Teledyne LeCroy QPHY-DDR4 - Manual (Page 53)

QPHY-DDR4 Software Option
In the Measure section:
• SRQ R (P1) is measuring the slew rate of DQ on the rising edges. The slew rate on the rising edge
is measured from VOL(ac) to VOH(ac). The minimum value is the measured value for SRQ R of
DQ min. This test is considered passing if the measured value is greater than 4 GV/s.
• tDQDQS (P2) is measuring the skew between DQ and DQS. Since this measurement is performed
once per burst, this shows how many R bursts were in the acquired waveform.
• t@SRQ Rmin (P4) displays the location of where the minimum value of SRQ R 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 SRQ R and is used to display the slew rate
measurement markers.
Timing Tests (CKdiff-DQSdiff-DQse)
The timing tests will be discussed in 12 groups in this section. The groups of tests that are run are:
Timing Tests on R bursts
1. tDQSQ_total, DQS to DQ Skew
2. tQSH/tQSL, DQS Output High/Low Time
3. tQH_total, DQ Output Hold Time
4. tDQSCK, CK to DQS Skew
5. tHZ/tLZ, High/Low Impedance Time
6. tRPRE/tRPST, Read Pre/Postamble Time
Timing Tests on W bursts
7. tDQSS, CK to DQS Skew
8. tDQSH/tDQSL, DQS Input High/Low Pulse Width
9. tDIPW, DQ Input Pulse Width
10. tDSS/tDSH, DQS to CK Setup/Hold Time
11. Tdqs/Tdqh, DQ to DQS Setup/Hold Time
12. tWPRE/tWPST, Write Pre/Postamble Time
Each of these tests are described in detail below.
tDQSQ_total, DQS to DQ Skew
The purpose of this test is to characterize the latest valid transition of DQ. This test measure the
maximum skew between DQS at Vref and DQ at Vref for all DQ transitions during a R burst.
After the completion of the tDQSQ_total test the oscilloscope is in the following configuration:
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