Controlled Impedance Test Procedure for Rambus®

Rambus is a new high speed memory architecture for the PC that operates at 800MHz. This requires matched impedance on both the PC mother board and the memory boards - called RIMMs. The impedance of the Rambus system is 28 Ohms and the tolerance is 10%, which in practice is very tight. Rambus will not work unless the boards are made to meet this specification. You can learn more about Rambus at http://www.rambus.com.

Testing Rambus.

The Rambus controlled impedance PCBs can be tested using Polar's CITS500s Controlled Impedance Test System and a procedure for doing so is found in the following document.

CITS500s Procedure for Rambus Impedance Measurement (Microsoft Word 97) Polar Instruments Ltd Revised Jan 11, 2000 Compressed Zip file (260KB)

The Intel Corporation website has much information on Rambus and particularly an application note describing the methodology for testing Rambus using Time Domain Reflectometry (TDR).

	Printed Circuit Board (PCB) Test Methodology Intel Corporation
	Controlled Impedance Design and Test Intel Corporation Presentation

Polar recommends testing Rambus with the CITS500s Controlled Impedance Test System , software version 5.00 or above (32bit with 4-point calibration) and using the 28 Ohm IP probe. Existing Polar CITS100, CITS200, CITS500 and CITS500s customers can contact Martyn Gaudion at Polar for details of purchase and trade-in options.

Polar Instruments Ltd

Garenne Park, St Sampson, Guernsey, Channel Islands GY2 4AF, UK
http://www.polarinstruments.com

Tel: +44 (0) 1481 253081 Fax: +44 (0) 1481 252476 © Polar Instruments