National Semiconductor LM22679 Data Handbook
Summary
This high-efficiency step-down voltage regulator is designed for reliable power conversion in demanding applications, accommodating wide input voltages (4.5V to 42V) while offering advanced features like adjustable soft-start and precise current limit control. The comprehensive manual guides engineers through design implementation, detailing electrical characteristics, operating ratings, life support guidelines, and utilizing resources such as the WEBENCH tool. It is ideal for designers developing industrial, telecom, datacom, embedded, or automotive electronics systems requiring stable power rails from standard input sources.
Page 1 Text Content
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October 17, 2008
LM22679 5A SIMPLE SWITCHER®, Step-Down Voltage Regulator with Adjustable Soft-Start and Current Limit General Description Features The LM22679 series of regulators are monolithic integrated Wide input voltage range: 4.5V to 42V circuits which provide all of the active functions for a step-
Internally compensated voltage mode control
down (buck) switching regulator capable of driving up to 5A
Stable with low ESR ceramic capacitors
loads with excellent line and load regulation characteristics.
100 mΩ N-channel MOSFET
High efficiency (>90%) is obtained through the use of a low
ON-resistance N-channel MOSFET. The series consists of a Output voltage options: fixed 5V output and an adjustable version. -ADJ (outputs as low as 1.285V) -5.0 (output fixed to 5V)
The SIMPLE SWITCHER® concept provides for an easy to
use complete design using a minimum number of external ±1.5% feedback reference accuracy
components and National’s WEBENCH® design tool. Switching frequency of 500k Hz National’s WEBENCH® tool includes features such as exter-
-40°C to 125°C operating junction temperature range
nal component calculation, electrical simulation, thermal sim-
Adjustable soft-start
ulation, and Build-It boards for easy design-in. The switching
Adjustable current limit
clock frequency is provided by an internal fixed frequency os-
cillator which operates at 500 k Hz. The LM22679 series also Integrated boot diode
has built in thermal shutdown and current limiting. The current Fully WEBENCH® enabled limit threshold can be adjusted using an external resistor. An
Step-down and inverting buck-boost applications
adjustable soft-start feature is provided by selecting an ap- propriate external soft-start capacitor.
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
© 2008 National Semiconductor Corporation www.national.com
Page Summary Contents For National Semiconductor LM22679 Data Handbook
Manual Details
| Brand | National |
|---|---|
| Pages | 14 |
| File Size | 350.69 KB |
| Published | June 17, 2026 |
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Frequently Asked Questions
What is the required input voltage range for this regulator?
The LM22679 operates with a wide input voltage range of 4.5V to 42V.
How do I adjust the current limit?
The current limit threshold can be adjusted using an external resistor connected between pin 5 (IADJ) and GND.
Does it offer a soft-start function?
The operating junction temperature range is specified as -40°C to +125°C.