February 12, 2009
LM20146
6A, Adjustable Frequency Synchronous Buck Regulator
General Description
Features
The LM20146 is a full featured adjustable frequency syn-
chronous buck regulator capable of delivering up to 6A of
continuous output current. The current mode control loop can
be compensated to be stable with virtually any type of output
capacitor. For most cases, compensating the device only re-
quires two external components, providing maximum flexibil-
ity and ease of use. The device is optimized to work over the
input voltage range of 2.95V to 5.5V making it suitable for a
wide variety of low voltage systems.
Input voltage range 2.95V to 5.5V
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Accurate current limit minimizes inductor size
97% peak efficiency
Adjustable switching frequency (250 kHz to 750 kHz)
16mΩ and 20mΩ integrated FET switches
Starts up into pre-biased loads
Output voltage tracking
Peak current mode control
The device features internal over voltage protection (OVP)
and over current protection (OCP) circuits for increased sys-
tem reliability. A precision enable pin and integrated UVLO
allows the turn-on of the device to be tightly controlled and
sequenced. Start-up inrush currents are limited by both an
internally fixed and externally adjustable Soft-Start circuit.
Fault detection and supply sequencing are possible with the
integrated power good circuit.
Adjustable output voltage down to 0.8V
Adjustable Soft-Start with external capacitor
Precision enable pin with hysteresis
Integrated OVP, UVLO, power good and thermal
shutdown
eTSSOP-16 exposed pad package
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The LM20146 is designed to work well in multi-rail power
supply architectures. The output voltage of the device can be
configured to track a higher voltage rail using the SS/TRK pin.
If the output of the LM20146 is pre-biased at startup it will not
pull the ouput low.
Applications
Simple to design, high efficiency point of load regulation
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from a 5V or 3.3V bus
High Performance DSPs, FPGAs, ASICs and
microprocessors
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The frequency of this device can be adjusted from 250 kHz to
750 kHz by connecting an external resistor from the RT pin to
ground.
Broadband, Networking and Optical Communications
Infrastructure
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The LM20146 is offered in a 16-pin eTSSOP package with an
exposed pad that can be soldered to the PCB, eliminating the
need for bulky heatsinks.
Typical Application Circuit
30053801
®
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