LM2674MX-ADJ/NOPB

The LM2674 series of regulators are monolithic integrated circuits built with a LMDMOS process. These regulators provide all the active functions for a step-down (buck) switching regulator, capable of driving a 500-mA load current with excellent line and load regulation. These devices are available in fixed output voltages of 3.3 V, 5 V, 12 V, and an adjustable output version. Requiring a minimum number of external components, these regulators are simple to use and include patented internal frequency compensation and a fixed frequency oscillator. The LM2674 series operates at a switching frequency of 260 kHz, thus allowing smaller sized filter components than what is required with lower frequency switching regulators. Because of very high efficiency (>90%), the copper traces on the printed circuit board are the only heat sinking required. A family of standard inductors for use with the LM2674 are available from several different manufacturers. This feature greatly simplifies the design of switch-mode power supplies using these advanced ICs. Also included in the data sheet are selector guides for diodes and capacitors designed to work in switch-mode power supplies. Other features include an ensured ±1.5% tolerance on output voltage within specified input voltages and output load conditions, and ±10% on the oscillator frequency. External shutdown is included, featuring typically 50-μA standby current. The output switch includes current limiting, as well as thermal shutdown for full protection under fault conditions.

Applications

• Simple high efficiency (>90%) step-down (buck) regulators
• Efficient preregulator for linear regulators
• Positive-to-negative converters

Key features

• Efficiency up to 96%
• Available in 8-pin SOIC, PDIP, and 16-pin WSON packages
• Simple and easy to design with
• Requires only five external components
• Uses readily available standard inductors
• 3-V, 5-V, 12-V, and adjustable output versions
• 1.21-V to 37-V adjustable version output voltage range
• ±1.5% maximum output voltage tolerance over line and load conditions
• Ensured 500-mA output load current
• 0.25-Ω DMOS output switch
• 8-V to 40-V wide input voltage range
• 260-kHz fixed frequency internal oscillator
• TTL shutdown capability, low power standby mode
• Thermal shutdown and current limit protection
• Create a custom design using the LM2674 with the WEBENCH Power Designer