TMP108

1.4 V to 3.6 V

GND

A2

A1

C2

B2

B1

A0

C1

V+

SDA

SCL

ALERT

GND

V+

100 kW

Two-Wire

Controller

17

TMP108

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SBOS663A – APRIL 2013 – REVISED SEPTEMBER 2019

Product Folder Links: TMP108

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8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

The TMP108 is used to measure the temperature of the board location where the device is mounted. The

programmable address options allow up to four locations on the board to be monitored with a single serial bus.

8.2 Typical Application

Figure 15. Typical Application Circuit

8.2.1 Design Requirements

The TMP108 only requires pullup resistors on SCL and SDA, but TI also recommends to use a 0.01-μF bypass

capacitor as shown in Figure 15. There is an internal 100-kΩ pullup resistor connected to supply on the ALERT

pin. If required, use an external resistor of smaller value on the ALERT pin for a stronger pullup to V+. The SCL

and SDA lines can be pulled up to a supply that is equal to or higher than V+ through the pullup resistors. To

configure one of four different addresses on the bus, connect A0 to either V+, GND, SCL, or SDA. If A0 is

connected to SCL or SDA, make their pullup supply equal to V+.

8.2.2 Detailed Design Procedure

The TMP108 devices must be placed in close proximity to the heat source that must be monitored, with a proper

layout for good thermal coupling. This placement ensures that temperature changes are captured within the

shortest possible time interval. To maintain accuracy in applications that require air or surface temperature

measurement, take care to isolate the package and leads from PCB heat sources.