A digital method for testing embedded switched capacitor filters

The ever increasing integration of analogue and digital functions on the same IC has increased enormously the problem of testing these complex circuits. Many analogue functions are implemented using switched capacitor techniques whose inputs and outputs may be difficult to access. This paper describes a built in test technique for testing embedded SC filters. The technique proposed is called M-sequence testing and has the advantage that much of the test hardware required can be realised from registers in the digital part of the circuit.