15
Data Strobe Timing (DST) Tests
252
DDR2(+LP) Compliance Testing Methods of Implementation
tDVAC (Strobe), Time above V
IHdiff(AC)
/ below V
ILdiff(AC)
- Test Method of Implementation
The purpose of this test is to verify that the time the strobe signal is above V
IHdiff(AC)
and below
V
ILdiff(AC)
is within the conformance limits as specified in the JEDEC specification.
Signals of Interest
Mode Supported: LPDDR2 only
Signal cycle of interest: Write
Signal(s) of Interest:
• Data Strobe Signal (supported by Data Signal)
Optional signal(s):
• Chip Select Signal (this signal is used to separate DQS signals from different rank of memory)
Signals required to perform the test on the oscilloscope:
• Data Signal, DQ
• Data Strobe Signal, DQS
• Chip Select Signal, CS (optional)
Test Definition Notes from the Specification
Test References
See Table 78 - Allowed Time Before Ringback (tDVAC) for CK_t-CK_s and DQS_t- DQS_c in the
JESD209-2B
.
PASS Condition
The worst measured tDVAC(Strobe) should be within the specification limit.
Table 171
Allowed time before ringback (tDVAC) for CK_t-CK_s and DQS_t-DQS_c
Slew Rate
tDVAC [ps]
@ | V
IH/Ldiff(AC)
| = 440 mV
tDVAC [ps]
@ | V
IH/Ldiff(AC)
| = 600 mV
Min
Min
> 4.0
175
75
4.0
170
57
3.0
167
50
2.0
163
38
1.8
162
34
1.6
161
29
1.4
159
22
1.2
155
13
1.0
150
0
< 1.0
150
0
Summary of Contents for D9020DDRC
Page 1: ...Keysight D9020DDRC DDR2 LP Compliance Test Application Methods of Implementation ...
Page 10: ...10 DDR2 LP Compliance Testing Methods of Implementation ...
Page 46: ...2 Preparing to Take Measurements 30 DDR2 LP Compliance Testing Methods of Implementation ...
Page 70: ...3 Measurement Clock Tests 54 DDR2 LP Compliance Testing Methods of Implementation ...
Page 224: ...14 Clock Timing CT Tests 208 DDR2 LP Compliance Testing Methods of Implementation ...
Page 270: ...15 Data Strobe Timing DST Tests 254 DDR2 LP Compliance Testing Methods of Implementation ...