Modelling and test generation for MOS transmission gate stuck-open faults
Malika Belkadi, H.T. Mouftah · IEE Proceedings G Circuits Devices and Systems · 1992
The paper presents a testable design for a MOS transmission gate (whether it is a pass transistor or a CMOS transmission gate) when it is isolated (i.e. it does not have transmission gate neighbours nor does it feed a bus) and subject to a stuck-open fault condition in a given CMOS VLSI circuit. The proposed design consists of the original transmission gate to which a MOS transistor is added, so that the high impedance state resulting from a stuck-open fault condition can be eliminated. It is shown that the new approach can be extended to MOS transmission gate-based multiplexers for which a better testing scheme is ensured. We also demonstrate that not all transmission gates need to be augmented by using an additional MOS transistor, so that the circuit under study can be kept combinational while in the test mode. Finally, the test generation for isolated transmission gates in the context of the PODEM algorithm is discussed.