Datasheet

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RTDs and Thermistors
ADS1232
16
9
10
14
11
13
12
15
20
19
24
23
22
4
3
21
8
7
REFP
CAP
CAP
AINP2
AINP1
AINN2
AINN1
REFN
GAIN0
AVDD DVDD
AGND DGND
DRDY/DOUT
SCLK
PDWN
XTAL2
CLKIN/XTAL1
SPEED
A0
TEMP
0.1 Fm
0.1 Fm
5V 3V
GAIN1
17 2,5,6
18 1
MSP430x4xx
orOther
Microprocessor
VDD
GND
Gain=128
R
1
33kW
R
2
33kW
R
L
R
L
R
L
RTD
NOTE:R isleadresistance.
L
ADS1232
ADS1234
SBAS350F – JUNE 2005 – REVISED FEBRUARY 2008
By using both differential channels of the ADS1232,
the temperature change in lead resistance, R
L
, can
Figure 45 shows a typical schematic for a style 2
be eliminated. This condition is accomplished by
(three-wire) RTD application. R
1
and R
2
are used to
using the following formula:
excite the RTD as well as establish the
common-mode voltage of the ADS1232 PGA.
(AINP1 – AINN1) – 2(AINP2 – AINN2).
Figure 45. Style 2 (Three-Wire) RTD Schematic
Copyright © 2005 – 2008, Texas Instruments Incorporated 27
Product Folder Link(s): ADS1232 ADS1234