The LM2679S-ADJ 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 ON-resistance 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 LM2679S-ADJ are available from several manufacturers to greatly simplify the design process.
Other features include the ability to reduce the input surge current at power on by adding a soft-start timing capacitor to gradually turn on the regulator. The LM2679S-ADJ series also has built-in thermal shutdown and resistor programmable current limit of the power MOSFET switch to protect the device and load circuitry under fault conditions. The output voltage is specified to a ±2% tolerance. The clock frequency is controlled to within a ±11% tolerance.
Feature
- Efficiency Up to 92%
- Simple and Easy to Design Using Off-The-Shelf
External Components - Resistor Programmable Peak Current Limit Over a
Range of 3 A to 7 A - 120-mΩ DMOS Output Switch
- 3.3-V, 5-V, 12-V Fixed Output and Adjustable
(1.2 V to 37 V) Versions - ±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
- Soft-Start Capability
- –40 to 125°C Operating Junction Temperature
Range
