2 Note

Using Voltage Identifier (VID) Signals
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4.2 Using Test Head Loads
Test head loads (pull-ups/pull-downs) improve the detection of opens. With the
switch pair OFF, the signals would be pulled to a logic level low if test head pull-
downs are used and a logic level high if test head pull-ups are used. Using pull-ups
with the Low Side switch ON would receive a logic level high on the signal if the signal
or GND connection were open and a logic level low if they were not open. Using pull-
downs with the High Side switch ON would receive a logic level low on the signal if the
signal or VCCP ball were open and a logic level high if they were not open.
Note: On-board pull-up/down resistors must be taken into consideration when test head
loads are used.
Table 6 - Test Head Loads
Low Side
Control
High Side
Control
Signal Test Head
Load
0 0 0 Pull-Down
0 0 1 Pull-Up
1 0 0 Pull-Up
0 1 1 Pull-Down
1 1 N/A
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