Specifying an electronic load looks simple on paper — match the DUT's voltage and current range — but the ATLAS series' three voltage platforms (150V, 600V, 1200V) and thirteen power tiers per platform (2kW to 60kW) exist precisely because getting the match wrong in either direction creates real problems.
The Three Numbers That Actually Matter
Maximum voltage must exceed the DUT's highest operating voltage with reasonable margin, including overshoot, ripple peaks, and open-circuit conditions.
Maximum current must exceed the highest current the test profile requires, but running near the absolute ceiling continuously is poor practice — sizing with headroom (70-80% of maximum for sustained operation) extends usable life.
Total power is voltage × current, but most loads have a derated operating region at combinations of very high voltage and current simultaneously — check the actual power-vs-voltage-vs-current envelope in the datasheet.
Why Oversizing Has Real Costs
Resolution and accuracy typically scale with range. A load specified for 2400A resolves current with less precision at a 5A test point than a load specified for 20A. Cost scales roughly with power rating, so unnecessary capacity is unnecessary spend.
Why Undersizing Is the More Common Failure Mode
- Future test program growth as next-generation DUTs draw more current
- Transient/peak current requirements exceeding steady-state current substantially
- Derating at elevated ambient temperature versus published maximum ratings
Scaling Beyond a Single Module
For power requirements beyond a single rack's capacity, ATLAS modules support parallel expansion to 600kW. Confirm master-slave synchronisation behaviour, whether mixed power tiers are supported, and that total system response time doesn't degrade as more modules are added.
Specification Checklist
- List worst-case voltage and current including transients and overshoot, not just nominal ratings
- Check the actual power-vs-voltage-vs-current operating envelope, not just headline figures independently
- Size with realistic headroom (roughly 70-80% of max current) rather than the absolute ceiling
- Factor in test program growth over the load's expected service life
- For paralleled systems, confirm synchronisation architecture and mixed-tier support
Finch Electronic Solutions — Melbourne, Australia
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