Dual-supply controller enables hot swapping

Edited by the Electronicstalk editorial team Jan 9, 2008

Dual supply hot swap controller enables live insertion and removal of mezzanine cards on AdvancedTCA carrier blades, MicroTCA systems or proprietary network platforms.

New from Linear Technology, the LTC4223 is a 12/3.3V dual supply hot swap controller that enables live insertion and removal of mezzanine cards used on AdvancedTCA carrier blades, MicroTCA systems or proprietary network platforms.

The PCI Industrial Computer Manufacturers Group (PICMG) has developed the Advanced Mezzanine Card (AMC) standard that defines the requirements for addon modules to expand the functionality of an AdvancedTCA carrier board, an open-industry standard intended to address the rapidly changing needs of communications network infrastructure.

These modules are also suitable for MicroTCA applications, an emerging standard that provides a scaled version of ATCA for more compact and price-sensitive applications.

The LTC4223 is the first hot swap controller targeted specifically for AMC/MicroTCA applications that meets the full requirements outlined in the PICMG AMC standard.

The LTC4223 provides independently controlled turn-on and shutdown of the 12V main and 3.3V auxiliary supply rails used on the mezzanine card.

The main 12V rail is controlled via an external N-channel MOSFET, while the 3.3V rail uses an integrated 0.3ohm switch for auxiliary or management power up to 165mA.

For the 12V rail, key features include a fast acting current limit in the event of short circuit faults, with guaranteed 5% accuracy.

An external current sense resistor adjusts the current trip threshold.

The LTC4223 also provides a 12V current sense monitoring output that can be connected to a low cost ADC like the LTC2450.

Separate power good outputs are available with 3% accurate thresholds set 10% and 15% below the 12V and 3.3V rails, respectively.

A fault output alerts the host processor if an overcurrent fault has occurred on either supply, while a separate VCC pin decouples the IC supply from faults on the 3.3V rail.

The LTC4223 includes a gate-source clamp to protect the external MOSFET from hard shorts on the output.

Absolute maximum ratings of 20 and 10V for the respective supplies ensure ruggedness when confronted with short overvoltage spikes and ringing present in harsh Hot Swap environments.

The LTC4223 is offered in two versions: the LTC4223-1 latches off after a fault, the LTC4223-2 provides automatic retry after a fault.

Specified over the commercial and industrial temperature ranges, the LTC4223 is offered in 16-lead SSOP and 5 x 4mm DFN packages.

Available today, pricing begins at US $2.10 each in 1000-piece quantities.

Linear Technology offers a wide portfolio of products that support AdvancedTCA platforms.