POY5.JAN–McKenzie–SC
Impedance-controlled socket targets high-speed semiconductors
While the industry trend to faster clock speeds and rise times continues, semiconductor performance is ultimately limited by the relatively slow signal path through traditional IC sockets. But in 1993, McKenzie Technology's ZGA (impedance-controlled pin grid array) socket put an end to that limitation by providing an impedance matched signal path throughout the socket interface.
The socket uses a selective metallization process to create an interconnected ground plane around the contact housing. Using a plated-on-plastic technology, these ground planes encircle each signal pin and interconnect via plated-through-holes interstitched around each contact. The resultant signal path resembles a coaxial transmission line that reduces crosstalk and signal reflection problems.
The company can produce processor-specific sockets, which, taking into account a specific netlist, are producible with matched-impedance signal lines within the socket. This is achieved by varying the distance between the surrounding ground planes and signal contacts. The plated metallization pattern is custom designed by the company to match the user's impedance requirements, typically 50 ohms. When tested, one version of the socket exhibited an inductance of 2 nH, compared to 2.4 nH for a conventional PGA socket.
Crosstalk is 0.6% to 0.3% over a dc to 1-GHz range, compared to 10 GHz for a standard PGA socket. Characteristic impedance is 40 ohms, compared to 70 ohms for a standard PGA.
Currently, the socket is available in a 168-pin configuration for the Intel 66 MHz 80486 microprocessor, and a 273-pin configuration for the Pentium microprocessor. (Pentium socket, part No. ZGA 273H509B-2119-001, $12.21 ea/1,000–stock to 4 weeks ARO.)
McKenzie Technology
Fremont, CA
Debra Woods 510-651-2700
CAPTION:
The ZGA socket from McKenzie has a patented ground plane design that achieves a matched impedance signal path throughout the socket interface.
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