Monitor watches eight analogue voltages

National Semiconductor has added an analogue voltage monitor to its industry-leading portfolio of communication interface boundary scan products.

National Semiconductor has added an analogue voltage monitor to its industry-leading portfolio of communication interface boundary scan products.

The low-power SCANSTA476 analogue voltage monitor is controlled via the IEEE1149.1 (JTAG) bus, and is capable of accurate measurement or sampling of up to eight analogue or mixed-signal input channels for verification of power supply and critical reference voltages on printed circuit boards.

Until now, the pervasive and versatile JTAG bus has been a strictly digital tool, commonly employed at the printed circuit board and system level for structural test, FPGA configuration, Flash memory programming and emulation.

The SCANSTA476 expands the JTAG capability into the analogue realm by simplifying measurement of mixed-signal or analogue voltages.

"System test, FPGAs, Flash memories and system monitoring have made the JTAG bus pervasive in a broad range of applications", said Jeff Waters, product line director for the Communications Interface division at National.

"National's SCANSTA476 extends the utility of this existing infrastructure to the analogue world, greatly facilitating the implementation and use of analogue voltage monitoring by system designers".

Analogue voltage monitors are valuable during all phases of the electronic equipment life cycle, including hardware development, environmental test, production and health monitoring in fielded systems.

In advanced electronic systems with online system self-monitoring features, the SCANSTA476 expands the reach of the monitoring capability to mixed signal voltages for live system health checks or embedded fault observation and prediction.

System designers who use JTAG techniques to debug prototype boards will now benefit from having access to analogue nodes.

This benefit also extends to those performing production tests in the factory and to hardware in the field.

For high-availability systems that require continuous monitoring, designers can now use the existing JTAG bus for embedded analogue measurement.

The SCANSTA476 is a low-power, analogue voltage monitor used for sampling or monitoring up to eight analogue and mixed-signal input channels over a range of 0 to +5.5V.

It provides 2mV of typical measurement accuracy at the full scale range of +5.5V.

By adding this component to the board, multiple point voltages can be accessed even when extensive EMI (electromagnetic interference) shielding is used or there is no physical access to the board.

In production test, physical access has become more difficult for traditional probing techniques, such as in-circuit or flying probe testers, yet board complexity and semiconductor packaging density continues to increase.

The SCANSTA476 enables voltage monitoring to be embedded into the electronic system, supplementing existing JTAG test techniques and permitting more advanced monitoring functions.

It also extends the lifecycle of the electronic system by reducing field service and maintenance costs, while improving system availability with innovative health monitoring features.

Available now in a very small LLP-16 package, the SCANSTA476 analogue voltage monitor is priced at $3.50 each in 1000-unit quantities.

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