test time
**Test time** is the **duration required to electrically test each device** — a critical cost driver, typically 1-10 seconds per device, with faster test reducing cost but potentially sacrificing coverage, requiring optimization to balance speed, cost, and quality.
**What Is Test Time?**
- **Definition**: Seconds required to test one device.
- **Typical**: 1-10 seconds depending on complexity.
- **Impact**: Directly determines test cost and throughput.
- **Trade-off**: Faster test vs comprehensive coverage.
**Why Test Time Matters**
- **Cost**: Test time directly determines cost per device.
- **Throughput**: Faster test means higher capacity.
- **Equipment**: Shorter test time reduces tester count needed.
- **Competitiveness**: Lower test cost improves margins.
**Test Time Components**
- **Contact/Load**: Device loading and probe contact (0.5-2s).
- **Functional Test**: Logic and functional patterns (1-5s).
- **Parametric Test**: DC and AC measurements (0.5-2s).
- **Unload**: Remove device and index to next (0.5-1s).
**Optimization Strategies**
- **Parallel Testing**: Test multiple devices simultaneously.
- **Pattern Reduction**: Minimize test vectors while maintaining coverage.
- **Adaptive Testing**: Skip tests for known-good devices.
- **Faster Equipment**: Invest in higher-speed testers.
**Economics**
```python
test_cost_per_unit = (tester_cost_per_hour / 3600) * test_time_seconds
# Example: $500/hr tester, 5s test = $0.69 per device
```
**Best Practice**: Optimize test time to minimum needed for target quality level, balancing cost and coverage.
Test time is **a key cost driver** — optimizing it without sacrificing quality is essential for competitive manufacturing economics.