What is DFT?

What is DFT ?

DFT stands for Design for Testability. It's a set of design techniques used in digital integrated circuit (IC) design to make it easier to test whether a chip is working correctly after manufacturing.

Why DFT is needed:

Chips are super complex (millions to billions of transistors).

Manufacturing defects can occur.

You can’t manually test every internal signal.

So, you need built-in mechanisms to test them automatically.

Common DFT techniques:

Scan Chains – Makes internal flip-flops accessible for testing.

ATPG (Automatic Test Pattern Generation) – Tools generate test vectors to detect faults.

BIST (Built-In Self Test) – Circuit tests itself using internal logic.

Boundary Scan (JTAG) – Used to test interconnections between chips on a board.

Goal of DFT:

Improve test coverage.

Reduce test time.

Enable early detection of defects, saving time and cost in production.