ADT7310 | GUILCOR SENSORS

ADT7310
Temperature sensors

High-accuracy digital temperature sensor with fast conversion time and SPI interface for demanding measurement applications.

Maximum precision
+/- 0,25°K

Minimum temperature
-55°C

Maximum temperature
+150°C

Minimum dimensions
4 x 4 x 0,9

Response time

Fast

Drift

Low

Self-warming
Low

Price
High

What is a ADT7310 sensor ?

The ADT7310 is a high-resolution digital temperature sensor with SPI designed by Analog Devices.

It integrates:

an ultra-stable bandgap temperature sensor,
a 16-bit ADC converter,
and a 4-wire SPI interface compatible up to 10 MHz.

It provides linear, accurate, and repeatable measurements without external calibration.

Operating principle

The sensor measures the voltage proportional to the temperature using an internal PN transistor.

This voltage is converted by a 16-bit ADC, digitally corrected, and then transmitted via SPI.

The output is signed (two's complement); each least significant bit represents 0.0078 °C in 16-bit mode.

T(°C) : Value16b x 0,0078

Technical Specifications

Parameter	Typical value
Resolution	16 bits (0,0078 °C / LSB)
Precision	±0,25 K (0 → +70 °C)
Interface	SPI (read/write)
Power supply voltage	2,7 → 5,5 V
Max. SPI Frequency	10 MHz
Conversion time	220 ms
Consumption	210 µA typical
Sleep mode	< 1 µA
Internal records	Configuration, thresholds, sensor ID
Case	MSOP-8 / LFCSP 8 pins
Annual drift	±0,05 K/year

Wiring Configuration

Brooch	Name	Function
1	CS	Chip Select (active low)
2	SCLK	SPI Clock
3	DIN	SPI Input (MOSI)
4	DOUT	SPI Output (MISO)
5	INT	Output interruption (optional)
6	CT	Comparator output (optional)
7	GND	Mass
8	VDD	Power supply 2.7–5.5 V

Self-warming

The self-heating is less than 0.05 °C, even under continuous operation,

thanks to a very low current (210 µA) and an optimized sigma-delta ADC.

Application areas

⚙️ Laboratory instrumentation (calibration benches, metrology)

🧠 Medical applications (incubators, skin sensors, monitoring)

💡 High-precision industrial control

🧱 Drift-sensitive embedded systems

🔬 Reference digital thermometers

Should I choose a ADT7310 sensor ?

Strengths points

🎯 Exceptional metrological precision
→ With an accuracy of ±0.25 K and a resolution adjustable up to 16 bits (0.0078 °C), the ADT7310 outperforms most SPI sensors on the market. Ideal for applications requiring reference accuracy.
🧠 Factory calibration and long-term stability
→ Each sensor is individually calibrated at Analog Devices, ensuring a stability of ±0.05 K/year without external recalibration.
💡 Flexible SPI mode and integrated alarm
→ Fast SPI interface (10 MHz) compatible with 3 or 4 wires, and configurable INT / CT outputs to trigger real-time thermal alert thresholds.

Weaknesses points

💰 Above average cost
→ Its precision and stability come at a price: it is a high-end component, reserved for critical or calibration applications.
🔋 Longer conversion time
→ The 16-bit mode (240 ms) can slow down systems requiring ultra-fast measurement.
📶 Sensitivity to electromagnetic environment
→ Like any precision sensor, it requires special care in routing and filtering to maintain its optimal performance.

Useful information

Here is some useful information regarding the ADT7310 sensors.

Resolution and precision

The ADT7310 offers a configurable resolution of 13 to 16 bits.

In 16-bit mode, each LSB represents 0.0078 °C, making it one of the finest resolutions in its class.

It combines a calibrated silicon junction measurement, a 16-bit sigma-delta converter, and internal compensation ensuring exceptional accuracy.

Parameter	Typical value
Resolution	13, 14, 15 or 16 bits (configurable)
LSB (16 bits)	0,0078 °C
Precision	±0,25 K (−10 → +85 °C) / ±0,5 K (−40 → +125 °C)
Measurement range	−55 → +150 °C
Annual drift	±0,05 K
Conversion time	240 ms
Power supply voltage	2,7 → 5,5 V
Typical current	210 µA
Max. SPI Frequency	10 MHz

🔹 Remarks:

The sensor is fully calibrated at the factory (no external correction required).
The conversion is signed (two's complement), facilitating the reading of negative temperatures.
Compatible with 3 or 4 wire SPI.

Application Example – SPI Reading

The ADT7310 transmits 16 bits during each SPI read.

The bits are signed, with bit 15 representing the sign (1 = negative temperature).

🔹 SPI word structure (16 bits)

Bits	Name	Description
[15]	Sign	0 = + / 1 = −
[14 → 0]	Temperature (15 bits)	Data × (1 / 128 °F)

🔹 Conversion equation

T (°C) = Valeur / 128

Example:

SPI Reading → 0x19A0

0x19A0 = 6560₁₀

T = 6560 / 128 = 51,25 °C

✅ Measured temperature = 51.25 °C

🔹 Resolution modes

Mode	Bits	LSB (°C)
13 bits	0,0625	30 ms
14 bits	0,03125	60 ms
15 bits	0,0156	120 ms
16 bits	0,0078	240 ms

💡 The user can adjust the accuracy / speed via the configuration register (0x01).

Integration into an electronic system

The ADT7310 connects to any standard SPI microcontroller (Arduino, STM32, ESP32, Raspberry Pi, etc.).

It allows for complete configuration via registers: mode, resolution, alarm thresholds, and interrupt.

🔹 Typical components

Component	Function
ADT7310	High-precision SPI digital sensor
Microcontroller	SPI Reading and Configuration
100 nF capacitor	Decoupling on VDD
Pull-up resistor (10 kΩ)	On INT and CS (optional)
RC filter (optional)	For increased EMI immunity
Stable power supply 3.3 or 5 V	Stable thermal reference

🔹 Functional diagram (ASCII)

           +3.3V / +5V
              │
           [ADT7310]
              │
     DOUT ─────► MISO (MCU)
     DIN  ◄──── MOSI (MCU)
     SCLK ◄──── SCK  (MCU)
     CS   ◄──── GPIO (MCU)
     INT  ─────► GPIO (option)
     GND  ───── GND

💡 The INT signal can be configured to alert in case of temperature threshold exceedance.

🔹 Operating Principle

1️⃣ The microcontroller activates CS and sends the read command.

2️⃣ The ADT7310 returns 16 bits corresponding to the temperature.

3️⃣ If the alarm mode is enabled, the INT output goes low when the temperature exceeds the programmed threshold.

4️⃣ The sensor can be put into automatic shutdown between measurements to reduce power consumption.

Practical advantage

Advantage	Description
🧠 Metrological precision ±0.25 K	Ideal for laboratories and critical industries
⚙️ Configurable resolution up to 16 bits	Allows for adjusting speed and accuracy
💡 Programmable alarm mode (INT/CT)	Autonomous surveillance without active MCU
🔋 Low consumption (210 µA)	Compatible low energy systems
🔧 Universal SPI 3 or 4 wires	Direct interfacing with most MCUs
🧱 Self-calibrated and stable	No calibration required, drift < ±0.05 K/year