DDR2(+LP) Compliance Testing Methods of Implementation
141
Single-Ended Signals Overshoot/Undershoot Tests
9
Test References
See Table 24 - AC Overshoot/Undershoot Specification for Address and Control Pins and Table 25 -
AC Overshoot/Undershoot Specification for Clock, Data, Strobe and Mask Pins, in the
JEDEC
Standard JESD79-2E
.
Also See Table 24 - AC Overshoot/Undershoot Specification for Address and Control Pins and Table
25 - AC Overshoot/Undershoot Specification for Clock, Data, Strobe and Mask Pins in the
JESD208
.
Also see Table 88 - LPDDR2 AC Overshoot/Undershoot Specification in the
JESD209-2B.
PASS Condition
The measured minimum voltage value for the test signal should be less than or equal to the
maximum undershoot value.
The calculated undershoot area value should be less than or equal to the maximum undershoot area
allowed.
Measurement Algorithm
1 Set the number of sampling points to 2M samples.
2 Sample/acquire signal data and perform signal conditioning to maximize the screen resolution
(vertical scale adjustment).
3 Use T
MAX
, V
MAX
to get a timestamp of the minimum voltage on all regions of acquired waveform.
4 Perform manual zoom on waveform to minimum peak area.
5 Find the edges before and after the Undershoot Point at the GND (
~
0V) Level in order to calculate
the maximum undershoot length duration.
6 Calculate Undershoot amplitude.
Undershoot amplitude = 0 - V
MIN
.
7 Calculate the undershoot area (V-ns)
a
Area of calculation is based on the area of calculation of a triangle where the undershoot width
is used as the triangle base and the undershoot amplitude is used as the triangle height.
b
Area = 0.5 * base * height.
8 Compare the test results with the compliance test limits.
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 ...