11
Differential Signal AC Output Parameters Tests
182
DDR2(+LP) Compliance Testing Methods of Implementation
V
OLdiff(AC)
- Test Method of Implementation
V
OLdiff(AC)
- Differential AC Output Logic Low Voltage.
The purpose of this test is to verify that the low level voltage value of the test signal within a valid
sampling window must be within the conformance limit of the V
OLdiff(AC)
value as specified in the
JEDEC specification.
The value of V
DDQ
(which directly affects the conformance limit) is set to 1.2V for the compliance
limit set used. You may choose to use the User Defined Limit feature in the application to perform
this test against a customized test limit set based on different values of V
DDQ
.
Signals of Interest
Mode Supported: LPDDR2 only
Signal cycle of interest: READ
Signal(s) of Interest:
• Data Strobe Signal (supported by Data Signal)
Signals required to perform the test on the oscilloscope:
• Pin Under Test, PUT - Data Strobe Signals
• Supporting Pin - Data Signals
Test Definition Notes from the Specification
Test References
See Table 83 - Differential AC and DC Output Levels in the
JESD209-2B
.
PASS Condition
The worst measured V
OLdiff(AC)
shall be within the specification limit.
Measurement Algorithm
1 Acquire and split read and write bursts of the acquired signal.
2 Take the first valid READ burst found.
3 Find all valid Strobe negative pulses in this burst. A valid Strobe negative pulse starts at the 0V
crossing on a valid Strobe falling edge and ends at the 0V crossing on the following valid Strobe
rising edge.
4 For the first valid negative pulse, zoom in on the pulse so that it appears on the oscilloscope’s
display and perform the V
BASE
measurement. Take the V
BASE
measurement result as the
V
OLdiff(AC)
value.
5 Continue the previous step for the rest of the valid Strobe negative pulses that were found in the
burst.
6 Determine the worst result from the set of V
OLdiff(AC)
measured.
Table 114
LPDDR2 Differential AC and DC Output Levels
Symbol
Parameter
LPDDR2-1066 to LPDDR2-200
Units
Notes
V
OLdiff(AC)
AC differential Output low measurement level (for output SR)
-0.25 x V
DDQ
V
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 ...