There is a striking resemblance between tester applications employing people for the handling of devices and applications that utilize robots. In either case, the robot or the person places a device in the socket, signals the tester when ready, and puts the part in an appropriate tray or bin upon completion of the test depending on its outcome. Hence, the functional requirement for high-speed testing is virtually identical to low-speed test requirements. Only the time element is a major difference. Hence, Q’nApp #L12 applies directly to High Volume testing as well, only without sufficient throughput.

An obvious prerequisite to high-speed testing, then, is high throughput, i.e. the number of devices tested per minute. To achieve high throughput, multiple DC PMU’s is a prerequisite. So is deep vector memory.

The ETS family provides up to 16 PMU’s per system. At no time need we operate more than 32 PMU tests in sequence; indeed, judicial selection of pins can significantly reduce the number of test sequences. Indeed, 100 signal pins which requires 100 PMU test sequences with a single DC PMU may require only 4 PMU sequences when using the ETS. Effectively, the PMU tests become nearly 20 times faster! However, there is a diminishing return to adding PMU’s while the cost is proportional to the number of PMU’s.

The ETS series testers has vector memory depth ranging from 128K to 4M. For production testing, 1M of vector memory is often necessary.

Accuracy cannot be dispensed with despite the need for high throughput, lest yield will be reduced. Hence, the PMU’s of the ETS are high precision instruments that only a combination of mechanical relays, high precision resistors (0.05% accuracy), instrumentation op amps, and high resolution DAC’s (12 bits) can produce.

All in all, the ETS system with multiple PMUs is superbly suited to high volume production testing.

Also See:

Q'nApp #L3: The HILEVEL Production Floor
Q'nApp #L11 and #12: The HILEVEL TestBox

QL14.zip is a zipped Word file of this Q'nApp.