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 external component calculation, electrical simulation, thermal simulation, and Build-It boards for easy design-in. The switching clock frequency is provided by an internal fixed frequency oscillator 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.
The LM22678 series provides a monolithic step‑down switching regulator capable of delivering up to 5 A with high efficiency (>90%). It features a fixed 5 V output version and an adjustable version that can be set as low as 1.285 V. The device integrates a low‑ON‑resistance N‑channel MOSFET, internal voltage‑mode control, and a precision enable pin for easy power sequencing.
Designed for industrial control, telecom, embedded and automotive applications, the regulator includes current limiting, thermal shutdown, and remote shutdown protection. It is supplied in a TO‑263 THIN (exposed‑pad) package and is fully supported by National’s WEBENCH design tools for component selection and simulation.
| Input voltage range | 4.5 V to 42 V |
|---|---|
| Maximum output current | 5 A |
| Switching frequency | 500 kHz |
| Operating temperature range | -40 °C to 125 °C |
| Enable pin voltage range | -0.5 V to 6 V |
| Package | TO‑263 THIN (Exposed Pad) |
The regulator operates at a fixed switching frequency of 500 kHz.
It accepts an input voltage from 4.5 V up to 42 V.
Pull the EN (precision enable) pin low, below about 1.6 V, to shut down the regulator.
It includes current limiting, thermal shutdown, and remote shutdown capability.