Teledyne LeCroy QPHY-DDR4 - Manual (Page 51)

QPHY-DDR4 Software Option
Figure 38 – Overshoot/Undershoot Results
In the Measure section:
• OvershootArea (P1) is measuring the overshoot peak amplitude above VDDQ for of each DQ
pulse. The VDDQ level is indicated the cursor. The peak amplitude is measured only 1 UI after a
transition. The maximum value is the measured value for DQ Overshoot area Max. This test is
considered passing if the measured value is less than 200 pVs.
• t@AreaMax (P3) displays the location of where the maximum value of OvershootArea occurred.
This is used to position the zoom traces at the location of the “worst case results”.
SRQ, Output Slew Rate
The purpose of this test is to characterize the slew rate on DQ and DQS of all of the R burst (output) in
the acquisition. This test is performed on both rising (SRQ) and falling edges (SRF) and both the
minimum and maximum values are measured.
Note: Only slew rate measured on the rising edge of DQ will be discussed below. The measurement
methodology is exactly same for the falling edge except the slew rate is measured from VOH(ac) to
VOL(ac) instead of VOH(ac) to VOL(ac). The measurement methodology is also identical for DQS.
924291 Rev A 51