at DesignCon Santa Clara,
CA - February 2004
Dr. Edward P. Sayre, P.E.
Dr. Edward P. Sayre, III
Mr. Michael Baxter
Mr. Scott Mickievicz, ITT Cannon Industries
Tempus-6000 is a Surface Mount Technology (SMT)
connector with significant differences in improved signal integrity and
mechanical performance over connectors that require through vias for
mounting and connections. Like its predecessor, the thru-pin Tempus-4000,
the T-6000 is a differential mode only connector and is available in both
5-row and 8-row versions with improved daughter card C & F row
grounding and impedance control. Thinner pins result in Smaller parasitics
for the headerside pins and the continuation of the dedicated grounded C
& F row pins have larger aspect ratios (flat and wider) than standard
pins for improved return impedance and lower inductance. The shield and
ground return pins use a direct ground connect buried via technology in
which the patented connector pin stubs are soldered directly into the
buried vias for improved mounting strength and low parasitics.
NESA has utilized a unique SPICE extraction process to characterize the
T-6000 connector as well as its close relative, the thru-pin Tempus-4000.
This process emphasizes both time and frequency domain electromagnetic
analyses as the first step in a more complete SPICE extraction of the
internals of the T-4000 and T-6000 shielded connectors and mounting
footprint parasitics. The process is unique in that those portions of the
connector appropriately described as a “distributed system” will be
represented in terms of a frequency dependent Transmission matrix (T—Parameters)
while those portions appropriately described as “parasitics” will be
described in terms of unique coupled circuit elements or equivalent
T-Parameters, resulting in a comprehensive description of the differential
connector paths with mounting or footprint parasitics.
A set of test boards were designed which specifically address the issues
of footprint extraction, use of calibration lines for transmission and
impedance de-imbedding and the “trimming” of the electromagnetic extracted
parameters to fit the experimental data. The work makes use of NESA’s
“Passive Signal Integrity™” virtual signal integrity laboratory including
its recent extensions to include both the time and the frequency domains.
This paper describes how this methodology was followed and the results
of the extraction analysis of the unique T-6000 and T-4000 connectors. The
process provides the connector designer as well as its adopters with the
means to independently vary the footprint parasitics depending on the
mounting footprint trace approach (broadside or edge coupled), trace
routing density and PCB material selection.
Results show that the elimination of the thru-via stubs in both the
signal traces and ground return structure by the use of SMT mounting
improves the overall bandwidth of Tempus-6000 enabled backplane
differential channels and provides a clear approach to 10 Gbps operation
->This paper is available from NESA for $15.00 to
cover management costs. We accept credit
card payment for purchase of the papers. The requested paper will be
emailed to you shortly after your order is received.