[SI-LIST] LPDDR2 IO query

From: rahul kumar <rahul05kumar@xxxxxxxxx>
To: si-list@xxxxxxxxxxxxx
Date: Thu, 2 Apr 2009 11:29:12 +0530

Hello all,
  I have a query about  LPDDR2 IO driver ( 800  ) specifications. In the
specifications output driver DC impedance is specified as +/-15% with
calibration and +/-30% without calibration. However slewrate specifications
are specified with +/-30% impedance variations. Also impedance steps are
provided of 34.3 , 40, 48, 60, 80 ohms. Now my question is ;
1.   What is the purspose calibrated impedances ? Without calibration slew
rate can well be met ( Specified with +/- 30 %) . Is overshoot and
undershoot specifcations are difficult to acheieve without calibration.
2.   For LPDDR controller IO transmitter/receiver ,  how timing
specifications (Skew and jitter) are calculated ? Any document / link about
how these calculations are done for controller IO.

Thanks in advance ,

Best regards.
Rahul.


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[SI-LIST] LPDDR2 IO query

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