The newly-announced TMP117x digital temperature sensor is a 16-bit, single-chip device that offers an accuracy of ±0.1°C over wide temperature ranges.
There are two members of this family so far, the TMP117 and the TMP117M, which is specifically designed for medical applications. Both devices are compatible with the I2C and SMBBus™ interfaces, providing direct temperature readouts. They require no calibration during manufacturing, contributing towards faster design time and allowing the opportunity to lower an overall system’s part count.
The single-chip TMP117 digital temperature sensor. Image used courtesy of Texas Instruments
Both devices consume only 6.3 μW. This is almost 95% less than platinum resistance temperature detectors (RTDs). This makes the TMP117 suitable for remote IoT applications. For the TMP117M in medical applications, the low power dissipation may prevent inaccuracies caused by self-heating in typical temperature sensors.
TMP117: Industrial Applications
The TMP117 is for non-medical industrial applications and offers similar performance to (RTDs). Guaranteed accuracy is:
- ±0.1°C from -20°C to +50°C.
- ±0.15°C from -40°C to +50°C.
- ±0.2°C from -40°C to +100°C.
- ±0.25°C from -55°C to +125°C.
- ±0.3°C from -55°C to +150°C.
The readout is direct, with no need for linearization software and no acquisition error.
Block diagram for the TI TMP117. Image used courtesy of Texas Instruments
Achieving this performance with a platinum resistance temperature detector (RTD) required expensive, precision components that required fine-tuning, simulation, and calibration. TI states that the TMP117 family should reduce this complexity.
TMP117M: Medical Applications
The TMP117M supports the ASTM E1112 and ISO 80601 standards for medical thermometers. Over a temperature range of 30°C to 45°C, covering the entire range of human body temperature, accuracy is within ±0.1°C.
Eval Board Available
The TMP117EVM evaluation board gives engineers the opportunity to familiarize themselves with every nook and cranny of the TMP117. The perforated PCB makes it easy to attach the evaluation board to the device under design and the provided GUI allows further orientation.
The TMP117 digital temperature evaluation board. Image used courtesy of Texas Instruments
Both devices are available in 6-pin WSON no-lead packaging.