Intellitech's PT100 Parallel Tester maximizes

PCB test and configuration throughput

Patent-pending technology reduces cost of test for PCBs with high

production line 'beat rates' and long test times

The tester itself is not a traditional tester with a back plane and fixed number of test channels, but a collection of self-contained 'parallel tester card' building blocks that connect together over flexible ribbon cable.   The PT100 Parallel Tester cards are housed in a 19" 3U height rack mountable box with room for 16 plug-able cards, each one supporting 24 re-configurable tester channels and one IEEE 1149.1 controller.  Each 19" rack of 16 parallel tester cards can then be connected to another 19" rack of PT100 tester cards, expanding the tester channels as physical space and AC power permits.  The physical flexibility of the tester enables it to interface with a variety of UUTs from small cell phones to large telecom blades.  The 24 tester channels and 1149.1 interface have a programmable logic high output level from .8v to 5V with a current drive of up to 84ma.  The IEEE 1149.1 interface can deliver and test boundary-scan data to and from the UUT at 64 Megabits per second on each tester card simultaneously.  Each tester card also has a high-speed clock channel that supports a clock rate up to 500Mhz for use with at-speed Built-In Self Test on the UUT. 

The tester cards are controlled from a single PC console using either Intellitech's PXI or PCI card interface and Intellitech's Scan Executive manufacturing software. The software comes standard with integrated support for adding PXI, GPIB or VISA instruments and power-supplies needed for testing the UUTs.   A secondary connector exists with auxiliary I/O that support integrating the parallel test process with automated board handlers and external fixturing.  Test development and debug is done with the company's Eclipse Test Development Environment.  All the tests developed for testing a single PCB can be exported without modification to the Intellitech Parallel Test environment.

Benefits of the PT100 Parallel Tester over Boundary-Scan on In-Circuit Testers

"Boundary-Scan Test on ICT is a strategy to reduce handling time, where as Intellitech's Parallel Tester is a strategy to reduce the total test and configuration time", said CJ Clark, Intellitech's CEO and past IEEE 1149.1 chairperson. "For PCBs with long configuration and test times relative to the handling time, the highest throughput per dollar can be achieved more cost effectively by optimizing the test and on-board programming time, not just the handling time.  ICT is a 'one-at-a-time' approach.  PCBs with long digital test times are better tested in parallel after a simple analog ICT test or a low cost MDA type test", Clark added. 

For certain products, especially when on-board FLASH or CPLD programming is desired, the digital test and configuration times can be 10-30 times longer than the analog test time and the handling time combined.  Customers are already reporting ICT test times greater than two minutes for some PCBs.  Of that two-minute test time, a small fraction is analog test time for passives and the remainder is digital boundary-scan test and configuration time.  This type of PCB may spend 10 seconds or so in analog test on the In-Circuit Tester and then need 110 seconds of boundary-scan based test and configuration. If this boundary-scan test is performed on the ICT, then this approach shifts a lower-cost (IEEE 1149.1) test technique onto the higher dollar ICT capital equipment.  Since only one or two medium sized PCBs can be tested at a time with this approach, then multiple boundary-scan on ICT stations are needed to keep up with the line rate.  This increases the test costs and reduces the throughput.

Platform for at-speed and functional test after boundary-scan test

"No one in the industry is saying, 'Let's integrate AXI or AOI with ICT so we can save a handling step', as these are different and separate test techniques", said Clark.  "Integrating boundary-scan controllers on ICT test platforms should be done with caution, only certain low volume products or products with short digital test times on ICT that can be performed fast enough to keep up with the production line rate will benefit from combining the two test techniques.  Without calculating mathematically which approach to take, you could end up increasing your test costs by integrating the two."

While boundary-scan test can be performed on in-circuit test platforms, just because it can be done, doesn't mean that it should be done.  The product type and product's digital and analog test time should be the determining factors if boundary-scan on ICT or parallel boundary-scan is the proper approach.  A product with high digital fault coverage, long on-board programming times and at-speed test requirements should be considered for test and configuration separately from ICT.   Certain products with long digital test and configuration times (products with FPGAs, on-board FLASH or needing at-speed tests) will benefit from being tested simultaneously with the Intellitech PT100 Parallel Tester.

"For some PCBs we see IEEE 1149.1 test and on-board programming as separate technique from MDA/ICT style tests and either a separate step or a step closely coupled with the functional test," said Clark.  "AXI, AOI, parallel boundary-scan and functional test may be all that is needed for certain types of PCBs.  Take for instance a CPU based PCB with multiple high pin-count FPGAs. After AXI and AOI, the PT100 Parallel Tester can perform boundary-scan structural tests on 25-30 PCBs simultaneously, then in parallel download CPU based functional test code to the CPU's FLASH memory, have each CPU execute on-board functional tests simultaneously, capture the results and then in parallel, erase the FLASH and download, the product's real operation code" added Clark.  "Even though this test and configuration may take several minutes, all of this can be done with a single Intellitech PT100 Parallel Tester keeping up with a rate of one PCB every 10 seconds" Clark stated.

"Our customers are already running at-speed memory tests in the 200Mhz range", said Mike Ricchetti, Intellitech CTO.   "A pogo-pin ICT fixture is not the environment you want to run these types of tests on.  The environment is noisy, and each pogo-pin will affect the signal integrity on the PCB.  In addition, the power delivery is unnaturally distributed over the PCB and is not delivered the way it would be during normal functional operation. The subtle differences in in-rush current, the instantaneous current needed during switching, can affect high-speed testing results.  As the need for testing on-PCB gigabit SERDES interfaces increases, the pogo-pin fixture will become less appropriate for these types of high-speed tests", Ricchetti pointed out.

The parallel test patent was filed in the US and worldwide in July of 2001.   "The Intellitech PT100 Parallel Tester's second patent-pending method, called Clark's equation, balances handling time with test time", added Mike Ricchetti.  "Even though the PT100 could do it, we're not saying you should test one thousand PCBs simultaneously, that doesn't take into account handling time.  In it's simplest form, Clark's equation says that given a fixed bandwidth for a tester, the number of UUTs that should be tested in parallel is equal to the test time of the UUT divided by the handling time. Therefore, for a PCB with 240 seconds of test and on-board programming and 12 seconds of handling time (to barcode the PCB and get the PCB onto and off of the tester), the total number of PCBs to test in parallel is 20.  A single Intellitech PT100 Parallel Tester can then keep up with a production 'beat rate' of one of these PCBs every 12 seconds or more."

More information can be found at http://www.intellitech.com/products/paralleltest.asp

Pricing and Availability

The Intellitech PT100 Parallel Tester hardware is available now from stock. The base tester hardware with just four (4) cards is approximately $9,750.00.  Each additional tester card is approximately $1,800.00. Contact Intellitech at http://www.intellitech.com for various options. 

Intellitech is a registered trademark of Intellitech Corp.  PT100 Parallel Tester is a trademark of Intellitech Corp.