Diode

Temp

Sensor

DS

ADC

OSC

Control

Logic

Serial

Interface

Config

and Temp

Register

TMP108

V+

A1

C1

A2

C2

ALERT

GND

A0

B1

B2

SCL

SDA

9

TMP108

www.ti.com

SBOS663A – APRIL 2013 – REVISED SEPTEMBER 2019

Product Folder Links: TMP108

Submit Documentation Feedback

Copyright © 2013–2019, Texas Instruments Incorporated

7 Detailed Description

7.1 Overview

The TMP108 is a digital temperature sensor optimal for thermal management and thermal protection

applications. The TMP108 is two-wire and SMBus Interface compatible, and is specified over a temperature

range of –40°C to +125°C.

The TMP108 temperature sensor is the chip itself. The solder bumps provide the primary thermal path as a result

of the lower thermal resistance of metal. The temperature sensor result is equivalent to the local temperature of

the printed-circuit board (PCB) on which the sensor is mounted.

7.2 Functional Block Diagram

7.3 Feature Description

7.3.1 Serial Interface

The TMP108 operates as a slave device only on the two-wire bus and SMBus. Connections to the bus are made

using the open-drain I/O lines, SDA and SCL. The SDA and SCL pins feature integrated spike-suppression filters

and Schmitt triggers to minimize the effects of input spikes and bus noise. The TMP108 supports the

transmission protocol for both fast (1 kHz to 400 kHz) and high-speed (1 kHz to 3.4 MHz) modes. All data bytes

are transmitted MSB first.

7.3.2 Serial Bus Address

To communicate with the TMP108, the master must first communicate with slave devices using a slave address

byte. The slave address byte consists of seven address bits, and a direction bit indicating the intent of executing

either a read or write operation. The TMP108 features an address pin that allows up to four devices to be

addressed on a single bus. The TMP108 latches the status of the address pin at the start of a communication.

Table 2 describes the pin logic levels and the corresponding address values. Other values for the fixed address

bits are available by request.

Table 2. Address Pin and Slave Addresses

DEVICE TWO-WIRE ADDRESS

A0 PIN CONNECTION

TMP108

1001000

Ground

1001001

V+

1001010

SDA

1001011

SCL