LM22670 3A SIMPLE SWITCHER®, Step-Down Voltage Regulator with Synchronization or Adjustable Switching Frequency
October...
LM22670 3A SIMPLE SWITCHER®, Step-Down Voltage
Regulator with Synchronization or Adjustable Switching Frequency
October 17, 2008
LM22670 3A SIMPLE SWITCHER®, Step-Down Voltage
Regulator www.datasheet4u.com with Synchronization or Adjustable Switching Frequency
General Description
The LM22670 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 3A 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 1MHz. It is also possible to selfsynchronize multiple
regulators to share the same switching frequency. The LM22670 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 curr...