How to Prepare a BOM for PCBA Quotation and Production
Prepare a controlled PCBA BOM with exact manufacturer part numbers, designators, quantities, packages, DNP/DNI notes, approved alternatives, and customer-supplied part details.
Engineering review by Huitai Engineering Team
Quick Answer
A production-ready PCBA BOM identifies every fitted component with an exact Manufacturer Part Number, manufacturer, Designator, Quantity, Package, description, and project-specific notes. It should also mark DNP / DNI positions, Customer-supplied parts, Approved alternatives, and no-substitute items. Buyers should release one controlled BOM revision with the matching Gerber, CPL, assembly drawing, and quantity before quotation or production.
BOM preparation defines what must be purchased and assembled. Component shortage strategy belongs in the BOM Risk guide, while technical substitute review belongs in How to Approve Alternative Components for PCBA.
BOM Fields Required for PCBA Review
| BOM field | What to provide | Why it matters |
|---|---|---|
| Manufacturer Part Number | Complete MPN, including the required suffix | Identifies the exact orderable component |
| Manufacturer | Component maker | Separates the part from similarly named devices |
| Designator | R1, C14, U3, J2, and related references | Connects each BOM line to the PCB and assembly data |
| Quantity | Quantity per assembled board | Supports purchasing and placement checks |
| Package | Confirmed package or case code | Helps review BOM, footprint, and CPL consistency |
| Description | Value, function, tolerance, rating, or other useful detail | Helps detect mismatches without replacing the MPN |
| Approved alternatives | Customer-approved substitute MPNs, if any | Records permitted options without authorizing an unreviewed substitution |
| DNP / DNI | Positions that must not be populated | Prevents unintended component placement |
| Customer-supplied parts | Items provided by the buyer, including expected quantity | Separates consigned material from supplier purchasing |
| Special notes | No-substitute, programming, traceability, matching, or handling instructions | Makes project-specific boundaries visible before quotation |
Avoid descriptions such as “10 k resistor” or “MCU” without an exact MPN when the design requires a specific part. Package, tolerance, rating, pinout, firmware behavior, or qualification requirements may differ even when two descriptions look similar.
Use Exact MPNs and Required Suffixes
A suffix may identify package, temperature grade, tape-and-reel format, voltage option, memory size, firmware variant, or another orderable difference. Removing it can make the BOM ambiguous or point sourcing toward a component that is not compatible with the approved design.
Keep manufacturer names and MPNs in separate columns. Do not use distributor stock codes as the only identifier unless the corresponding manufacturer part number is also recorded.
Control DNP, DNI, and Customer-Supplied Parts
Mark DNP or DNI references explicitly and keep those designators aligned with the assembly drawing and CPL. A blank quantity cell is not a reliable instruction because it may be interpreted as missing data rather than “do not populate.”
For customer-supplied components, identify the exact MPN, required quantity, expected overage, delivery status, and any handling or traceability requirement. The quotation should distinguish buyer-supplied material from components included in the BOM Sourcing for PCBA scope.
Record Alternatives Without Skipping Approval
A BOM may list alternatives that the customer has already evaluated. Record the approved MPN and any conditions for its use. Do not use a generic note such as “equivalent accepted” when voltage, tolerance, footprint, pinout, protocol, firmware, or project qualification could change compatibility.
If an alternative has not yet been approved, keep it outside the released BOM or mark it as pending. Use the separate Alternative Component Approval guide to review the technical and customer-authorization steps.
BOM Release Checklist Before Quotation or Production
- Confirm the BOM revision matches the current Gerber, CPL, and assembly drawing.
- Include exact MPNs and required suffixes for all purchased parts.
- Confirm designators and per-board quantities.
- Mark DNP / DNI positions explicitly.
- Identify approved alternatives and no-substitute components.
- Identify customer-supplied parts and the expected delivery quantity.
- Add special programming, matching, handling, or traceability notes.
- State the target build quantity and whether repeat production is expected.
Use the PCBA Quote File Checklist to confirm the complete RFQ package. If availability, lifecycle, MOQ, or repeat-order continuity is the concern, continue to BOM Risk and Component Availability.
FAQ
What is the most important field in a PCBA BOM?
The exact manufacturer part number, including its required suffix, is the primary purchasing identifier. Designator, quantity, package, description, and notes are still needed to connect that part to the assembled board.
Should DNP or DNI components stay in the BOM?
Yes. Keep the references visible and mark them clearly as DNP or DNI so the assembly team does not treat them as missing information or populate them unintentionally.
Can a BOM include approved alternatives?
Yes. List exact customer-approved alternative MPNs and any conditions for their use. A generic “equivalent accepted” note is not enough for parts with compatibility constraints.
How should customer-supplied parts be identified?
Mark them as customer-supplied and include the exact MPN, required quantity, expected overage, delivery status, and any handling or traceability instructions.
What other files should match the BOM revision?
The released BOM should match the Gerber package, CPL or pick-and-place data, assembly drawing, firmware or programming inputs, and testing instructions for the quoted build.
Prepare the BOM for Manufacturing Review
After the BOM fields and revision are controlled, send them with the related manufacturing files instead of asking the supplier to infer missing assembly requirements.