SCL

SDA

THERM

D+

D-

V+

GND

ALERT/THERM2

6 x I

16 x I

Internal

BJT

ADC

Control Logic

TMP451-Q1

Register Bank

Serial Interface

Oscillator

Voltage Regulator

I

TMP451-Q1

SLOS877 – OCTOBER 2014

www.ti.com

7 Detailed Description

7.1 Overview

The TMP451-Q1 device is a digital temperature sensor that combines a local temperature measurement channel

and a remote-junction temperature measurement channel in a single DFN-8 package. The device is two-wire-

and SMBus-interface compatible, and is specified over a temperature range of –40°C to 125°C. The TMP451-Q1

device also contains multiple registers for programming and holding configuration settings, temperature limits,

and temperature measurement results.

7.2 Functional Block Diagram

7.3 Feature Description

7.3.1 Temperature Measurement Data

The local and remote temperature sensors have a resolution of 12 bits (0.0625°C). Temperature data that result

from conversions within the default measurement range are represented in binary form, as shown in the

Standard Binary column of Table 1. Any temperature below 0°C results in a data value of 0 (00h). Likewise,

temperatures above 127°C result in a value of 127 (7Fh). The device can be set to measure over an extended

temperature range by changing bit 2 (RANGE) of configuration register from low to high. The change in

measurement range and data format from standard binary to extended binary occurs at the next temperature

conversion. For data captured in the extended temperature range configuration, an offset of 64 (40h) is added to

the standard binary value, as shown in the EXTENDED BINARY column of Table 1. This configuration allows

measurement of temperatures as low as –64°C, and as high as 191°C; however, most temperature-sensing

diodes only measure with the range of –55°C to 150°C. Additionally, the TMP451-Q1 is specified only for

ambient temperatures ranging from –40°C to 125°C; parameters in the Absolute Maximum Ratings table must be

observed.

8

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