December 2020 FAQ: Electrical Testing


Take a look at some of our most frequently asked questions:

Q:  What does DC Testing Cover?

A: Usually only the first few transistors of each pin

Q:  What is DC Testing good for?

A: Electrical Over Stress, Pin damage, IDD power supply current failures

Q:  What does AC Testing do?

A: AC testing will tell you the speed at which things happen in the device like:

  • How long does it take to access an address (access time).
  • How long does it take for one signal occur after another (prop. delay).
  • Maximum operating frequency.
  • Signal rise and fall times.
  • But AC testing by itself, while better than just DC testing, still only tests a small percentage of the die at any one time.

Q:  What is Functional Testing?

A: Functional testing is making sure that all of the functions that a device can perform are exercised

Q:  What type of Testing takes the longest to execute?

A: Functional Testing -the functional test area of a complex parts accounts for 50% to 90% of the overall test development effort and cost.

Q:  How should a comprehensive test plan be executed?

A: A comprehensive test plan should cover all the major areas of the part

  • DC Tests
  • AC Test
  • Functional Tests – Functional tests will cover all the functional blocks of the device and account for a significant part of the cost.

Q:  Are there different test development protocols for different kinds or semiconductors?

A:  Yes, for example, the approach to develop test programs for Microprocessors, FPGAs and Memory are all different.