The LT ®1683 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 external N-channel MOSFET switches. Current and voltage slew rates can be independently set to optimize harmonic content of the switching waveforms vs efficiency. The LT1683 can reduce high frequency harmonic power by as much as 40dB with only minor losses in efficiency. The LT1683 utilizes a dual output (push-pull) current mode architecture optimized for low noise topologies. The IC includes gate drivers and all necessary oscillator, control and protection circuitry. Unique error amp cir- cuitry can regulate both positive and negative voltages. The oscillator may be synchronized to an external clock for more accurate placement of switching harmonics. Protection features include gate drive lockout for low VIN, opposite gate lockout, soft-start, output current limit, short-circuit current limiting, gate drive overvoltage clamp and input supply undervoltage lockout.
The LT1683 is a slew‑rate‑controlled, ultralow‑noise push‑pull DC/DC controller designed for low‑EMI power supplies and precision instrumentation. It integrates dual N‑channel MOSFET drivers, an internal oscillator, and extensive protection features such as soft‑start, over‑voltage shutdown, and gate‑drive lockout.
The document details absolute maximum ratings, electrical characteristics, pin descriptions, typical performance graphs, and example application schematics. It also includes ordering information for the 20‑lead SSOP package and notes on lead‑free options.
| Maximum Switch Frequency | 250 kHz |
|---|---|
| SYNC Pin Input Threshold | 0.7 V to 2.0 V |
The controller’s oscillator can operate up to 250 kHz.
The SYNC pin accepts an input threshold between approximately 0.7 V and 2.0 V.