LM22671 Datasheet | National Semiconductor

Features October 17, 2008 LM22671 500 m A SIMPLE SWITCHER®, Step-Down Voltage .. Regulator with Features General Description The LM22671 series of regulators are monolithic integrated circuits which provide all of the active functions for a stepdown (buck) switching regulator capable of driving up to 500 m A 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 plete design using a minimum number of external ponents and National’s WEBENCH® design tool. National’s WEBENCH® tool includes features such as external ponent 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 k Hz. 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 selfsynchronize 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. Features - - - - - - - - - - - - - Wide input voltage range: 4.5V to 42V Internally pensated 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 k Hz, adjustable between 200 k Hz and 1 MHz -40°C to 125°C operating junction temperature range Precision enable pin Integrated boot diode Adjustable soft-start Fully WEBENCH® enabled Step-down and inverting...