The LM22671 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 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 switching frequency can also be adjusted with an external resistor or synchronized to an external clock up to 1 MHz. It is also possible to self- synchronize multiple regulators to share the same switching frequency. The LM22671 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. An adjustable soft-start feature is provided by selecting an appropriate external soft-start capacitor.
The LM22671 series provides a monolithic step‑down (buck) switching regulator capable of delivering up to 500 mA with a wide input voltage range of 4.5 V to 42 V. It features an internally compensated voltage‑mode control loop, a low‑ON‑resistance N‑channel MOSFET, and a fixed 500 kHz switching frequency that can be adjusted between 200 kHz and 1 MHz or synchronized to an external clock.
The device includes protection functions such as current limiting, thermal shutdown, and a precision enable pin. It is offered in an 8‑lead PSOP‑8 package with an exposed pad for improved thermal dissipation, and is suitable for industrial control, telecom, automotive telematics, and other embedded applications.
| Input voltage range | 4.5 V to 42 V |
|---|---|
| Output current | 500 mA |
| Efficiency | up to 90 % |
| Package type | PSOP‑8 (Exposed Pad) |
| Enable pin threshold voltage | 1.3 V to 1.9 V |
| Thermal shutdown temperature | 150 °C |
| Operating temperature range | -40 °C to +125 °C |
The LM22671 operates from 4.5 V up to 42 V input.
It includes current limiting, thermal shutdown, and a precision enable pin for remote shutdown.