AMS AS6221: Accurate Digital Temperature Sensor for Wearable Devices

ams announced the launch of the AS622. Per the company, the AS622 is the world’s most accurate digital temperature sensor. 

The AS6221 achieves measurement accuracy of ±0.09°C, over a temperature range from 20°C to 42°C, making it ideal for the measurement of human body or skin temperature. Also, per the company, no competing digital temperature sensor on the market today can achieve accuracy better than ±0.10°C. 

The AS6221 is housed in a WLCSP package with a footprint of just 1.5mm x 1mm and draws 6µA at an output data rate of 4Hz. Stand-by current is just 0.1µA.

This compact and low-power sensor is well suited to battery-powered portable and wearable devices, such as premium lifestyle or fitness monitoring wristbands, and smart watches. In high-end computing systems and servers, it also enables the regulation of the operation of the processor to maximize system throughput while avoiding overheating.  

The introduction of the AS6221 extends ams’ position in the market for health monitoring technology, alongside existing products such as the AS7038RB blood oxygen monitoring device, AS7030B biosensor, devices for medical imaging systems, and the NanEye family of image sensors for endoscopy. 

The accuracy of the AS6221 is specified across the device’s entire supply voltage range of 1.7V to 3.6V. According to the company, by contrast, the most accurate competing sensors can only achieve their highest accuracy at a single voltage point, producing less accurate outputs across the rest of their operating voltage range. 

The sensor offers a short measurement conversion time of 35ms. Its full operating temperature range is -40°C to 125°C. 

A complete digital temperature sensor system, the AS6221 requires no calibration or linearization. It provides its measurement outputs via a standard I²C interface and includes eight I²C addresses. 

The AS6221 also offers an alarm function, to alert the user when a temperature threshold is crossed. The temperature value for the alarm function may be set by a host processor via the device’s register instruction set. 

Some highlight features of the sensor include:

• High-temperature accuracy of ±0.09 °C (20…42 °C)
• Ultra-low-power consumption: 6 µA at 4 SPS (typ.) and 0.1 μA in standby (typ.)
• Small form factor WLCSP package: total size 1.5 × 1.0 mm
• No calibration or linearization required
• A fully-digital system with up to eight I²C addresses
• Programmable Alert OUT pin:
• No need to constantly poll the sensor
• Best-in-class accuracy
• Space-saving with ultra-small integration size
• Superior power efficiency for better battery endurance
• Easy-to-use solution for fast go-to-market
• Enables multi-device application development
• Easy to integrate with a standard serial bus connection
• Alert functionality for advanced system power reduction

The application of the AS6221 cuts across all fields including medical, wearables, mobile health, fitness trackers, and all sort of electronic devices.