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LM21215
May 31, 2011
15A High Efficiency Point of Load Synchronous Buck
Regulator
General Description
The LM21215 is a monolithic synchronous point of load buck
regulator that is capable of delivering up to 15A of continuous
output current while producing an output voltage down to 0.6V
with outstanding efficiency. The device is optimized to work
over an input voltage range of 2.95V to 5.5V, making it suited
for a wide variety of low voltage systems. The voltage mode
control loop provides high noise immunity, narrow duty cycle
capability and can be compensated to be stable with any type
of output capacitance, providing maximum flexibility and ease
of use.
The LM21215 features internal over voltage protection (OVP)
and resistor-programmable over-current protection (OCP) for
increased system reliability. A precision enable pin and inte-
grated UVLO allow turn-on of the device to be tightly con-
trolled and sequenced. Startup 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.
The LM21215 is designed to work well in multi-rail power
supply architectures. The output voltage of the device can be
configured to track an external voltage rail using the SS/TRK
pin. If the output is pre-biased at startup, it will not sink current,
allowing the output to smoothly rise past the pre-biased volt-
age. The regulator is offered in a 20-pin eTSSOP package
with an exposed pad that can be soldered to the PCB, elimi-
nating the need for bulky heatsinks.
Features
■ Integrated 7.0 m high side and 4.3 m low side FET
switches
■ Adjustable current limit
■ Adjustable output voltage from 0.6V to V
IN (100% duty
cycle capable), ±1% reference
■ Input voltage range 2.95V to 5.5V
■ 500 kHz fixed switching frequency
■ Startup into pre-biased loads
■ Output voltage tracking capability
■ Wide bandwidth voltage loop error amplifier
■ Adjustable soft-start with external capacitor
■ Precision enable pin with hysteresis
■ Integrated OVP, OTP, UVLO and Power-Good
■ Thermally Enhanced eTSSOP-20 exposed pad package
Applications
■ Broadband, networking and wireless communications
■ High-performance FPGAs, ASICs and microprocessors
■ Simple to design, high efficiency point of load regulation
from a 5V or 3.3V bus
Simplified Application Circuit
30103701
PowerWise is a registered trademark of National Semiconductor Corporation.
2011 National Semiconductor Corporation
301037
www.national.com
LM21215
15A
High
Efficiency
Synchronous
Buck
Regulator