Chip enables Intranet-based probing

LogicVision and National Semiconductor have successfully deployed their jointly developed STA400 device in Lockheed Martin’s remote controlled, prototype test and fault isolation system.

Using the STA400 chip – claimed to be the industry’s first mixed-signal IC to fully support the new IEEE Standard 1149.4 Mixed-signal Test Bus – Lockheed Martin successfully remotely probed a circuit board in real time using an on-line schematic diagram of the PCB, measuring actual voltages at component pins.

Advances in circuit board and IC packaging technology have resulted in extraordinary reductions in circuit board area. With smaller, denser boards, test access has been compromised, and fault detection and diagnosis have been limited.

Digital portions of circuit boards presently benefit from extensive use of the familiar IEEE 1149.1 boundary scan standard for high-fault coverage automated test generation, and low-cost PC-based board test. To access analog test points, however, an external In-Circuit-Tester (ICT) must still be used, and the board layout and shielding must accommodate external probing. The IEEE 1149.4 mixed-signal test bus standard reduces the need for an ICT and allows denser board layouts. Analog test points can be accessed according to the 1149.4 standard, which defines parametric test facilities and uses the digital 1149.1 infrastructure.

LogicVision and National Semiconductor have been working together for the last two years to develop and promote technology based on the 1149.4 standard. LogicVision provided RTL code for the 1149.4 embedded test core and some unique design concepts to extend circuit bandwidth. National Semiconductor incorporated the LogicVision IP into its STA400 device that it is currently sampling to selected customers.

‘With the capability of the STA400 device, electrical test is now possible at the analog nodes, which previously could not be accessed without time-consuming custom design,’ said Pat McHugh, Lockheed Martin’s DFT Applications Engineer in their EPI Division.

‘Lockheed Martin was successful in testing an evaluation circuit board representative of a typical application containing both analog and digital circuitry using their Intranet to control a test system located in Sunnyvale, CA remotely from the Fleet Ballistic Missiles facilities at Kings Bay, GA and Bangor, WA.’

‘In validating the use of 1149.4 as an enabling technology for remote control test and diagnosis of a mixed-signal circuit board, Lockheed Martin has demonstrated the embedded test capabilities at the board level,’ said Steve Baird, LogicVision’s director of business development.