Step-down switching regulator , adj., 8 ... 40 Vin, 1.2 ... 37 V

LM2678 SIMPLE SWITCHER® High Efficiency 5-A Step-Down Voltage Regulator

Description:
The LM2678 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 complete design using a minimum number of external components. A high fixed frequency oscillator (260 kHz) allows the use of physically smaller sized components. A family of standard inductors for use with the LM2678 are available from several manufacturers to greatly simplify the design process. The LM2678 series also has built-in thermal shutdown, current limiting, and an ON/OFF control input that can power down the regulator to a low 50µA quiescent current standby condition. The output voltage is ensured to a ±2% tolerance. The clock frequency is controlled to within a ±11% tolerance.

Features:
- Efficiency Up to 92%
- Simple and Easy to Design Using Off-the-Shelf External Components
- 120-mO 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
- 260-kHz Fixed Frequency Internal Oscillator
- -40 to 125°C Operating Junction Temperature Range
- Create a Custom Design Using the LM2678 With the WEBENCH® Power Designer

Applications
- Simple-to-Design, High Efficiency (>90%) Step-Down Switching Regulators
- Efficient System Preregulator for Linear Voltage Regulators
- Battery Chargers