AN3108 datasheet(6/44 Pages) STMICROELECTRONICS

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STLM75 temperature sensor

AN3108

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Doc ID 16793 Rev 1

STLM75 temperature sensor

2.1

Sensor introduction

The STLM75 is a high-precision digital CMOS temperature sensor IC with a sigma-delta

temperature-to-digital converter and an I2C-compatible serial digital interface. It is targeted

at general applications such as personal computers, system thermal management,

electronics equipment, and industrial controllers, and is packaged in the industry standard

8-lead TSSOP and SO8 packages. The device contains a band-gap temperature sensor

and 9-bit ADC which monitor and digitize the temperature to a resolution up to 0.5 °C. The

STLM75 is typically accurate to ±3°C - max over the full temperature measurement range of

-55 °C to 125 °C with ±2 °C accuracy in the -25 °C to + 100 °C range (max). The STLM75 is

factory-calibrated and requires no external components to measure temperature.

Refer to the STLM75 (Digital temperature sensor and thermal watchdog) datasheet for more

information.

2.2

Interfacing the sensor with the microcontroller

The STLM75 has a simple 2-wire I2C-compatible digital serial interface which allows the

user to access the data in the temperature register at any time. It communicates via the

serial interface with a master controller which operates at speeds up to 400 kHz. Three pins

(A0, A1, and A2) are available for address selection, and enable the user to connect up to 8

devices on the same bus without address conflicts. In addition, the serial interface gives the

user easy access to all STLM75 registers to customize the operation of the device.

Figure 2 shows how the SMT32F10xxx microcontroller (master device) must be connected

to the STLM75 device.

Refer to the STLM75 datasheet for more information.

Figure 1.

Logic diagram

Note:

SDA and OS/INT are open drain.

AN3108 Datasheet(PDF) 6 Page - STMicroelectronics