Board power connectors that make connections in sequence for hot-swap applications introduced by Mill-Max

March 3, 2020
A common use for First Mate/Last Break (FMLB) connectors is to establish the ground path before making any other power or signal connections.

OYSTER BAY, N.Y. – Mill-Max Manufacturing Corp. Inc. in Oyster Bay, N.Y., is introducing single- and double-row First Mate/Last Break (FMLB) connectors for applications that must make and break electrical signals in sequence, rather than all at once, such as in hot swapping or hot plugging.

A common use for First Mate/Last Break (FMLB) connectors is to establish the ground path before making any other power or signal connections.

FMLB connectors do this by eliminating stray currents that otherwise might damage devices or components. Hot plugging or hot swapping that make no ground contact first may cause the circuit to generate equalizing currents that see a low-resistance path.

These currents may run between devices or components in a direction that can cause damage and failures. The same is true on disconnect with the ground path remaining in place until all other signal are de-energized.

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In other applications FMLB connectors may power indicator lights or send an alert signal before energizing the prime circuit of the unit.

FMLB consists of six new connectors, three unique configurations each available in single- and double-row versions, all on 0.1-inch pin centers.

The single-row versions have taller pins in the first and last positions, and the double-row versions have four taller pins, two on each end. There are four SMT and two through-hole connector options.

The 811/813 series low-profile SMT versions have an initial height of 0.217 inches for the tallest pins with a 0.020-inch offset to the remaining pins, while the 812/814 series provide an initial height of 0.288 inches, an offset of 0.033 inches and 0.09 inches maximum stroke on the longer end pins to allow for greater compression.

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The 825/827 series through-hole connectors have an initial height of 0.332-inches for the tallest pins, an offset of 0.030 inches, and each pin has a maximum stroke of 0.09 inches.

The connectors feature spring pins with precision-machined external components and high-reliability internal springs, all gold-plated to ensure high conductivity, corrosion resistance, and durability.

The pins have a current rating of 2 amps and the connector housings are molded from high-temperature thermoplastic, suitable for most soldering processes.

For more information contact Mill-Max online at

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