MCP9700AT-E/LT: A Linear Active Thermistor IC for Simplified Analog Temperature Sensing
In the realm of temperature measurement, the challenge has often been to convert a physical phenomenon into an easily readable electrical signal with minimal complexity and cost. The MCP9700AT-E/LT from Microchip Technology elegantly addresses this challenge, offering a highly integrated analog solution that simplifies system design for a wide range of applications.
Unlike traditional NTC thermistors, which exhibit a non-linear resistance curve requiring complex linearization algorithms, the MCP9700AT-E/LT is a linear active thermistor integrated circuit. Its core function is to generate an analog voltage output that is directly proportional to the ambient temperature. This device operates within a wide temperature range of -40°C to +125°C, making it suitable for environments from freezing cold to intensely hot.
The key to its simplicity lies in its output characteristic. The IC provides a typical scale factor of 10.0 mV/°C, meaning the output voltage increases by 10 millivolts for every degree Celsius rise in temperature. With an additional DC offset of 500 mV, the output voltage can be easily calculated using the formula: VOUT = 500 mV + (T°C × 10 mV/°C). For example, at 25°C, the output is a straightforward 750 mV. This linear relationship allows designers to directly connect the output to a microcontroller's analog-to-digital converter (ADC) without the need for additional signal conditioning or lookup tables, drastically reducing code overhead and development time.
Housed in a tiny SOT-23-3 package, the MCP9700AT-E/LT is designed for space-constrained applications. It is exceptionally easy to use, requiring only a single supply voltage between 2.3V and 5.5V and a single bypass capacitor for stable operation, drawing a very low quiescent current of typically 12 µA. This low power consumption makes it an ideal candidate for battery-powered devices such as portable data loggers, environmental monitors, and wearable health trackers. Its robust performance also sees it deployed in HVAC systems, automotive cabin climate control, and consumer appliances.
A notable feature is its calibrated accuracy. The device is factory calibrated, offering an accuracy of ±4°C (max) from 0°C to +70°C and ±2°C (typical) at +25°C, which is sufficient for many applications where monitoring relative temperature changes or thresholds is more critical than absolute precision.
ICGOODFIND: The MCP9700AT-E/LT stands out as a premier choice for designers seeking a no-fuss, reliable, and cost-effective analog temperature sensor. Its linear voltage output, minimal external component requirement, and low power consumption remove significant barriers to implementing temperature sensing, accelerating time-to-market for a diverse array of electronic products.
Keywords: Analog Temperature Sensor, Linear Active Thermistor, Low Power Consumption, Wide Voltage Range, SOT-23 Package.
