Introducing CPL Part Numbers

During the development of the Common Parts Library (CPL), we reached a point where we wanted to uniquely identify a generic CPL part such as a 10kΩ resistor or a 12MHz crystal oscillator. This entailed creating a numbering scheme for each generic part.

But before creating a new part numbering scheme, we took a look at how manufacturer part numbers (MPNs) are defined to see what we can learn. A Panasonic 10kΩ 0603 resistor is ERJ-3EKF1002V and a Vishay 47 µF capacitor is 293D476X9016D2TE3. What is the reason that they are given these MPNs? Let’s take a look.

1. A lot of information is ‘hidden’ inside the part numbers, something which can usually be decoded only after going through a data sheet. For example, for the resistor ERJ-3EKF1002V, ‘3EK’ refers to the 0603 package size, ‘F’ refers to the variation (1%), and ‘1002’ refers to 10k.
2. Prefixes have special meanings. For the resistor ERJ-3EKF1002V, ‘ERJ’ internally means to be thick film chip resistors for Panasonic. Sometimes, the prefixes could refer to the manufacturer itself. ‘LT’ is common for Linear Technology and ‘MAX’ is for Maxim. However, the well known MAX232 is manufactured by both Maxim and Texas Instruments.
3. Most part numbering schemes are unique to a manufacturer, and if you choose a different one, it’s a completely different scheme. For example, if we had decided to use Yageo’s RC0603FR-1310KL resistor instead, the scheme is different.

Below is a picture from a datasheet which shows us the process of ‘decoding’ the information:

The MPNs are not always easy to interpret, and as we developed a scheme for identifying generic parts in the CPL, these are the lessons we took from the MPN naming schemes:

1. The part numbers should encode useful information.
2. The part numbers should be readable without having to consult an external reference.
3. The naming should be consistent across component types.

We also considered the wisdom of a comic from xkcd:

We’re not trying to redefine MPNs. The generic CPL part numbers are identifying something new: generic part descriptors which refer to a set of parts with different MPNs which satisfy the same function. The generic CPL part numbers have following properties:

1. The prefix ‘CPL’ is used to indicate that these are generic parts from the Common Parts Library.
2. Each piece of information is hyphen separated for easy reading.
3. The type of component (RES, CAP, MCU etc) is encoded in the position immediately following ‘CPL’, and additional attributes are listed after that.

A generic 10k resistor is CPL-RES-0603-10K-0.1W which includes information about the part type (RES), package size (0603), value (10K) and power rating (0.1W). A generic 1nF capacitor is CPL-CAP-C0G-0603-1NF-50V which includes information about the part type (CAP), dielectric type (C0G), package size (0603), value (1nF) and voltage rating (50V).

CPL part numbers are now visible on the main page. You’ll be able to easily link to a particular CPL part by copying the links next to each CPL part, as you can see below:

Let’s look at an example of how this referencing can be used. If you were assembling a list of components needed for A4988 motor driver, the following is a way to link to the part without having to mention specific MPNs and then consulting datasheets:

1. 1 x CPL-MDR-STEPPER
2. 4 x CPL-CAP-X7R-0603-100NF-50V
3. 4 x CPL-RES-0603-10K-0.1W
4. 1 x CPL-RES-POT-10K-0.1W
5. 2 x CPL-RES-1206-0.05-1W

It’s quite a big challenge to invent a new part numbering scheme, but we think that this initial effort is a good step forward. We want to hear your comments and suggestions. Drop us a note below or reach out to us at cpl@octopart.com or in the CPL community forum!