Dual ideal diode and hot swap controllers offer power and space savings
The ideal diodes replace two high power Schottky diodes and associated heat sinks, saving space while providing a low loss path to the load. The downstream Hot Swap control MOSFET protects the board and backplane from damage during live insertion and removal, and protects from short-circuit faults with a fast acting current limit and circuit breaker. Prioritization of the two supplies is made possible by a dedicated D2ON# pin, which turns off the ideal diode for a lower priority supply. In addition to redundant power supply ORing, the LTC4227 makes an excellent diode replacement in supply holdup applications where momentary collapse of supply voltage is isolated from the load.
Linear Technology is also introducing the LTC4225, which provides two independent ideal diode and Hot Swap paths for two power rails. While offering many similar features to the LTC4227, the LTC4225 can be configured as a power prioritizer and is also suited to MicroTCA systems, where the outputs of 12 V power modules are used to power multiple advanced mezzanine cards.
Availability and Pricing
The LTC4227 and LTC4225 are offered in two versions: the LTC422x-1 latches off after a fault, whereas the LTC422x-2 provides automatic retry after a fault. Commercial and industrial grades offer unique operating temperature ranges from 0 to 70°C and -40 to 85°C, respectively. The LTC4227 is available in 20-lead 4 mm x 5 mm QFN or 16-lead SSOP packages, while the LTC4225 is offered in 24-lead 4 mm x 5 mm QFN or SSOP packages. Pricing starts at $3.41 each in 1,000 piece quantities.