
PH
R5
CO
PWRGD
VSENSE
SS/TR
RT /CLK
COMP
GND
AGND
POWERPAD
R3
C1
VOUT
R1
R2
DESCRIPTION
The TPS54478 device is a full featured 6 V, 4 A,
synchronous step down current mode converter with
two integrated MOSFETs.
The TPS54478 enables small designs by integrating
the MOSFETs, implementing current mode control to
reduce external component count, reducing inductor
size by enabling up to 2 MHz switching frequency,
and minimizing the IC footprint with a small 3mm x
3mm thermally enhanced QFN package.
The TPS54478 provides accurate regulation for a
variety of loads with an accurate ±1% Voltage
Reference (VREF) over temperature.
Efficiency is maximized through the integrated 30mΩ
MOSFETs and 525μA typical supply current. Using
the enable pin, shutdown supply current is reduced to
2.5µA by entering a shutdown mode.
Under voltage lockout is internally set at 2.6 V, but
can be increased by programming the threshold with
a resistor network on the enable pin. The output
voltage startup ramp is controlled by the slow start
pin. An open drain power good signal indicates the
output is within 93% to 107% of its nominal voltage.
Cycle-by-cycle current limit, hiccup overcuurent
protection and thermal shutdown protect the device
during an overcurrent condition.
The TPS54478 is supported in the SwitcherPro™
Software Tool at www.ti.com/switcherpro.
For more SWIFT^TM documentation, see the TI
website at www.ti.com/swift.
95
90
85
V_IN = 5 V
80
V_IN = 3.3 V
75
70
65
60
F_S = 1 MHz,
DCR = 6.8 mW,
55
V_O = 1.8 V
50
0
0.5
1
1.5
2
2.5
3
3.5
4
I_O - Output Current - A
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, SwitcherPro are trademarks of Texas Instruments.
2
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