Summary
In this article we'll explore the all-important Bill of Materials (BOM), what it is, what it's used for and some common mistakes that can be avoided when sending it to your contract manufacturer.
PCB data packages often contain dozens of files in multiple formats. It may seem daunting, but when you break it down, only the three following pieces of data are required to build a printed circuit board assembly from scratch. There can obviously be countless other forms of data and files containing additional information, but we'll focus on these for now.
- Bill of Materials
- Gerber Files (RS-274X)
- Pick and Place / XY Coordinates / Centroid Data
Components and Where They Go
At its core, a Bill of Materials is simply a list of components and where they are supposed to go. Let's take a look at an example of one.
| ID | Qty | Part# | Mfg | Mfg PN | Description | UM | Designators |
|---|---|---|---|---|---|---|---|
| 1 | 3 | EX-87 | AVX | 08055C103KAT2A | CAP, CER, 0.01 UF, X7R, 10%, 50V, 0805 | Ea | C1, C2, C3 |
| 2 | 10 | EX-177 | AVX | 08053A102KAT2A | CAP, CER, 1000 PF, NPO, 10%, 25V, 0805 | Ea | C4-C13 |
| 3 | 4 | EX-191 | Kemet | C1210C106K5RACTU | CAP, CER, 10 UF, X7R, 10%, 50V, 1210 | Ea | C14 |
| 4 | 1 | EX-11 | KOA | RK73H2ATTD4642F | RES, THK FLM, 46.4K, 1%, 100V, 0805 | Ea | R1 |
| 5 | 10 | EX-11 | KOA | RK73H2ATTD1003F | RES, THK FLM, 100K, 1%, 100V 0805 | Ea | R2-R11 |
| 6 | 1 | EX-244 | Molex | 22-05-3031 | CONN, HDR, 0.1 SP, 3 POS, R/A | Ea | J1 |
| 7 | 2 | EX-12 | Fairchild | LL4148 | DIODE, 100V, 200MA, LL4148, SOD80 | Ea | D1, D2 |
| 8 | 1 | EX-180 | TI | TL331IDBV | IC, COMPARATOR, SINGLE, TL331IDBV, SOT23-5 | Ea | U1 |
| 9 | 1 | EX-767 | Analog Devices | ADSP-BF561SBBZ600 | IC, MCU, BLACKFIN 600MHZ DUAL-CORE PBGA297 ROHS | Ea | U2 |