Domino scan architecture and domino scan flip-flop for the testing of domino and hybrid CMOS circuits

摘要

Several hybrid CMOS circuit configurations that include both static CMOS logic and Domino CMOS logic are described. Each circuit configuration includes two registers that surround the Domino logic to allow that logic to be tested. One of the registers receives an input test vector that can either be loaded directly through a primary set of inputs or by a serial scan chain if the inputs to the register are not directly accessible. The second register is used to latch the results of the test vector application. The contents of this register can then either be read directly through a primary set of outputs if there is no static CMOS logic between the outputs of the register and a primary set of outputs of the circuit, or scanned out of the second register using a serial scan chain. A Domino scan flip-flop is also described that produces significant transistor count reduction over conventional static scan flip-flops. These Domino scan flip-flops can be used in the Domino logic as sequential elements to allow a multiplicity of logic functions to be implemented using Domino logic. These scan flip-flops can then be serially connected either as part of a separate scan chain or integrated into a single scan chain with the registers and any other static scan flip-flops in the circuit. These Domino scan flip flops allow all of the nominal logic to be tested in conjunction with the two registers. A relationship between a Domino clock that is used to drive the Domino logic in a system clock that is used to drive the static CMOS logic is described which ensures that a correct test data is applied and read out from the hybrid circuit.