Original and new 100% LM2674M

1.LM2674M 2.SIMPLE SWITCHER Power Converter High Efficiency 500 mA Step-Down Voltage Regulator

General DescriptionThe LM2674 series of regulators are monolithic integrated circuits built with a LMDMOS process. These regulators provideall the active functions for a step-down (buck) switching regulator, capable of driving a 500 mA load current with excellentline and load regulation. These devices are available in fixed output voltages of 3.3V, 5.0V, 12V, and an adjustable output version.

Requiring a minimum number of external components, these regulators are simple to use and include patented internalfrequency compensation (Patent Nos. 5,382,918 and 5,514,947) and a fixed frequency oscillator.

The LM2674 series operates at a switching frequency of 260 kHz, thus allowing smaller sized filter components thanwhat would be needed with lower frequency switching regulators. Because of its very high efficiency (>90%), the coppertraces on the printed circuit board are the only heat sinking needed.

A family of standard inductors for use with the LM2674 are available from several different manufacturers. This featuregreatly simplifies the design of switch-mode power supplies using these advanced ICs. Also included in the datasheet areselector guides for diodes and capacitors designed to work in switch-mode power supplies.

Other features include a guaranteed ±1.5% tolerance on output voltage within specified input voltages and output loadconditions, and ±10% on the oscillator frequency. External shutdown is included, featuring typically 50 μA stand-by current.The output switch includes current limiting, as well as thermal shutdown for full protection under fault conditions.To simplify the LM2674 buck regulator design procedure, there exists computer design software, LM267X Made Simple(version 6.0).

Features* Efficiency up to 96%* Available in SO-8, 8-pin DIP and LLP packages* Computer Design Software LM267X Made Simple (version 6.0)* Simple and easy to design with* Requires only 5 external components* Uses readily available standard inductors* 3.3V, 5.0V, 12V, and adjustable output versions* Adjustable version output voltage range: 1.21V to 37V* ±1.5% max output voltage tolerance over line and load conditions* Guaranteed 500mA output load current* 0.25Ω DMOS Output Switch* Wide input voltage range: 8V to 40V* 260 kHz fixed frequency internal oscillator* TTL shutdown capability, low power standby mode* Thermal shutdown and current limit protection

Typical Applications* Simple High Efficiency (>90%) Step-Down (Buck) Regulator* Efficient Pre-Regulator for Linear Regulators* Positive-to-Negative Converter

Dimension (Unit: mm)

Original and new 100% LM2674M