The LT1738 is a switching regulator controller designed to lower conducted and radiated electromagnetic interference (EMI). Ultralow noise and EMI are achieved by controlling the voltage and current slew rates of an external N-channel MOSFET switch. Current and voltage slew rates can be independently set to optimize harmonic content of the switching waveforms vs efficiency. The LT1738 can reduce high frequency harmonic power by as much as 40dB with only minor losses in efficiency.

The LT1738 utilizes a current mode architecture optimized for single switch topologies such as boost, flyback and Cuk. The IC includes gate drive and all necessary oscillator, control and protection circuitry. Unique error amp circuitry can regulate both positive and negative voltages. The internal oscillator may be synchronized to an external clock for more accurate placement of switching harmonics.

Protection features include gate drive lockout for low V_IN, soft-start, output current limit, short-circuit current limit-ing, gate drive overvoltage clamp and input supply undervoltage lockout.

Applications

• Power Supplies for Noise Sensitive Communication Equipment
• EMI Compliant Offline Power Supplies
• Precision Instrumentation Systems
• Isolated Supplies for Industrial Automation
• Medical Instruments
• Data Acquisition Systems