| Nome: | Descrição: | Tamanho: | Formato: | |
|---|---|---|---|---|
| 199.12 KB | Adobe PDF |
Orientador(es)
Resumo(s)
Measuring the values of discrete components frequently takes place during
the test or debug phase of Printed Circuit Boards (PCB). This operation
requires tools that are based on some access type. The shrinking geometries
constrain the straightforward use of tools based on physical access. One of the
aims of the IEEE1149.4 Std. is to facilitate those on-board measurements. This
infrastructure relies on electronic access that includes high quality analog
buses and a set of electronic switches, which enable to completely isolate a
component under characterization, e.g. by injecting a known current and
measuring the voltage across it. During this process, the infrastructure
switches have a negative impact in the measurement accuracy. This paper
analyses the measurement of one resistor in two situations: connected
between a pin and ground and between two pins. The infrastructure switches
that affect the measurement quality are identified and the upper limit of its
systematic error is characterized. When the systematic error is completely
defined then it is possible to remove its negative effect from the final result.
Descrição
Palavras-chave
Debugging PCBs