What DVT proves
EVT shows that the engineering works. DVT shows that the product as it will be sold meets every requirement: function, performance, durability, safety, compliance and appearance. Parts should come from production tooling, the electronics should be at their intended final revision, and the firmware should be close to release.
The end of DVT is normally the design freeze. After it, changes should be limited to fixes for issues found in DVT and to process adjustments in PVT. A design still moving at the end of DVT is not ready for PVT. See the EVT, DVT and PVT guide for how the stages connect.
What a DVT build looks like
- Quantity: larger than EVT, often from several dozen to a few hundred units. The reliability test plan and the sample needs of each certification set the number.
- Mechanical parts: from production molds after the first trials (T1 and later rounds), in final materials, colors and textures where possible.
- Assembly: increasingly on the factory floor with factory operators, which gives an early view of assembly problems, though not yet at production rate.
- Test: the first use of production-intent test stations, even if fixtures are still being refined.
- Firmware: feature-complete or close to it, because results such as battery life and radio performance depend on how the firmware drives the hardware.
A typical DVT test matrix
| Test area | What it shows | Notes |
|---|---|---|
| Functional and performance | Requirements met across a sample of units | Test enough units to see variation, not one |
| Environmental: temperature, humidity, thermal cycling | Behavior and survival across rated conditions | Profiles come from the use case and relevant standards |
| Mechanical: drop, vibration, button and hinge life | Durability in handling and use | Include packaged drop and transit tests |
| Ingress protection, where claimed | Whether the claimed IP rating is met | Test to the specific IP code you intend to state |
| ESD and EMC | Immunity and emissions | Often run alongside formal certification |
| Electrical and battery safety | Safe behavior in normal and fault conditions | Lithium battery transport testing (UN 38.3) is a separate requirement |
| Regulatory testing | Market access, such as FCC authorization or the test reports behind CE and UKCA marking | Formal reports are usually issued on DVT units |
| Cosmetic | Finish, color, gaps and flushness within limits | Agree limit samples now, before PVT |
Not every product needs every row, and some categories need more, such as skin-contact material testing for wearables or biocompatibility evaluation for medical devices. Start from the requirements and target markets, then choose the tests. The certification planning guide covers the regulatory side.
DVT exit criteria
- Every requirement is verified with evidence, or has a documented and accepted deviation.
- Reliability tests are complete, and every failure has a root cause and a verified fix.
- Certification is passed, or scheduled with low remaining risk.
- Tooling is accepted for dimensions and cosmetics, or remaining corrections are minor and scheduled.
- Cosmetic limit samples and the golden sample are agreed with the factory.
- The BOM and drawings are released under change control.
Common DVT mistakes
- Using DVT to finish the design. Large changes during DVT invalidate tests already run, and often the certification.
- Testing too few units. One passing unit says little about variation, and failures that occur in a small percentage of units will not appear in a tiny sample.
- Skipping packaged drop and transit tests. A product that survives bare drops can still be damaged in its carton.
- Changing components after certification. A new radio module, antenna or battery cell can require retesting. Check before approving any substitution.
Where Zefinity helps
During DVT, Zefinity’s Launch service coordinates test plans with your OEM/ODM partner, follows failures through root cause and corrective action, and checks exit criteria before PVT starts. See Launch: navigate NPI and scale production.
Frequently asked questions
Is design validation the same as design verification?
In formal quality systems they differ: verification checks that the design meets its specifications, and validation checks that the product meets user needs in its intended use. In hardware build naming, DVT is spelled out both ways. What matters is that the DVT plan covers both the specifications and the real conditions the product will be used in.
Can DVT units be sold?
Generally not. They may differ from the final product in cosmetic or minor functional details, many are consumed by destructive tests, and they are not built under full production controls. Units from PVT, built on the production line to the frozen design, are the first that are commonly sold, provided they pass outgoing inspection.
What is design freeze?
Design freeze is the point after which the design changes only through a formal change process, usually to fix defects. For most hardware it comes at the end of DVT, because the reliability tests, certification and tooling acceptance completed in DVT all assume that design.