Provides load current monitoring output

Linear Technology Corporation announces the introduction of the LTC4236, a dual diode-OR and single hot-swap controller with load current monitoring output. High-availability systems such as servers, network routers, and solid-state drives (SSDs) use a variety of power supplies to power circuit boards.

The LTC4236 integrates the diode-OR function of two power supplies while providing inrush current control, overcurrent protection, and current monitoring in a compact footprint. For supply ORing, low-loss N-channel MOSFETs replace power Schottky diodes and associated heat sinks, reducing voltage drop, power loss, and solution area.


Photo Caption: Dual power ORing & single hot swap controller

Downstream Hot Swap MOSFETs provide safe board insertion and removal from a live backplane, and a fast-acting current-limiting circuit breaker provides short-circuit protection. A low-offset ground-referenced output signal enables load current measurement using an external analog-to-digital converter (ADC).

The LTC4236 regulates a low 15mV forward voltage drop across the diode MOSFETs to protect against DC reverse current while ensuring smooth current transfer during power supply switchover. The fast turn-on and turn-off capabilities of an ideal diode minimize output voltage droop and transient reverse current.

The diode off input and back-to-back MOSFET capability allow for power priority when ORing the primary power supply with a high voltage auxiliary supply or battery. In an output short-circuit, the LTC4236 reduces the current limit to a low 25mV and operates an adjustable timer to limit MOSFET power dissipation. For application flexibility, the connector debounce filter delay is fixed internally or adjustable with an external capacitor.

The LTC4236 is available in two options. The LTC4236-1 turns off after an overcurrent fault, while the LTC4236-2 automatically turns on with a 0.15% duty cycle. Specified over the 0oC to 70oC commercial and −40oC to 85oC industrial temperature ranges, the LTC4236 is offered in a 28-pin 4mm x 5mm QFN package. Pricing starts at $4.25 each in 1,000-piece quantities.