APPLICATION NOTE 7423

Using 1-Wire for Flexible Electro-Mechanical Contact Applications


Abstract: This application note goes over the basics of using 1-Wire devices to create electro-mechanical contact solutions. It then provides example use cases and an example assembled module.

Introduction

Adding electronic functionality to traditional nonelectronic peripherals and consumables is a common application requirement. This is typically driven by system requirements, including storage of calibration data, manufacturing information, or original equipment manufacturer (OEM) authentication of the peripheral, accessory, or consumable. In addition to selecting the proper IC feature set to provide security and memory for these applications, a reliable and cost-effective solution is needed to attach the IC to the peripheral and make an electro-mechanical connection between the peripheral and host system.

For standard flat surfaces Maxim offers a patented 1-Wire® Contact Package solution, also referred to as an SFN package. Maxim currently offers three different size options for this package, providing a cost-effective method for attachment of a 1-Wire IC to the nonelectronic peripheral combined with a reliable electro-mechanical contact surface.

1-Wire SFN contact package dimensions (mm), bottom viewFigure 1. 1-Wire SFN contact package dimensions (mm), bottom view.

Beyond the SFN Package

For applications that require attachment to flexible surfaces, contoured surfaces, or simply larger connecting contacts, Maxim's 1-Wire ICs can be utilized in an IC plus flexible printed circuit board (PCB) module solution. The reduced pin count of the 1-Wire interface simplifies the number of contacts of a module solution to just two contact pads for IO and GND. With the addition of an adhesive back, these flexible modules can then be easily applied to most surfaces.

Real-World Example

Example flexible moduleFigure 2. Example flexible module.

Example circuitFigure 3. Example circuit.

Example applications using the flexible moduleFigure 4. Example applications using the flexible module.

Choosing a Flex PCB Supplier

Customers who need assistance in finding a PCB supplier for these type of module builds can contact Maxim and request for more information through the following link:

techsupport@maximintegrated.com

Table 1. Typical 1-Wire Devices for Use with Electro-Mechanical Contact Packaging

Product Interface Memory Size Security
DS28E38 1-Wire 2Kb ECDSA-P256 authentication
DS28E50 1-Wire 4Kb SHA3-256 authentication
DS28E16 1-Wire 256 bits SHA3-256 authentication
DS24B33 1-Wire 4Kb Secure serial number
DS2431 1-Wire 1Kb Secure serial number
DS28E05 1-Wire 896 bits Secure serial number

Reference

Trademarks

  • 1-Wire is a registered trademark of Maxim Integrated Products, Inc.