FEC200 IR Test
The IR test can be very simple. In the sample below the voltage and current are both moderate. The default test time will be fine. The test voltage is explicitly stated. Finally the presence of the default 10K limiting resistor will have negligible effect. (1ľA * 10K = 10mV)
- TESTn IR 50V <1ľA
The examples below show some of the many variations possible and in some cases necessary. The first example shows an IR test at a fairly low voltage with a high IR limit where the 1V drop in the 10K limiting resistor would be very significant. The F2 in the test description removes the resistor for this test only. Please note that if the test voltage had been 4V or lower, MAXX would have removed the resistor for you.
- TESTn IR 5V <100ľA F2
In the next example the IR limit is very low. In this case you may need more than the default last time. This is not necessarily so. That depends on the degree of accuracy that you require and also on such other factors as the presence of high voltage tests done previously or tests that significantly heat the DUT. We assume here that you need very good accuracy and that some degrading influence may be present. We have therefore increased the soak time to 100mS. In situations like this you may need to evaluate the effect of extra soak time on the accuracy and on the throughput.
- TESTn IR 10V <2NA T100
A very powerful feature is the ability to measure IR at a percentage of the measured VZ (or VBR). There are two ways to do this. The first example measures IR at a percentage of LASTVZ. LASTVZ is an internal variable that MAXX sets whenever a VZ type test is performed. In this case "LAST" means "most recent." Assume in this example that a VZ or VBR test has been done earlier in the sequence.
- TESTn IR 95% <20NA
Sometimes the "LASTVZ" is not the value you wish to use. You might for example want to use a VZ test result early in the sequence before some other test, which, may have pushed the VZ up or down. The next example is a special form of IR test where you may specify the number of the previous test to be used to find the VZ. X is the number of the other test, which is assumed to have been performed before n. Be careful that a conditional jump has not prevented test x from being performed.
- TESTn IR% 95% x <50NA
Suppose the IR limit is <1.2ľA but you are logging data and want to be able to see the readings of rejects that may be greater than full scale (1.6383ľA in this case). You can add a value for the highest expected reading, which will force MAXX to use a higher scale.
- TESTn IR 6V <1.2ľA 5ľA
Of course you can use double-ended limits, conditional jumps or other options as with most other tests. For example:
- TESTn IR 95% >50NA <300NA JFx
SLAVE tests can be used with IR to add additional test limits.