The TMP102AIDRLR Guide: ±0.5°C Digital Temperature Sensor
Overview
TMP102AIDRLR is a low-power digital temperature sensor from Texas Instruments (TI). It is available in a SOT-563 package (1.6 mm × 1.6 mm) and is compatible with SMBus, two-wire, and I²C interfaces. It provides typical accuracy of ±0.5°C without calibration or external component signal conditioning. The device is intended to replace traditional NTC/PTC thermistors and outputs highly linearized digital temperature data, allowing temperature to be determined without complex calculations or lookup tables. Its on-chip 12-bit ADC provides a resolution as low as 0.0625°C.
TMP102AIDRLR operates over a supply voltage range of 1.4 V to 3.6 V, with a maximum quiescent current of only 7.5 µA across the full operating range and a shutdown current as low as 0.35 µA, making it very suitable for battery-powered portable devices and long-running monitoring systems. Its 1.6 mm × 1.6 mm SOT-563 package is 68% smaller than the traditional SOT-23, providing an ideal temperature monitoring solution for space-constrained, high-density PCB designs. The device has a rated operating temperature range of -40°C to +125°C. Production units are 100% tested with NIST-traceable sensor tests and verified using ISO/IEC 17025 accredited calibrations with NIST-traceable equipment.
Chip Specifications, Features, and Application Scenarios
| Part number | TMP102AIDRLR |
| Device Type | Digital temperature sensor (local temperature) |
| Interface Type | I²C / SMBus / two-wire |
| Supply Voltage | 1.4 V to 3.6 V |
| Operating Temperature Range | -40°C to +125°C |
| Accuracy (-25°C to +85°C) | ±2.0°C (maximum) |
| Accuracy (-40°C to +125°C) | ±3.0°C (maximum) |
| Typical Accuracy | ±0.5°C (no calibration required) |
| Resolution | 12-bit (0.0625°C) |
| Temperature Conversion Time | 26 ms (typical) |
| Conversion Rate | Configurable: 0.25 Hz / 1 Hz / 4 Hz / 8 Hz (default 4 Hz) |
| Quiescent Current | 7.5 µA (maximum, operating) |
| Shutdown Current | 0.35 µA (maximum) |
| Package | SOT-563 (DRL, 6 pins) |
| Package Size | 1.60 mm × 1.60 mm (2.56 mm²) |
| Number of Connectable Devices | Up to 4 (on the same bus) |
| Alert Output | ALERT (open-drain, pull-up resistor required) |
| Special Features | One-shot conversion, NIST-traceable, SMBus alert |
Core Feature Analysis
High-precision digital output. The TMP102AIDRLR has a maximum error of ±2.0°C over the -25°C to +85°C range and ±3.0°C over the full temperature range (-40°C to +125°C), with typical accuracy reaching ±0.5°C. Compared with NTC thermistors, its output is a highly linearized digital signal, allowing temperature values to be read directly without complex calculations or lookup tables. It also eliminates the nonlinearity, self-heating effects, and calibration requirements inherent in thermistors.
Ultra-low power consumption. The device's maximum quiescent current in operating mode is only 7.5 µA, and in shutdown mode it is as low as 0.35 µA. With a configurable conversion rate (0.25 Hz to 8 Hz), developers can flexibly trade off between response speed and power consumption according to application requirements. One-shot conversion mode allows the system to wake the sensor when needed to perform a single temperature measurement and then automatically return to a low-power state, making it very suitable for intermittent temperature monitoring scenarios.
Compact package and I²C multi-device support. The SOT-563 package occupies only 2.56 mm², providing ample margin for high-density PCB layout. Through the ADD0 pin, the device can be configured with four different I²C addresses (0x48, 0x49, 0x4A, 0x4B), allowing up to four TMP102 devices to be mounted on the same I²C bus, suitable for systems requiring multipoint temperature monitoring.
