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 5A 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 3.3V, 5V and 12V 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 (260KHz) 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.
Efficiency Up to 92%
Simple and Easy to Design with (Using Off-The-Shelf External Components)
120 mΩ DMOS Output Switch
3.3V, 5V and 12V Fixed Output and Adjustable (1.2V to 37V ) Versions
50μA Standby Current When Switched OFF
±2% Maximum Output Tolerance Over Full Line and Load Conditions
Wide Input Voltage Range: 8V to 40V
260 KHz Fixed Frequency Internal Oscillator
−40 to +125°C Operating Junction Temperature Range