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
Soft-start and frequency synchronization
Thermal shutdown and current limit protection
Description The LM2671 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 500mA load current with excellent line
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 internal frequency
compensation (Patent Nos. 5,382,918 and 5,514,947), fixed frequency oscillator, external shutdown, soft-start, and frequency
synchronization.
The LM2671 series operates at a switching frequency of
260 kHz, thus allowing smaller sized filter components than what would be needed with lower frequency switching regulators. Because
of its very high efficiency (>90%), the copper traces on the printed circuit board are the only heat sinking needed.
A family of standard inductors for use with the LM2671 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 datasheet are selector
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 load conditions,
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 LM2671 buck regulator design procedure, there exists computer design software,
LM267X Made Simple
(version 6.0).
Applications
Simple High Efficiency (>90%) Step-Down (Buck) Regulator
Efficient Pre-Regulator for Linear Regulators
See Layout Guidelines
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Also Recommended
| LM22671▲ | Wider Input Voltage Range (4.5 To 42V), 500 KHz Or Adjustable Switching Frequency Up To 1MHz |
| LM25574▲ | Fast Transient Response And Higher Switching Frequency (Up To 1MHz) |
| LM5574▲ | Wider Input Voltage Range (6 To 75V) And Higher Switching Frequency (Up To 500kHz) |
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LM22671
