Active circuitry in Eurocard connector saves board space
Custom module inserted into connector also improves performance Before
1992, Eurocard connectors served only to passively interface electrical
circuitry to the backplane. But the Active Eurocard Connector from AMP
demonstrates that the connector can serve an active function as well. This
connector incorporates active electronic circuitry in an interchangeable
module. This architecture both saves space on the pc board and improves
electrical performance. The Active Eurocard Connector is right-angled to
connect daughterboards to the backplane. The connector mates with standard
DIN type C backplane connectors used in VMEbus and Multibus applications.
Further, the active device module is customized to user requirements by
either AMP or the user. While the typical connector module contains the IC
drivers and receivers normally mounted on the pc board, the module can
also incorporate passive components like resistors. Two elastomeric
strips attach the module to the connector's housing, which itself has a
three-dimensional circuit pattern. The module is held in place with a
retaining bracket. Modules can be easily modified to meet different
requirements. AMP estimates that 3 to 5 in.2 of board space are
typically freed for other functions because the active circuitry resides
within the connector. Nonactive circuitry can continue to reside on the pc
board without sacrificing performance. The shorter signal path between the
daughtercard and backplane minimizes bulk bus-loading effects. Total
packaging bus-loading effects for a connector in a typical VMEbus
application include 13 pF of capacitance and 45 nH of inductance.
By contrast, the Active Eurocard Connector exhibits 6 pF of capacitance and
21 nH of inductance in the same application. Impedance deviation between
the Active Eurocard Connector's three rows is also better–53 to 55 ohms
at a 1-ns edge rate against a 50-ohm test bed, compared to 60 to 68 ohms
for a standard connector. The connector has 96 contacts on a 0.100-in.
grid, with 126 solder-tail pins on a 0.100 x 0.075-in. grid interfacing
the daughterboard. The active module measures 3.28 x 0.800 in. The
connector's housing is liquid-crystal polymer, and contacts are
gold-plated phosphor bronze. ($14 to $15 ea/prod qty without active device
module–prototypes from stock.)
AMP Inc., Harrisburg, PA
Product information Center 800-522-6752
CAPTION:
The Active Eurocard Connector contains active circuitry, such as drivers
and receivers, within its housing. The connector improves overall system
performance and frees up valuable pc-board space.
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