August 4, 2005 -- Design for testability (DFT) works to make a circuit more testable to ensure that it was manufactured correctly. Alfred Crouch explains the purpose of DFT in his book, Design-For-Test for Digital ICs and Embedded Core Systems: "To exhaustively test a combinational circuit with N inputs, a sequence of 2N test vectors must be applied and observed to fully exercise the circuit." With that goal in mind, the primary purpose of DFT is to increase testability of a given netlist by increasing controllability and observability.

By Udhaya Kumar. (Kumar is a project manager in Physical Design for eInfochips, Ltd.)