Fault modeling and testable design of 2-level complex ECL gates

Bipolar emitter coupled logic (ECL) devices can now be fabricated at very high densities and much lower power consumption. Behaviour of 2-level complex ECL gates is examined in the presence of physical faults. It is shown that the conventional stuck-at fault model cannot represent a majority of circuit level faults. A new augmented stuck-at fault model is presented which provides a significantly higher coverage of physical failures. A testable design approach is presented for on-line detection of certain error conditions occurring in gates with true and complementary outputs which is a normal implementation for ECL devices.<>