Teledyne LeCroy QPHY-DDR4 - Manual (Page 45)

QPHY-DDR4 Software Option
In the Measure section:
• SRIN_dIVWR (P1) is measuring the slew rate of DQ on the rising edges. The slew rate is measured
across VdIVW_total centered at Vref. The minimum value is the measured value for
SRIN_dIVWR of DQ min. Since the limit in the specification is undefined this test is Informational
Only.
• tDQDQS (P2) is measuring the skew between DQ and DQS. Since this measurement is performed
once per burst, this shows how many W bursts were in the acquired waveform.
• t@SRINRmin (P4) displays the location of where the minimum value of SRIN_dIVWR occurred.
This is used to position the zoom traces at the location of the “worst case results”.
• P5: slew(Z3) displays the minimum value of SRIN_dIVWR and is used to display the slew rate
measurement markers.
Slew, Input Slew Rate (DQS and CK)
The input slew rate measurements on DQS and CK are still made following a traditional approach of Vref
to VIH(ac)/VIL(ac). These measurements are labeled as Slew_R and Slew_F in the report to higlight the
difference.
After the completion of the Slew_R test the oscilloscope is in the following configuration:
Figure 31 - Oscilloscope Configuration after Slew_R Test
Shown on this screen:
• Z2 is a zoom of F2, the acquired DQS signal after any probe deskew has been applied. The zoom is
positioned at the location of the “worst case” Slew_R measurement indicated by t@SRINRmin. A
trace label is applied on this trace according to the signal name assigned to DQS. This is the
signal which is measured in this test.
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