LM22678 Datasheet, PDF (1/16 Pages) National Semiconductor (TI) – 5A SIMPLE SWITCHER®, Step-Down Voltage Regulator with Precision Enable

LM22678
December 18, 2009
5A SIMPLE SWITCHER®, Step-Down Voltage Regulator
with Precision Enable
General Description
The LM22678 series of regulators are monolithic integrated
circuits which provide all of the active functions for a step-
down (buck) switching regulator capable of driving up to 5A
loads with excellent line and load regulation characteristics.
High efficiency (>90%) is obtained through the use of a low
ON-resistance N-channel MOSFET. The series consists of a
fixed 5V output and an adjustable version.
The SIMPLE SWITCHER^® concept provides for an easy to
use complete design using a minimum number of external
components and National’s WEBENCH^® design tool.
National’s WEBENCH^® tool includes features such as exter-
nal component calculation, electrical simulation, thermal sim-
ulation, and Build-It boards for easy design-in. The switching
clock frequency is provided by an internal fixed frequency os-
cillator which operates at 500 kHz. The LM22678 series also
has built in thermal shutdown, current limiting and an enable
control input that can power down the regulator to a low 25
µA quiescent current standby condition.
Features
■ ^{Wide input voltage range: 4.5V to 42V}
■ ^{Internally compensated voltage mode control}
■ ^{Stable with low ESR ceramic capacitors}
■ ^{100 mΩ N-channel MOSFET}
■ ^{Output voltage options:}
-ADJ (outputs as low as 1.285V)
-5.0 (output fixed to 5V)
■ ^{±1.5% feedback reference accuracy}
■ ^{Switching frequency of 500 kHz}
■ ^{-40°C to 125°C operating junction temperature range}
■ ^{Precision enable pin}
■ ^{Integrated boot diode}
■ ^{Integrated soft-start}
■ ^{Fully WEBENCH® enabled}
■ ^{Step-down and inverting buck-boost applications}
Package
■ ^{TO-263 THIN (Exposed Pad)}
Applications
■ ^{Industrial Control}
■ ^{Telecom and Datacom Systems}
■ ^{Embedded Systems}
■ ^{Automotive Telematics and Body Electronics}
■ ^{Conversions from Standard 24V, 12V and 5V Input Rails}
Simplified Application Schematic
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