LM2676 SIMPLE SWITCHER® High Efficiency 3A Step-Down Voltage Regulator

FEATURES

• Efficiency Up to 94%

• Simple and Easy to Design with (Using Off- The-Shelf External Components)

• 150 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

APPLICATIONS

• Simple to Design, High Efficiency (>90%) Step-Down Switching Regulators

• Efficient System Pre-Regulator for Linear Voltage Regulators

• Battery Chargers

DESCRIPTION

The LM2676 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 3A 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 LM2676 are available from several manufacturers to greatly simplify the design process.

The LM2676 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.

Typical Application

Connection Diagrams

Absolute Maximum Ratings⁽¹⁾⁽²⁾

(1) Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings indicate conditions under which of the device is ensured. Operating Ratings do not imply ensured performance limits. For ensured performance limits and associated test condition, see the Electrical Characteristics tables.

(2) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/Distributors for availability and specifications.

(3) The absolute maximum specification of the 'Switch Voltage to Ground' applies to DC voltage. An extended negative voltage limit of -8V applies to a pulse of up to 20 ns, -6V of 60 ns and -3V of up to 100 ns.

(4) ESD was applied using the human-body model, a 100pF capacitor discharged through a 1.5 kΩ resistor into each pin.