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Regarding Agilent probes (Agilent E 5404A soft touch )

Question asked by g_man_008 on Aug 21, 2008
Latest reply on Aug 21, 2008 by g_man_008
We are currently working on a logic analyzer probe card for one of our DDR memory cards. This card should enable at speed (200MHz) probing of the memory interface signals without significantly deprecating the signal quality at DDR memory pins. For this we need to do accurate pre-layout and post-layout Signal Integrity Analysis of the whole scheme. There a few doubts and we need a few clarifications in this regard:

We are planning to use Agilent 5404A soft touch connector less probe for inline probing of the memory signals. The load model of the probe is present in the data sheet (RC model).  But we couldn’t locate the model of the cable (its long!)  which connects the probe head (in the retention module) to the analyzer port. Can we get the exact model of the cable (impedance and propagation delay) as well as the load at the LA port (at the end of the cable) - transmission line LRC model to be specific.


Does the soft touch connector less probe (the end which connects to the proposed card) have any active/ isolation/cancellation circuitry/buffer? If not how is the signal quality maintained in presence of significant reflections from the long cable.


We also envision use of alternate scheme- that is using standard 20 pin headers which can be used with normal LA probes.  Is there any RC model for the normal 20 pin probes and cable from Agilent(not the soft touch one)?  

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