TIDUDW4B January   2019  – December 2024 CC2640R2F , TMP117

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
    3. 2.3 Highlighted Products
      1. 2.3.1 TMP119
      2. 2.3.2 CC2340R5
    4. 2.4 System Design Theory
      1. 2.4.1 Shelf Life and Active Life
      2. 2.4.2 Wearer Comfort
      3. 2.4.3 System Accuracy
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Required Hardware and Software
      1. 3.1.1 Hardware
      2. 3.1.2 Software
        1. 3.1.2.1 Reading From the Patch
    2. 3.2 Testing and Results
      1. 3.2.1 Test Setup
        1. 3.2.1.1 Current Consumption and Life Span
      2. 3.2.2 Test Results
        1. 3.2.2.1 Current Consumption and Lifespan
  10. 4Design Files
    1. 4.1 Schematics
    2. 4.2 Bill of Materials
    3. 4.3 PCB Layout Recommendations
      1. 4.3.1 Layout Considerations for the CC2340R5
      2. 4.3.2 Layout Considerations for the TMP119
        1. 4.3.2.1 WCSP (YBG) Package
      3. 4.3.3 Layout Prints
    4. 4.4 Altium Project
    5. 4.5 Gerber Files
    6. 4.6 Assembly Drawings
    7. 4.7 Related Documentation
    8. 4.8 Trademarks
    9. 4.9 Revision History

1 System Description

With the need to integrate sensors into newer wireless and cloud applications, the Bluetooth-enabled, high-accuracy skin temperature measurement flex patch provides a wireless answer for receiving high-accuracy skin temperature measurements on a Bluetooth-capable device, such as a smart phone or tablet.

Through direct contact with the skin, the TMP119 high-accuracy, low-power, digital temperature sensor can send 16-bit digital output data through the I²C to a CC2340R5 SimpleLink™ Bluetooth Low Energy wireless microcontroller (MCU). After collecting this data, the CC2340R5 can use Bluetooth protocol to transmit the data to a Bluetooth-connected device.

The patch is designed to operate with a 3V coin cell battery, requiring very low power consumption of the design components. For testing and demonstration purposes, the designer can use the large contact pads of the device to receive external power from other sources when a battery is not connected.

There are two primary modes of operation for the patch: active and inactive mode. When the patch is inactive, the CC340R5 enters a complete shutdown state and the TMP119 is powered down. This mode allows a multiple year shelf life for the patch without a significant depletion of stored energy in the battery. When the designer presses the wake-up switch, the flex patch enters active mode and the TMP119 begins reading and auto-advertising temperature data the CC2340R5 Bluetooth Low Energy device can receive.

In healthcare applications, reuse or extended use of monitoring patches can pose risks to patient health due to hygiene concerns. An alternative for temperature-monitoring systems is to use a removable covering that can be disposed of after use. This is common in designs of probe-type thermometers for oral temperature measurements. If this method is used, the system and these covers must be characterized as the final design. For probes, the designer can modify the software to move between active and inactive mode, but an MCU must be in the probe to use Bluetooth communication protocol under this modification.