A rectifier-based power stage fails in the field for a small set of reasons, and the reasons are nearly all visible before the board ships. The ten-check audit turns that knowledge into a release gate: ten questions, each with a pass criterion and a trace to the design method that answers it. This article presents the ten-check matrix, works through the first five checks — ratings, derating, thermal, surge, and layout — then the second five — snubber, test, documentation, sourcing, and field plan — adds the severity weighting and review cadence, and closes by showing the plan as a reusable design review template.
The Ten-Check Audit in One Table
The audit is a table before it is anything else, and the table is the release gate. Each row is a check, the pass criterion, and the design article that justifies it.
| # | Check | Pass criterion | Authoritative method |
|---|---|---|---|
| 1 | Ratings | Ratings clear the worst operating point | Voltage-ratings method |
| 2 | Derating | Margin applied to voltage, current, temperature | Derating rules |
| 3 | Thermal | Junction under limit at worst ambient | Thermal design guide |
| 4 | Surge | Pulse energy fits the rating | Surge testing |
| 5 | Layout | Loops small, grounds clean | PCB layout guide |
| 6 | Snubber | Ringing and spike damped | Flyback snubber |
| 7 | Test | Waveform verified under load | Field test method |
| 8 | Docs | Ratings, tests, and revisions recorded | Incoming inspection |
| 9 | Sourcing | Second source qualified | Sourcing strategy |
| 10 | Field plan | Failure modes reviewed against mission | Failure-mode guide |
The table is the whole audit in one view, and the checks trace to the authoritative articles of this planning cluster. The field reliability checklist article already documents the reliability side; this article adds the severity weighting and the review cadence that makes it a gate.
Checks 1-5: Ratings, Derating, Thermal, Surge, and Layout
The first five checks cover the electrical and physical design, and each one is a pass-or-fail question with a number behind it.
Check one, ratings: do the rectifier’s voltage and current ratings clear the worst operating point — the rail peak, the load peak, and the surge? The rectifier voltage ratings method supplies the calculation. Check two, derating: is the margin applied to voltage, current, and temperature, with the real ambient and duty? The derating rules make the margin explicit. Check three, thermal: does the junction stay under its limit at the worst ambient with the worst duty? The thermal design guide provides the junction equation. Check four, surge: does the pulse energy of the worst event fit the rectifier’s surge rating? The surge testing article defines the event. Check five, layout: are the AC and DC loops small, and are the power and signal grounds clean? The PCB layout guide is the layout authority.
The first five checks are the design’s electrical skeleton. A board that passes all five has the ratings, the margin, the heat, the surge, and the layout in place — the foundations the field actually kills. The checks are mechanical because they should be: each one is a number a reviewer can verify.
The five checks also protect against the two most expensive failures a design review can make. The first is the false pass – a check that looks complete because the nominal corner passes, while the hot corner or the surge corner fails; the audit defeats this by demanding the worst-case number, not the nominal one. The second is the orphan design – a design with no record, no second source, and no field plan, which cannot be reproduced or serviced when it ships; the audit defeats this by making the documentation and sourcing checks part of the gate rather than an afterthought. The rectifier failure modes guide and the sourcing strategy article are the authorities that the false-pass and orphan defenses trace to.
Checks 6-10: Snubber, Test, Docs, Sourcing, and Field Plan
The second five checks cover the protection, the verification, and the supply chain — the parts of the design that field failures and field recalls actually come from.
Check six, snubber: is the ringing and the spike damped at the operating point? The flyback snubber design covers the RCD and RC options. Check seven, test: has the waveform been verified under load, not just on the bench? The test method and the ripple diagnosis guide form the verification. Check eight, documentation: are the ratings, the tests, and the revisions recorded so the design is reproducible? The incoming inspection article shows the record discipline. Check nine, sourcing: is a second source qualified, so the board keeps shipping if one supplier fails? The sourcing strategy covers the qualification flow. Check ten, field plan: have the likely failure modes been reviewed against the mission? The rectifier failure modes guide is the review authority.
The second five checks are where the release gate lives: a board can pass the electrical design and fail the field because the snubber was guessed, the test was skipped, the docs vanished, the source dried up, or the failure mode was never considered. The audit catches all five before the door.
The second five checks also carry the field knowledge that the first five cannot: the first five prove the design is correct on paper, and the second five prove it survives the world. The snubber check is where the paper design meets the real waveform, because the ringing and the spike are circuit-dependent and only the scope reveals whether the damping actually holds. The test check is where the bench meets the load, because the no-load and full-load behaviors differ exactly in the places the design assumed. The documentation, sourcing, and field-plan checks are where the single design becomes a repeatable product: the records let the next engineer reproduce the choice, the second source keeps the board shipping, and the field plan names the failure modes the mission can hit. The field reliability checklist article and the rectifier failure modes guide form the field-knowledge half of the audit, and the incoming inspection article covers the documentation half.
Severity Weighting and Review Cadence
The ten checks are not equal, and the severity weighting is what makes the audit a gate rather than a checklist to be rushed. The weighting allocates the review effort to the checks that stop the field failure.
The high-severity checks are the thermal, the surge, and the test: these are the checks that, when missed, produce the field failures and the safety issues — an overheated junction, a surge that kills the part, a repair that only worked on the bench. The medium-severity checks are the ratings, the derating, the snubber, and the field plan, which degrade the reliability and the life. The low-severity checks are the layout, the documentation, and the sourcing, which matter for the long term and the supply rather than the immediate failure. The review cadence follows the weighting: the high checks are reviewed at every design gate, while the low checks are reviewed at the major milestones. The field reliability checklist article and the thermal cycling guide supply the severity logic.
The weighting also sets the data the review must collect. A high-severity check that cannot be verified — a surge test not run, a thermal check not calculated — is a release blocker, not a review note; a low-severity gap can be tracked. The severity scale is what turns the checklist from a form into a priority.
The severity weightings are best shown as the table that sets the review cadence:
| Severity | Checks | Review cadence | Release action if missed |
|---|
| High | 3 thermal, 4 surge, 7 test | Every design gate | Blocker – not releasable |
|---|
| Medium | 1 ratings, 2 derating, 6 snubber, 10 field plan | Every milestone | Correct before ship |
|---|
| Low | 5 layout, 8 docs, 9 sourcing | Major milestones | Track and close |
|---|
The table turns severity into action: the high rows are the release blockers, the medium rows are the ship-correct items, and the low rows are the long-term trackers. The field reliability checklist article and the thermal cycling guide provide the reliability logic the weighting follows, and the automotive-grade framework raises the bar where the mission is safety-rated.
Using This Plan as a Design Review Template
The final use of the plan is as a template, and the template is the way the audit survives beyond a single project. A design review that runs the ten checks with the severity weighting becomes a repeatable gate.
The template has three parts. First, run the ten checks in order, filling each pass criterion with a number and a reference. Second, weight the findings by severity and decide which are blockers. Third, record the review as the project’s release evidence, so the next design starts from a gate that was already defined. The incoming inspection article shows the record form, and the field reliability checklist article connects the template to the reliability plan. The automotive-grade framework sets the stricter version for the safety-rated designs.
The ten-check audit is the release gate of the rectifier stage. Ratings, derating, thermal, surge, and layout cover the electrical skeleton; snubber, test, docs, sourcing, and field plan cover the field reality; severity weighting keeps the review honest; and the template makes the gate repeatable. A board that passes the ten checks with the blockers cleared has spent its margin deliberately and knows its failure modes — the two things the field actually rewards. The general rectifier category supplies the parts the audit verifies, and the field checklist article is the companion reference.