Technical data

• V
High
= V
Term
+ 1 V
• V
Low
= V
Term
+ 0.9 V
If the port is correctly terminated while in this state, the output levels are returned
to the original levels.
N O T E
If V
Term
is greater than 1.5V, the protection algorithm is not active.
In an automated test environment, the algorithm may introduce up to 200ms delay
time when switching the DUT. You can avoid the protection algorithm from
becoming active when switching the DUT (and thus enhance the test throughput).
Speed DUT Switching
At the end of a test when the DUT is ready to be changed, proceed as follows:
1
If V
Term
< +1.5V, adjust a high level that is less than 1V below V
Term
(V
High
<
V
Term
+ 1V). This prevents the protection algorithm from becoming active.
For example, if V
Term
= 1.0V, you have to make sure that the high level is 2.0V
or less. The following command shows how you set the high level of the Data
Out port to 1.25 V:
SOURce1:VOLTage:HIGH 1.25
If the termination voltage is higher than +1.5V, no voltage levels need to be
adjusted (the algorithm is not active).
2
Remove the tested DUT and connect the next DUT.
3
Restore both high level and low level.
4
Start testing the new DUT.
N O T E
Make sure that all Data Out and Clock Out ports are terminated. If not, the protection
algorithm may become active.
3 Recommended Programming Techniques
20 Agilent J-BERT N4903B High-Performance Serial BERT