TEST & MEASUREMENT FEATURE


eye diagrams of the target rank only, an area-based trigger can be used to capture and display only the signals from the target rank. As shown in Figure 5, square areas A1 and A2 are positioned to exclude the lower-amplitude strobe signals, and hexagonal area A3 is placed at the centre of the eye and sized to exclude the lower-amplitude data signals. Using this trigger configuration, eye diagram analysis on the signals from the desired rank can be isolated and better targeted for analysis.


ranks or slots within a DDR memory array. Figure 4 shows an eye diagram display of a DDR3 DQS strobe signal in yellow and a DQ data signal in blue. Because the DDR3 data and strobe lines are shared by multiple components on the bus, there are two distinct amplitude levels of both the strobe and data eyes. The higher amplitudes correspond to the target rank within the memory array, while the lower amplitudes correspond to another rank. In such a verification test, there is a


need to acquire millions of data bits in the eye diagram, but only bits from the desired or target rank. To evaluate the


Figure 4. DDR3 data and strobe lines are shared by multiple components on the bus, creating a need to set a trigger to only capture bits from the target rank


Figure 5 (right).


Trigger areas are positioned to exclude lower-amplitude strobe signals


CAPTURING EVENTS Area-based trigger systems provide the ability to isolate and capture events of interest in order to identify the root cause of failure on a DDR memory interface. This flexible tool can eliminate many hours involved with setting up the oscilloscope and collecting and sorting through thousands of acquisitions for the event of interest. Tektronix offers complete solutions for DDR test debug and applications including Electrical, Logic and Performance validation.


“Area-based


trigger systems provide the ability to isolate and capture events of interest in order to identify the root cause of failure on a DDR memory interface”


Tektronix www.tek.com/technology/ddr-test Enter 675


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