Teledyne LeCroy QPHY-LPDDR2 - Manual (Page 47)

QPHY-LPDDR2 Software Option
QPHY-LPDDR2-OM-G Rev B
47
tDSS, DQS Falling Edge to CK Setup Time
Time from DQS falling edge at VREF level to CK rising edge at VREF level, see Figure 26.
tDSH, DQS Falling Edge Hold Time from CK
Time from CK rising edge at VREF level to DQS falling edge at VREF level, see Figure 26.
tWPRE, Write Preamble
Time from when DQS begins to be driven (at the beginning of the preamble) to when it crosses Vref. This
is only measured on a write cycle.
tWPST, Write Postamble
Time from when DQS crosses Vref (at the beginning of the postamble) to when DQS stops being driven
(at the end of the postamble). This is only measured on a write cycle.
tDS(base), DQ and DM Input Setup Time
Input waveform timing tDS with differential data strobe enabled, is referenced from the input signal
crossing at the VIH(ac)min level to the differential data strobe crosspoint at VREF for a rising signal, and
from the input signal crossing at the VIL(ac)max level to the differential data strobe crosspoint at VREF for
a falling signal applied to the device under test. See “Figure 29. Command Input Setup and hold timing
[JESD209-2D figure 22]”.
DQS and DQS# signals must be monotonic between VIL(dc)max and VIH(dc)min.
Setup (tDS) nominal slew rate for a rising signal is defined as the slew rate between the last crossing of
VREF(dc) and the first crossing of VIH(ac)min. Setup (tDS) nominal slew rate for a falling signal is defined
as the slew rate between the last crossing of VREF(dc) and the first crossing of VIL(ac)max.
JESD209-2D Specific Note 8 (page 85 to 94) with tables 43 and 44 explain the limit compensation versus
the slewrate of the measured signals. Timing limits are initially specified for input slewrate of 1V/ns for
single-ended signals and 2V/ns for differential signal (for DQS and CK).
tDH(base), DQ and DM Input Hold Time
Input waveform timing tDH with differential data strobe enabled, is referenced from the differential data
strobe crosspoint at VREF to the input signal crossing at the VIH(dc)min level for a falling signal and from
the differential data strobe crosspoint at VREF to the input signal crossing at the VIL(dc)max level for a
rising signal applied to the device under test. See figure below.