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. This feature greatly simplifies the design of switch-mode power supplies using these advanced ICs. 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.