ALERT temperature threshold alarm. The device provides an independent ALERT output pin and supports two operating modes: comparator mode (TM=0) and interrupt mode (TM=1). In comparator mode, when the temperature exceeds T_HIGH or falls below T_LOW, the ALERT pin is activated and remains active until the temperature returns to the normal range. In interrupt mode, the ALERT pin is activated when the temperature exceeds the limit, and is automatically cleared after the host reads the temperature register. The ALERT pin is an open-drain output and requires an external pull-up resistor.
Application Scenarios
Portable electronic products. The low power consumption and extremely small package of the TMP102AIDRLR make it an ideal temperature monitoring solution for portable products such as smartphones, tablets, and wearable devices. It can be used for battery temperature monitoring and processor thermal protection.
Power supply temperature monitoring. In DC-DC converters, LDO regulators, and power modules, the device can monitor the temperature of power devices in real time and trigger system derating or protection actions through the ALERT pin when the temperature exceeds the limit.
Computers and laptops. The device's small size and low power consumption make it suitable for CPU/GPU temperature monitoring in laptops, desktop motherboards, and servers, as well as thermal management of hard drives and memory modules.
Battery management systems. In lithium battery packs and battery management systems, the TMP102AIDRLR can be used to monitor battery surface temperature, providing a temperature basis for charge/discharge control and preventing safety issues caused by overheating.
Industrial automation and control. The device is suitable for temperature monitoring in factory automation, test and measurement equipment, and electromechanical equipment. Its wide operating temperature range (-40°C to +125°C) and digital output characteristics give it high reliability in industrial environments.
Medical and healthcare equipment. In medical monitoring devices and portable health devices, the TMP102AIDRLR can provide accurate temperature measurement, and its NIST traceability facilitates applications requiring compliance certification.
Where the TMP102AIDRLR fits — and where it doesn’t
The TMP102AIDRLR is the right choice when the design needs a small, low-power, I2C-compatible temperature sensor for battery-powered or space-constrained applications. Wearable devices, portable medical monitors, battery management systems, industrial control boards, and environmental monitoring all fit. It is also a direct replacement for NTC thermistors in designs where calibration and signal conditioning overhead is a concern.
It is the wrong choice when the design needs temperature accuracy better than ±0.5°C — the TMP112 offers ±0.5°C maximum accuracy and is functionally similar, while the TMP117 provides ±0.1°C accuracy for precision applications. It is also the wrong choice when the design needs an analog output rather than a digital interface, or when the operating temperature exceeds +125°C.
At QIXINWEI (Shenzhen Qixinwei Technology Co., Ltd.), we have spent 13 years supplying Texas Instruments temperature sensors, digital sensors, and the broader signal chain ecosystem alongside full PCBA assembly. If you are mid-selection and want a second pair of eyes on the sensor, the thermal layout, or the supporting components, send the spec or the BOM and we will flag the risks before you commit.
Q1: How is the I²C address configured? How many TMP102 devices can be connected to the same bus?
The TMP102AIDRLR configures its I²C target address through the logic state of the ADD0 pin. When ADD0 is grounded, the address is 0x48 (default); when connected to V+, it is 0x49; when connected to SDA, it is 0x4A; and when connected to SCL, it is 0x4B. Therefore, up to four TMP102 devices can be connected to the same I²C bus. In practice, if the ADD0 pin is left floating, the device will use the default address 0x48, but this practice may cause address instability. It is recommended to explicitly connect ADD0 to GND, V+, SDA, or SCL. Note that if there are other devices on the bus with a default address of 0x48 (such as certain EEPROMs or touch screen controllers), the ADD0 pin level must be changed to avoid address conflicts.
Q2: What is the difference between the comparator mode and interrupt mode of the ALERT pin? How should I choose?
The behavior of the TMP102's ALERT pin is controlled by the TM bit in the configuration register. In comparator mode (TM=0), the ALERT pin acts as the output of a temperature comparator: it is activated when the temperature exceeds T_HIGH and remains active until the temperature falls below T_LOW. This mode is suitable for simple temperature control scenarios that require "trigger when temperature exceeds the limit, reset when temperature falls back." In interrupt mode (TM=1), the ALERT pin is activated when the temperature exceeds the limit, but is automatically cleared after the host reads the temperature register, and will only be triggered again after another limit violation. This mode is suitable for scenarios that require actively querying temperature via I²C and receiving an interrupt notification each time the limit is exceeded. The ALERT pin is an open-drain output and must be externally pulled up to the logic supply through a pull-up resistor (typical value 4.7 kΩ to 10 kΩ).
