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.