TMP64 datasheet(9/28 Pages) TI

9 / 28 page

8 Detailed Description

8.1 Overview

The TMP64-Q1 silicon linear thermistor has a linear positive temperature coefficient (PTC) that results in a

uniform and consistent temperature coefficient resistance (TCR) across a wide operating temperature range. TI

uses a special silicon process where the the doping level and active region areas devices control the key

characteristics (the temperature coefficient resistance (TCR) and nominal resistance (R25)) . The device has an

active area and a substrate due to the polarized terminals. Connect the positive terminal to the highest voltage

potential. Connect the negative terminal to the lowest voltage potential.

Unlike an NTC, which is a purely resistive device, the TMP64-Q1 resistance is affected by the current across the

device and the resistance changes when the temperature changes. In a voltage divider circuit, it is

recommended to maintain the top resistor value at 47 kΩ. Changing the top resistor value or the V BIAS value

changes the resistance vs temperature table (R-T table) of the TMP64-Q1, and subsequently the polynomials as

described in Section 9.2.1.1. Consult Section 8.3.1 for more information.

TCR (ppm/°C) = (RT2 – RT1) / ((T2 – T1) × R(T2+T1)/2)

(1)

Below are the definitions of the key terms used throughout this document:

• ISNS: Current flowing through the TMP64-Q1.

• VSNS: Voltage across the two TMP64-Q1 terminals.

• IBias: Current supplied by the biasing circuit.

• VBias: Voltage supplied by the biasing circuit.

• VTemp: Output voltage that corresponds to the measured temperature. Note that this is different from VSns. In

the use case of a voltage divider circuit with the TMP64-Q1 in the high side, VTemp is taken across RBias.

8.2 Functional Block Diagram

RBias

VBias

VTemp

RTMP64

VTemp

RTMP64

IBias

Figure 8-1. Typical Implementation Circuits

www.ti.com

TMP64-Q1

SNIS220B – MARCH 2020 – REVISED NOVEMBER 2020

Submit Document Feedback

Product Folder Links: TMP64-Q1

TMP64 bảng dữ liệu(PDF) 9 Page - Texas Instruments