Chip supports mixed-signal test bus

A device jointly developed by LogicVision and National Semiconductor has been successfully deployed in Lockheed Martin's remote-controlled prototype test and fault isolation system.

A device jointly developed by LogicVision and National Semiconductor has been successfully deployed in Lockheed Martin's remote-controlled prototype test and fault isolation system.

Using the STA400 chip (the industry's first ever mixed-signal integrated circuit fully supporting the new IEEE Standard 1149.4 mixed-signal test bus), Lockheed Martin was successful in testing an evaluation circuit board representative of a typical application containing both analogue and digital circuitry using its intranet to control a test system located remotely in Sunnyvale, California.

Engineers were able to remotely probe the circuit board in real time using an online 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 is 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 analogue 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 ICT and allows denser board layouts.

Analogue test points can be accessed according to the 1149.4 standard, which defines parametric test facilities and use 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 unique capability of the STA400 device, electrical test is now possible at the analogue 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 analogue and digital circuitry utilising their intranet to control a test system located in Sunnyvale, California remotely from the Fleet Ballistic Missiles (FBM) facilities at Kings Bay, Georgia and Bangor, Washington".

"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 leverage of embedded test capabilities at the board level", said Steve Baird, LogicVision's marketing director.

"We are excited about Lockheed Martin's success and encourage other system providers to explore the downstream benefits of the IEEE mixed-signal test bus embedded in application-specific devices, such as the STA400.

We foresee incorporation of 1149.4 into future Scorpoverview01/OC devices".

"National Semiconductor is a leading supplier of system test access (STA) enabled analogue and mixed-signal products and technologies", said Brian Stearns, technical marketing manager of National's enhanced solutions group.

"Our joint development partnership with LogicVision allows Lockheed Martin to conduct successful fast, low cost, and highly accurate remote system tests in a real-world situation".

(This was Electronicstalk's Top Story on 20 February 2002).

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