Selecting a Microcontroller: Part 2 – Cost

Dennis Cecic, P. Eng. (d.cecic@ieee.org)
Senior Member, IEEE Toronto Section

In this article, we will uncover cost considerations in selecting a microcontroller.

Bill-of-materials (BOM) cost is usually the most important constraint in a design effort, and as an engineer, you should always strive for the lowest BOM cost in your designs.

“An Engineer is someone who can do for $1 what anyone else can do for $2”

You might think that 16 or 32-bit MCUs are expensive, however, since these are usually fabricated on a newer process technology, they can be more cost effective than older “legacy” MCUs. The following table compares 100-piece USD pricing for our Hero MCUs:

Fig. 1. MicrochipDirect 100 pc USD pricing on our Hero MCUs (Sept. 2020)

Notes:

  • 8-bit MCUs (PIC16F1) are very cost effective and should always be considered for high-volume applications
  • PIC32MZ device has 128x the RAM of the PIC16F1 device, but only 4x the cost
  • PIC24F device hits a sweet spot between cost/performance and is suitable for battery-powered applications!

Pricing and Availability

My usual go-to stocking distributor is Digikey or Mouser. You know an MCU is “really” in production when it’s in stock at one of these distributors! They ship overnight to most major cities and handle the duty fees for you.

Microchip also have their own self-serve online store, called MicrochipDirect, where you can manage orders and access other value-added services, such as customized firmware programming.

FindChips.com

This is a wonderful online resource to check availability of a specific manufacturer part number with all major distributors. The following image shows availability of the PIC16F19197-I/PT MCU:

Fig. 2. FindChips.com Search Results (PIC16F19197-I/PT) (Sept. 2020)

Using MAPS for Pricing

Microchip Advanced Product Selector (MAPs) can be used to rank selected MCU devices based on price. Once you have narrowed your search to a few devices using the Parameter Search window, configure the tool to sort the results by price using the pull-down menu as shown:

The tool will then automatically sort the devices by price from top (highest) to bottom (lowest):

Next, scroll through the Search Results window to find an MCU of interest, then click on it. The tool will populate the device parameters window for the part, highlighting key device specifications, development tools, available technical documentation, and budgetary pricing:

Click on the “Budgetary Pricing” tab to display the pricing:

The listed budgetary pricing should match or be very close to pricing found on MicrochipDirect.com.

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