DC/DC Controller Needs No EMI Filters

Designed to minimize conducted and radiated electromagnetic interference in step-up or step-down power supplies, the LT1683 push-pull dc/dc controller independently controls the output switch voltage and current slew rates. Low-switching harmonics are said to eliminate filters, EMI shields, and the need for iterating the PCB layout while driving external N-channel MOSFETs to deliver 10W or more of output power. The controller is said to reduce high frequency harmonic power by as much as 40 dB and error amp circuitry can regulate both positive and negative voltages for easier layout than conventional switching regulators. The internal oscillator frequency adjusts from 20 kHz to 250 kHz with a capacitor and a resistor. Pricing starts at $3.85 each/1,000. LINEAR TECHNOLOGY CORPORATION, Milpitas, CA. (408) 432-1900.