This document introduces LT1680, a high-power, current-mode switching power supply controller optimized for boost topologies. The IC drives an N-channel MOSFET switch for DC/DC converter applications up to 60V input. A high current gate drive output handles up to 10,000pF gate capacitance, enabling the construction of high power DC/DC convert- ers. Current sense common mode range up to 60V allows current sensing to be referenced to the input supply, eliminating the need for sense blanking circuits. The LT1680 incorporates programmable average current limiting allowing accurate limiting of DC current in the magnetics, independent of ripple current . User adjustable slope compensation provides stable operation at duty cycles up to 90%. The LT1680 operating frequency is programmable and can be synchronized up to 200kHz. Minimum off-time operation provides switch protection. The IC also incorpo- rates a soft start feature that is gated by both shutdown and undervoltage lockout conditions.
This datasheet describes the LT1680 high‑power step‑up DC/DC controller, including its features such as programmable average current limiting, undervoltage lockout, and synchronizable oscillator up to 200 kHz. It lists absolute maximum ratings, electrical characteristics, and typical performance curves for supply current, duty cycle, and temperature.
The document also details the pin functions, package options (16‑lead PDIP and SOIC), and a typical application circuit. Reference design information, such as soft‑start behavior and 5 V reference output capability, is provided for designers integrating the LT1680 into boost converter designs.
| Power Supply Voltage Range | -0.3 V to 20 V |
|---|---|
| Operating Frequency (Free Run) | 200 kHz |
| Maximum Duty Cycle | up to 90 % |
| 5 V Reference Output Current | 65 mA |
| Undervoltage Lockout Threshold (Rising) | 9.35 V to 9.95 V |
The LT1680 can operate up to 200 kHz in free‑run mode.
The 5 V reference output can source up to 65 mA.
The RUN/SHDN pin threshold is typically 1.25 V.
The device tolerates a supply voltage from –0.3 V up to 20 V.