PTB78560B

The PTB78560x is a series of 30–W rated isolated dc/dc converters, designed to operate from a standard 24–V or 48–V telecom central office (CO) supply. Housed in a 1×2 package, each model has a wide-adjust output voltage that can be set to one of the common intermediate bus voltages of 3.3 V, 5 V, or 12 V.

The PTB78560 series incorporates Auto-Track™, a feature that simplifies the power-up sequencing of multiple power modules that operate from the same intermediate bus. During a power-up cycle, modules with this feature have the capability of following a common ramp voltage applied to an input called Track. The PTB78560 series is specifically designed to control the Track voltage of any number of nonisolated downstream modules powered from its output. This ensures that the outputs of the downstream modules all rise simultaneously during power up. The PTB78560B (3.3 V) has an additional sequenced output, V_O Seq, which also rises with the Track voltage. This allows the V_O Seq output to power up simultaneously with the outputs from other power modules under the control of Auto-Track.

Whether used to facilitate power-up sequencing, or operated as a stand-alone module, the PTB78560 series includes many other features expected of high-performance dc/dc converter modules. Precise output voltage regulation is ensured with a differential remote sense. Operational features include an input undervoltage lockout (UVLO) and a dual-logic output enable control. Overcurrent and overtemperature protection ensure survival against load faults.

Typical applications include distributed power architectures in both telecom and computing environments, particularly complex digital systems requiring power sequencing of multiple power supply rails.