LM2675N-ADJ/NOPB

The LM2675 series of regulators are monolithic integrated DC-DC converter circuits built with a LMDMOS process. These regulators provide all the active functions for a step-down (buck) switching regulator, capable of driving a 1-A 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 LM2675 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 LM2675 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 ±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) Regulator
• Efficient Preregulator for Linear Regulators
• Positive-to-Negative Converter

Key features

• Efficiency up to 96%
• Available in 8-Pin SOIC, PDIP, and 16-Pin WSON Package
• Requires only 5 External Components
• 3.3-V, 5-V, 12-V, and Adjustable Output Versions
• Adjustable Version Output Voltage Range: 1.21 V to 37 V
• ±1.5% Maximum Output Voltage Tolerance Over Line and Load Conditions
• Ensured 1-A Output Load Current
• Wide Input Voltage Range: 8 V to 40 V
• 260-kHz Fixed Frequency Internal Oscillator
• TTL Shutdown Capability, Low-Power Standby Mode
• Thermal Shutdown and Current Limit Protection