[FAQ] What Multiplexers can I use for Hot-Swapping and Hot-Insertion Applications?

When looking for a multiplexer to be implemented for hot-insertion (also known as hot-swapping) applications. It is important to make sure it has Ioff Circuitry and the Partial Power Down Mode feature. We also recommend to pick a multiplexer with a continuous current rating of at least 100mA, so it can handle an in-rush current event during a hot insertion.

Ioff

The Ioff feature ensures that no excessive current is drawn from or to an input, output, or combined I/O that is biased to a specified voltage while the device is powered down.

Partial-Power-Down Mode

Partial-Power-Down Mode allows the I/O switch paths to go into high impedance mode. This only occurs when the device is not powered, meaning Vcc = 0V.

Electrical Protection Definitions

When it comes to Hot-Swapping and Hot-Insertion there are four categories of isolation that we need to understand.

Level 0 Isolation

A device with level 0 isolation is incapable of being inserted safely into a backplane without first powering down the host power supply

Level 1 Isolation

A device with level 1 isolation prevents damage to itself by limiting the current transfer between an energized bus and the device input and output when powered down (Vcc = 0V).

Level 2 Isolation – also known as Hot-Insertion

A device that supports hot insertion (level 2 isolation) prevents driver conflict during device insertion or removal. In addition to the level 1 isolation capabilities, the device remains in the high-impedance state from a power-supply voltage of 0V to a specified voltage.

Level 3 Isolation – also known as Live-Insertion

A device suitable for live insertion allows insertion or removal of a device without limitations, restrictions, or requirements of other circuitry on system power and signaling.

Multiplexers in Hot-Insertion

Our multiplexers are capable up to level 2 of isolation, meaning they can be used for hot insertion and hot swapping applications. Specifically, our CBT, CB3T, and CB3Q bus switches families.

Hot-Insertion Hero Devices