Figure 3-12. Rtd Input Structure On The Ads1X48Evm; Table 3-4. Ads1X48Evm Terminal Block (J6) To Adc Connections - Texas Instruments ADS1x48EVM User Manual

www.ti.com
3.5.3 Connecting an RTD to J6 on the ADS1x48EVM
The RTD input connections on J6 are J6:3, J6:4, and J6:5, which correspond to the RTD_A, RTD_B, and
RTD_C nets, respectively. Additionally, terminal block J6 provides a pair of differential reference inputs, REFP1
and REFN1, which correspond to inputs J6:1 and J6:2, respectively. The RTD_A, RTD_B and REFP1, REFN1
input pairs have a differential filter with a cutoff frequency of 1.93 kHz. Additionally, each of these inputs has
a common-mode filter with a cutoff frequency of 38.63 kHz.
ADS1x48EVM, and Table 3-4
names, and the analog pins on the ADS1x48. Some nets may connect to multiple analog pins on the ADS1x48.

Table 3-4. ADS1x48EVM Terminal Block (J6) to ADC Connections

Connector Net Name
J6:1
J6:2
J6:3
J6:4
J6:5
J6:6
In Figure 3-12, resistor R11 is the reference resistor (R
to the ADS1x48 external reference inputs, as described in
the two IDACs integrated into the ADS1x48 flows through R
SBAU378A – SEPTEMBER 2021 – REVISED JANUARY 2022
Submit Document Feedback
describes the mapping between the terminal block connections, schematic net
REFP1
REFN1
JP3
REFP1
1
REFN1
2
RTD_A
3
4 RTD_B
RTD_C
5
6
J6
RTD_A
GND
RTD_B
JP4
RTD_C
JP5

Figure 3-12. RTD Input Structure on the ADS1x48EVM

ADS1x48 Input Connection
REFP1
REFN1
RTD_A
RTD_B
RTD_C
GND
Copyright © 2022 Texas Instruments Incorporated
Figure 3-12 shows the RTD input structure on the
JP6
R10
4.12k
C2
R11 1000pF
GND
4.02k
C6
R12
1000pF
4.12k
GND
R18
680
R20
4.12k
C11
1000pF
GND
C21
R28
1000pF
4.12k
R29
680
GND
REFP1
AIN1
REFN1
AIN0
AIN2
IEXC2
AIN3
IEXC1
IEXC1
n/a
) that is placed in series with the RTD and connected
REF
Table 3-4. An excitation current supplied by one of
and the RTD, creating a ratiometric relationship
REF
ADS1x48EVM Overview
AIN1
C5
0.01uF
AIN0
IEXC2
AIN2
C18
0.01uF
AIN3
IEXC1
Description
External reference input (positive)
Analog input 1
External reference input (negative)
Analog input 0
Analog input 2
Excitation current source #2
Analog input 3
Excitation current source #1
Excitation current source #1
Analog ground
ADS1x48EVM Evaluation Module 17