Q3: How should the accuracy specifications of the TMP102AIDRLR be understood? What is the difference between ±0.5°C and ±2.0°C in the datasheet?
The ±0.5°C mentioned in the datasheet is the device's typical accuracy (without calibration and without external signal conditioning), while ±2.0°C (maximum) is the guaranteed upper accuracy limit over the -25°C to +85°C range. The two are not contradictory: typical accuracy reflects the performance of most devices under normal temperature conditions, while the maximum value is the guaranteed specification over the entire temperature range after accounting for all process variations. In applications requiring high-precision measurement, it is recommended to perform single-point calibration of the system within the actual operating temperature range, which can improve accuracy to within ±0.2°C. In addition, attention should be paid to the self-heating effect caused by the device's own power consumption—at 3.3 V supply and 7.5 µA current, the self-heating power is only 25 µW, and its impact on temperature measurement can be ignored.
Q4: How are the temperature conversion time and conversion rate configured? What impact do they have on system power consumption?
The typical temperature conversion time of the TMP102 is 26 ms. The conversion rate is configured by the CR1 and CR0 bits in the configuration register and can be selected from four options: 0.25 Hz, 1 Hz, 4 Hz, and 8 Hz. The default value is 4 Hz. The higher the conversion rate, the faster the temperature update, but the power consumption also increases accordingly. In power-sensitive battery-powered applications, the conversion rate can be reduced to 0.25 Hz or 1 Hz. In addition, the TMP102 supports one-shot conversion mode, in which the system can trigger a single conversion via an I²C command when needed and automatically return to shutdown state after conversion. This can achieve conversion rates of more than 30 conversions per second, making it suitable for applications requiring intermittent high-frequency sampling.
Q5: What are the key considerations for PCB layout and external components?
Power supply decoupling is the most important layout point. TI recommends placing a 0.01 µF (10 nF) bypass capacitor between the VCC and GND pins, as close as possible to the device's power and ground pins. In systems with high noise or high supply impedance, additional decoupling capacitors can be added. The typical value of the I²C bus pull-up resistor is 4.7 kΩ. If the bus is long or many devices are connected, the resistance can be appropriately reduced (but the bus capacitance limit must be considered). The ALERT pin, being an open-drain output, also requires a pull-up resistor. For the SOT-563 package, the ADD0 pin should be explicitly connected to GND, V+, SDA, or SCL, and should not be left floating. In addition, it is recommended to place the TMP102 close to the heat source (such as near power devices), but avoid direct thermal radiation from other heat-generating components.
Conclusion
The TMP102AIDRLR is a classic device in Texas Instruments' digital temperature sensor product line. With ±0.5°C typical accuracy, a wide 1.4 V to 3.6 V supply range, 7.5 µA ultra-low quiescent current, and an ultra-small 1.6 mm × 1.6 mm package as its core competitiveness, it has established a broad application base in portable electronics, power supply monitoring, battery management, industrial automation, and medical equipment. Its I²C/SMBus digital interface, combined with the configurable ALERT alarm output, enables the system to implement accurate temperature monitoring and protection with extremely low software overhead. NIST traceability further enhances the device's value in applications requiring compliance certification. In actual design, developers should focus on the ADD0 pin address configuration (to avoid bus address conflicts), the comparator/interrupt mode selection of the ALERT pin (determined according to the system response strategy), the tradeoff between conversion rate and power consumption (optimized according to battery life requirements), and the close placement of the 0.01 µF bypass capacitor (to ensure power supply noise suppression). For applications requiring higher accuracy or a wider supply range, the TMP112 and TMP1075 provide pin-compatible upgrade paths; in scenarios with a tight supply chain, the domestic GX112 can serve as a PTP alternative.