Question
My customer would like to test the output current of AD8532 by ATE. Could he
force external voltage then use the ATE to test the output current. Would you
pls give some suggestion on it?
Answer
For +Isc, typically we will set the test up as an Voh test where we swing the
part to the positive rail and then force the output to 0V with an external V/I
supply while measuring the short circuit current. This can also be done by
forcing the output to the negative supply voltage while measuring the current.
I think we generally just force the output to 0V. For -Isc, just swing the
device to the negative rail, ground the output and measure the output current.
For Iout, it is a little less clear because I can't remember the last product
that has actually had this tested at ATE. The approach I would probably take
is similar to Isc. I would try swinging the amplifier to it's positive rail
(Voh), then apply the Iout current listed on the datasheet (in the case, apply
a negative or sink current), then measure the output voltage to see if it still
meets it's output swing specs. Reverse everything for -Iout. As an example,
the ADA4004-4 datasheet has an Iout spec of 10mA with Vout at 13.6V. In this
case, the Vout of 13.6V is the typical for Voh. I would think the Vout we
would really want to look for is the actual minimum Voh spec that we normally
test for. One problem to consider here is the effect of any contact resistance
at the supply pin and output pin with a 10mA Iout current. One Ohm of contact
resistance would cause 10mV. For this reason, it would be important to measure
Voh or Vol differentially from the supply pin to the output pin.