The data sheet introduces the features and characteristics of LTC1876 high performance triple output switching regulator and step-up regulator. The chip uses dual phase, dual synchronous step-down switching controller, drives all N-channel synchronous power MOSFET stages, and an internal 1A, 36V step-up regulator provides the third output. The chip uses OPTI-LOOP compensation, which optimizes the transient response over a wide range of output capacitance and ESR values. Each controller's RUN/SS pin provides both soft-start and an optional timed, short-circuit shutdown function that can be configured to latch off one or both controllers. Current foldback provides additional short-circuit protection. In an overvoltage condition, the bottom MOSFET is latched on until VOUT returns to normal. The FCB pin can be used to inhibit Burst Mode operation or to enable regulation of a secondary output voltage. The step-up regulator operates at 1.2MHz, allowing the use of tiny low cost capacitors and inductors. In addition, its internal 1A switch allows high current outputs to be generated. Its current mode control scheme provides excellent line and load regulation.
The LTC1876 is a high‑performance triple‑output switching regulator that combines two out‑of‑phase step‑down controllers with a high‑frequency step‑up regulator. It provides 5 V, 3.3 V standby, and a programmable high‑voltage output up to 34 V, making it suitable for notebook, PDA, and battery‑operated digital devices.
Key features include a wide 3.5 V‑36 V input range, programmable fixed frequency of 150 kHz‑300 kHz (up to 1.2 MHz for the step‑up stage), 99 % maximum duty cycle, and integrated protection such as short‑circuit shutdown and over‑voltage sensing. The device is supplied in a 36‑lead plastic SSOP package and operates from –40 °C to 85 °C.
| Input Voltage Range | 3.5 V to 36 V |
|---|---|
| Switching Frequency | 150 kHz to 300 kHz (step‑up up to 1.2 MHz) |
| Maximum Duty Cycle | 99 % |
| High Output Voltage | Up to 34 V |
| Standby Regulators | 5 V and 3.3 V |
| Package Type | 36‑Lead Plastic SSOP |
The device operates from 3.5 V up to 36 V input.
It provides a programmable fixed frequency of 150 kHz to 300 kHz, and the step‑up regulator can run at up to 1.2 MHz.
The controller can achieve a maximum duty cycle of 99 %.
It is supplied in a 36‑lead plastic SSOP package.