Thinking Beyond a Single Platform In Circuit Strategy

Big iron in circuit testers have been sold for years as a “does everything” platform: analog in circuit; digital vector (backdrive) test, vectorless test, ISP programming, boundary scan, instrumentation-based functional test, etc.

Unifying all these tasks promises to simplify and standardize the test group’s task, no matter what unexpected new technologies product designers may send their way. There’s no additional equipment to justify to management and to buy. The staff is already trained in using the system. The big iron tester vendor says, “Just add some optional hardware and software, and you’re ready to go.”

But reality is always more complicated.

• Your big iron tester is not the latest model and requires an expensive computer upgrade before you can add on the accessories you want.
• New channel cards such as those needed for ISP programming mean you have to modify the test fixture wring.
• A suite of boundary-scan tests have been developed but the tester requires those tests to be “translated” into the tester’s native vector language environment.
• Integrating new routines such as boundary-scan or ISP programming into existing in circuit programs takes a long time because modifying program files affects numerous other files, as well.
• You discover that the big-iron tester can program only one ISP device at a time; drastically slowing throughput.
• The quoted price for the tester upgrades comes in much higher than you anticipated.

The Two-Stage In Circuit Board Test Strategy

At first, it seems counterintuitive, but implementing new tests on a new, low cost platform can drastically simplify the overall task, speed throughput and cost far less than trying to integrate everything on your big iron tester. How?

• The flexible second platform is architected for simplicity
• The hardware for programming serial ISP chips is compact and located right in the fixture for high speed and clean signals
• The platform uses third party boundary-scan software and hardware directly without complicated translations and re-debugging.
• Test software generation and debug is straightforward.
• You can program multiple ISP devices in parallel at effectively data book speeds, speeding throughput.
• The entire package (test platform, fixture and software) costs less than three or four big iron test
  fixtures.

See how a high-volume manufacturer used the Two-Stage Strategy to increase productivity.