LM2677 Datasheet | Texas Instruments

Features - 1 Efficiency up to 92% - Simple and Easy to Design Using Off-the-Shelf External ponents - 100-mΩ DMOS Output Switch - 3.3-V, 5-V, and 12-V Fixed Output and Adjustable (1.2 V to 37 V) Versions - 50-μA Standby Current When Switched OFF - ±2% Maximum Output Tolerance Over Full Line and Load Conditions - Wide Input Voltage Range: 8 V to 40 V - External Sync Clock Capability (280 k Hz to 400 k Hz) - 260-k Hz Fixed Frequency Internal Oscillator - - 40°C to 125°C Operating Junction Temperature Range 2 Applications - Simple to Design, High Efficiency (> 90%) Step Down Switching Regulators - Efficient System Preregulator for Linear Voltage Regulators - Battery Chargers - munications and Radio Equipment Regulator With Synchronized Clock Frequency 3 Description The LM2677 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 5-A loads with excellent line and load regulation characteristics. High efficiency (>90%) is obtained through the use of a low onresistance DMOS power switch. The series consists of fixed output voltages of 3.3-V, 5-V, and 12-V and an adjustable output version. The SIMPLE SWITCHER® concept provides for a plete design using a minimum number of external ponents. The switching clock frequency can be provided by an internal fixed frequency oscillator (260 k Hz) or from an externally provided clock in the range of 280 k Hz to 400 k Hz, which allows the use of physically smaller-sized ponents. A family of standard inductors for use with the LM2677 are available from several manufacturers to greatly simplify the design process. The external Sync clock provides direct and precise control of the output ripple frequency for consistent filtering or frequency spectrum positioning. The LM2677 series also has built-in thermal shutdown, current-limiting, and an ON/OFF control input that can power down the regulator to a low 50-μA quiescent-current standby...