LM22674 500 mA SIMPLE SWITCHER®, Step-Down Voltage Regulator with Precision Enable
December 18, 2009
LM22674
500 mA SIMPLE SWITCHER®, Step-Down Voltage
Regulator with Precision Enable
General Description
The LM22674 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 500
mA loads with excellent line and load regulation characteris-
tics. 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 LM22674 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
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Wide input voltage range: 4.5V to 42V
Internally compensated voltage mode control
Stable with low ESR ceramic capacitors
200 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
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PSOP-8 (Exposed Pad)
Applications
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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
30076901
© 2009 National Semiconductor Corporation
300769
www.national.com
NSC [ NATIONAL SEMICONDUCTOR ]
