4. Device Testing and Classification Procedure
The process for testing and classifying a device follows a structured, multi-step approach.
4.1 Test Conditions and Stressing
- Sample State: Devices must have completed all normal manufacturing operations. Prior to ESD testing, they undergo full parametric and functional testing at room temperature.
- Sample Size: A sample of 3 devices is used for stress testing at each voltage level. A separate sample of 3 devices is typically required for each pin combination group to be tested.
- Stress Application: For each specified pin combination, each of the 3 devices is subjected to one positive and one negative pulse. There must be a minimum delay of 1 second between consecutive pulses.
4.2 Pin Combinations for Integrated Circuits
The standard defines four primary configurations for testing all relevant pin pairings. The goal is to test each pin’s susceptibility relative to the device’s power and ground structure.
| Combination | Pin(s) at Terminal A (Pulsed) | Pin(s) at Terminal B (Ground) | Floating Pins (Unconnected) |
| 1 | All pins one at a time, except the pin(s) connected to Terminal B | First power pin(s) | All pins except Pin Under Test (PUT) and first power pin(s) |
| 2 | All pins one at a time, except the pin(s) connected to Terminal B | Second power pin(s) | All pins except PUT and second power pin(s) |
| 3 | All pins one at a time, except the pin(s) connected to Terminal B | Nth power pin(s) | All pins except PUT and Nth power pin(s) |
| 4 | Each Non-supply pin one at a time | All other Non-supply pins collectively (except PUT) | All power pins |
4.3 Failure and Classification Criteria
After the ESD stress is applied, the final classification is determined based on post-stress electrical testing.
- Failure Criteria: A part is defined as a failure if, after exposure to the ESD pulses, it no longer meets the device data sheet requirements as determined by parametric and functional testing. If testing at multiple temperatures is required, it is performed at the lowest temperature first.
- Classification Criteria: To achieve a certain classification, all samples tested must pass the requirements up to the specified voltage level.
- CLASS A: Any part that fails after exposure to an ESD pulse of 200 volts or less.
- CLASS B: Any part that passes after exposure to an ESD pulse of 200 volts, but fails after exposure to an ESD pulse of 400 volts.
- CLASS C: Any part that passes after exposure to an ESD pulse of 400 volts.