Datasheet
PVIN
SW
AGND
FB
PGOOD
EN
SS/TRK
AVIN
COMP
LM20145
L
R
F
VCC
PGND
C
IN
R
C1
C
C1
V
IN
C
SS
C
VCC
C
OUT
V
OUT
R
FB2
R
FB1
C
F
RT
R
T
(optional)
LM20145
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SNVS530E –OCTOBER 2007–REVISED MARCH 2013
LM20145/LM20145Q 5A, PowerWise
®
Adjustable Frequency Synchronous Buck Regulator
Check for Samples: LM20145
1
FEATURES
DESCRIPTION
The LM20145 is a full featured adjustable frequency
2
• Available in AEC-Q100 Temperature Grade 1
synchronous buck regulator capable of delivering up
• Input Voltage Range 2.95V to 5.5V
to 5A of continuous output current. The current mode
• Accurate Current Limit Minimizes Inductor
control loop can be compensated to be stable with
Size
virtually any type of output capacitor. For most cases,
compensating the device only requires two external
• 97% Peak Efficiency
components, providing maximum flexibility and ease
• Adjustable Switching Frequency (250 kHz to
of use. The device is optimized to work over the input
750 kHz)
voltage range of 2.95V to 5.5V making it suited for a
• 32 mΩ Integrated FET Switches
wide variety of low voltage systems.
• Starts up into Pre-Biased Loads
The device features internal over voltage protection
(OVP) and over current protection (OCP) circuits for
• Output Voltage Tracking
increased system reliability. A precision enable pin
• Peak Current Mode Control
and integrated UVLO allows the turn-on of the device
• Adjustable Output Voltage down to 0.8V
to be tightly controlled and sequenced. Start-up
• Adjustable Soft-Start with External Capacitor
inrush currents are limited by both an internally fixed
and externally adjustable Soft-Start circuit. Fault
• Precision Enable Pin with Hysteresis
detection and supply sequencing is possible with the
• Integrated OVP, UVLO, Power Good and
integrated power good circuit.
Thermal Shutdown
The LM20145 is designed to work well in multi-rail
• HTSSOP 16-Pin Exposed Pad Package
power supply architectures. The output voltage of the
device can be configured to track a higher voltage rail
APPLICATIONS
using the SS/TRK pin. If the output of the LM20145 is
pre-biased at startup it will not sink current to pull the
• Simple to Design, High Efficiency Point of
output low until the internal soft-start ramp exceeds
Load Regulation from a 5V or 3.3V Bus
the voltage at the feedback pin.
• High Performance DSPs, FPGAs, ASICs and
The frequency of this device can be adjusted from
Microprocessors
250 kHz to 750 kHz by connecting an external
• Broadband, Networking and Optical
resistor from the RT pin to ground.
Communications Infrastructure
The LM20145 is offered in a 16-pin HTSSOP
package with an exposed pad that can be soldered to
the PCB, eliminating the need for bulky heatsinks.
Typical Application Circuit
1
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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
2All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Copyright © 2007–2013, Texas Instruments Incorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.