How do you calculate power module first-pass yield?

Divide the modules that pass test on the first attempt by the total modules tested, then multiply by 100. With 188 passing out of 200 tested, FPY is 94%.

What is a good first-pass yield for EV charger power modules?

Mature power-electronics lines typically run 95-98% FPY. At 94% against a 96% target you are 2 points short — acceptable for a ramping line but worth a containment look on a steady-state one.

What is the difference between first-pass yield and final yield?

First-pass yield counts only units that pass with zero rework; final yield counts everything that ships after rework. The gap between them is your hidden rework volume.

Why does a 2-point yield gap matter on power modules?

At 200 units, 2 points is 4 extra modules into rework per lot. On a high-value DC module, that rework labor, retest time, and station occupancy compounds fast across a week of production.

What causes low power module first-pass yield?

The usual drivers are solder defects on power semiconductors, gate-driver tuning, high-pot dielectric failures, and connector seating — most are detectable with Pareto analysis of your test-station failure codes.

Does first-pass yield include units scrapped at test?

Yes — any module that does not pass on the first attempt, whether it is reworked or scrapped, counts against FPY. Only clean first-time passes count in the numerator.

EV Charging Infrastructure Manufacturing calculator

Power Module Yield Calculator

Power module first-pass yield (FPY) is the percentage of DC fast-charger power conversion modules that pass functional and high-pot test on the very first attempt, with no rework. Production engineers and quality managers on EV charging infrastructure lines watch it because power modules are the most expensive and most failure-prone subassembly in a charger, and a low FPY means hidden rework cost, test-station congestion, and slipped ship dates. This calculator converts your raw pass/test counts into FPY and shows the gap to your committed target so you can see at a glance whether the line is on plan.

What this calculator does

Calculate first-pass yield for EV charger power modules from modules that pass test versus modules tested.
a quality engineer needs first-pass yield for charger power modules before cabinet integration
It computes first-pass yield as passing power modules divided by tested power modules, then subtracts that from your target to show the gap in percentage points.

Formula used

Power module first-pass yield = passing power modules ÷ power modules tested × 100
Gap to target = target yield - actual yield

Inputs explained

Power modules passing first-pass test:
Power modules tested:
Target power module first-pass yield:

How to use the result

Use it at end of shift, after a production lot, or during a yield-improvement project to track whether power module FPY is meeting the number quoted to program management.
FPY counts only first-pass results, so it ignores units that pass on rework — a line can hit shipping volume while masking a real first-pass problem behind a rework loop.

Current U.S. benchmarks

Global copper trades at $13,484 per tonne (IMF via FRED, May 2026), up 41.5% in a year, and U.S. industrial electricity averages 8.66 cents per kWh. Both feed electrified-hardware unit economics.

Common questions

How do you calculate power module first-pass yield? Divide the modules that pass test on the first attempt by the total modules tested, then multiply by 100. With 188 passing out of 200 tested, FPY is 94%.
What is a good first-pass yield for EV charger power modules? Mature power-electronics lines typically run 95-98% FPY. At 94% against a 96% target you are 2 points short — acceptable for a ramping line but worth a containment look on a steady-state one.
What is the difference between first-pass yield and final yield? First-pass yield counts only units that pass with zero rework; final yield counts everything that ships after rework. The gap between them is your hidden rework volume.
Why does a 2-point yield gap matter on power modules? At 200 units, 2 points is 4 extra modules into rework per lot. On a high-value DC module, that rework labor, retest time, and station occupancy compounds fast across a week of production.
What causes low power module first-pass yield? The usual drivers are solder defects on power semiconductors, gate-driver tuning, high-pot dielectric failures, and connector seating — most are detectable with Pareto analysis of your test-station failure codes.

Last reviewed 2026-05-12.