GND

VOUT

VDD

Thermal Diodes

8

TMP235, TMP236

SBOS857E – SEPTEMBER 2017 – REVISED MAY 2019

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7 Detailed Description

7.1 Overview

The TMP23x devices are a family of linear analog temperature sensors with an output voltage proportional to

temperature. These temperature sensors have an accuracy from 0°C to 70°C of ±1.25°C (TMP23xA2) and ±2°C

(TMP23xA4). The TMP235 device provides a positive slope output of 10 mV/°C over the full –40°C to +150°C

temperature range and a supply range from 2.3 V to 5.5 V. The higher gain TMP236 sensor provides a positive

slope output of 19.5 mV/°C from –10°C to +125°C and a supply range from 3.1 V to 5.5 V. A class-AB output

driver provides a maximum output of 500 µA to drive capacitive loads up to 1000 pF.

7.2 Functional Block Diagram

7.3 Feature Description

As shown in Figure 3, the TMP23x devices are linear. A small VOUT gain shift, however, is present at

temperatures above 100°C. When small shifts are expected, a piecewise linear function provides the best

accuracy and is used for the device accuracy specifications (see Specifications). Typical output voltages of the

TMP23x devices across the full operating temperature range are listed in Table 3 and Table 4. The ideal linear

columns represent the ideal linear VOUT output response with respect to temperature, while the piecewise linear

columns indicate the small voltage shift at elevated temperatures.

The piecewise linear function uses three temperature ranges listed in Table 1 and Table 2. In equation form, the

voltage output VOUT of the TMP23x is calculated by Equation 1:

VOUT = (TA – TINFL) × TC + VOFFS

where

•

VOUT is the TMP23x voltage output for a given temperature

•

TA is the ambient temperature in °C

•

TINFL is the temperature inflection point for a piecewise segment in °C

•

TC is the TMP23x temperature coefficient or gain

•

VOFFS is the TMP23x voltage offset

(1)

Therefore, the TA temperature for a given VOUT voltage output within a piecewise voltage range (VRANGE) is

calculated in Equation 2. For applications where the accuracy enhancement above 100°C is not required, use the

first row of Table 1 and Table 2 for all voltages.

TA = (VOUT – VOFFS ) / TC + TINFL

(2)

Table 1. TMP235 Piecewise Linear Function Summary

TA RANGE

(°C)

VRANGE (mV)

TINFL (°C)

TC (mV/°C)

VOFFS (mV)

–40 to +100

< 1500

0

10

500

100 to 125

1500 to 1752.5

100

10.1

1500

125 to 150

> 1752.5

125

10.6

1752.5