Functional Test
eXpert has a built-in automatic test vector generator (ATVG) which controls 160 digital input pins (signal generators). Each driver is connected through a resistor to a test socket and to 160 digital output pins (output detectors). The output detector can produce a cyclic redundancy check (CRC). This CRC can be used to verify that the outputs from a device under test are fault free. If the test socket is empty the logic signals at the output detector are the same as the signals generated by eXpert. In this case, the CRC can be used as a self test to verify that the tester is operational. When the test socket is not empty the device being tested will determine the CRC responses.

True Fault Grading
While other fault grading systems rely on simulators and models, eXpert can use Programmable Logic Devices (PLDs) to prepare a real true fault report based on actual hardware. eXpert can produce the true fault coverage for both JEDEC test vectors and the built-in eXpert vectors:

1. eXpert programs a device and then tests it with both JEDEC vectors and eXpert vectors. The test results are saved.
2. The process begins again with eXpert reprogramming the device, toggling the first fuse to a fault state.
3. The device is then retested with both JEDEC vectors and eXpert vectors. The test results are saved.
4. The process repeats with eXpert reprogramming the device, this time toggling the second fuse to a fault state.
5. eXpert repeats this loop over and over again until every fuse is checked in its incorrect state by both JEDEC vectors and eXpert vectors.
6. The results of the thousands of tests are then tabulated and reported by eXpert.

The true fault report is often surprising. JEDEC vectors have been shown to leave hundreds of fuses untested. The eXpert vectors may leave some untested fuses. Increasing the number of eXpert vectors increases our fault coverages with a minimal increase in test time. In any event, hand written vectors can be added to the eXpert vectors resulting in 100% test coverage every time.

DC Parametric Measurements and Testing
During functional or vector testing, load resistors are used to isolate the output signals of the device under test (DUT) from the logic level at the outputs of the pin drivers. For instance, if the pin driver output is high and the DUT output is low, there will be logic high on one side of the load resistor and a logic low on the other side. A current equal to this voltage difference divided by the load resistor value will flow through the load resistor. Using the solid state multiplexer and the highly accurate current/voltage source, it is possible to set the voltage or current stimulus at any load resistor node. The response can then be measured with the digital volt meter.

AC Parametric Measurements and Testing
Up to 33,000,000 vectors per second can be applied to the DUT using the eXpert's built-in generator. When using eXpert vectors the computer sets up the test by setting the number of vectors to use, setting the test frequency and then runs all tests in hardware, no additional delays are introduced by the internal P.C. The computer than waits for an end of test signal to check the result. With an empty socket the test frequency can be increased until eXpert fails a self-test. The self-test fails when the time between tests is less than the time required for the test signal to travel from the input generator to the output detector. This maximum "no part" test frequency is determined partly by the "clock to output" and "set up time" of the logic components used to build eXpert's vectors and CRC logic circuits. Additional time is required for the test signal drivers drive the RC network created by the load resistor and the distributed capacitance of the test socket adapter. The total no part test time is about 30 microseconds. If a device is inserted into the test socket then the maximum frequency will be reduced because of the propagation delay added by the device under test. The difference in maximum test frequency can be used to accurately compute the propagation delay. It is possible to set up the propagation delay measurement to measure delay from any device input signal pin to any device output signal pin. eXpert uses programmable clock signals for testing the AC parameters of registered devices.

Built-in PLD/PROM Programmer
eXpert includes a built-in hardware-based programmer to complement eXpert's test features by allowing program and test in one insertion. No "multiplexer relays" are used. eXpert's programming times are some of the fastest on the market. "Smart" programming algorithms with the built-in "on the fly" test features give eXpert the potential of providing the fastest programming times for a given applications. eXpert can program up to four devices at a time with nearly no additional programming times required. eXpert is intended for use as a high quality, high-volume, application-dedicated programming system. eXpert is not a cheap universal programmer. For customers with high-volume prouduction requirements, eXpert is an unbeatable cost/speed/performance programming system.