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, as well as validating and testing their design

implementation to confirm system functionality.

8.1 Application Information

The features of the ISOTMP35 make the device versatile for various high voltage temperature-sensing

applications. The ISOTMP35 can operated down to a 2.3-V supply with 9-µA current consumption. As a result,

the device is also well designed for battery applications where a number of these batteries may be stacked for

high voltage output.

8.1.1 Output Voltage Linearity

As illustrated in Figure 6-2, the ISOTMP35 device exhibit a linear output of 10 mV/°C. For temperature above

100°C, a small gain shift (TC) is present on the output (VOUT). When small shifts are expected, a piecewise

linear function provides the best accuracy and is used for the device accuracy specifications. Table 8-2 lists

the typical output voltages of the ISOTMP35 device across the full operating temperature range. The calculated

linear column represents 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 8-1. Use Equation 2 to calculate the

voltage output VOUT of the ISOTMP35:

VOUT = (TA - TINFL) ✕ TC + VOFFS

(2)

where

• VOUT is the 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 temperature coefficient or gain

• VOFFS is the voltage offset

Use Table 8-2 to calculate the ambient temperature (TA) for a given VOUT voltage output within a piecewise

voltage range (VRANGE). For applications where the accuracy enhancement above 100°C is not required, use the

first row of Table 8-1 for all voltages.

TA = (VOUT - VOFFS) ÷ TC + TINFL

(3)

Table 8-1. 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

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ISOTMP35

SNIS232 – OCTOBER 2023

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