Voltage Reference - Texas Instruments ADS1282V2EVM-PDK User Manual

Hardware
2.4 Analog Input 2 Amplifier
Figure 2-4 shows the fully differential amplifier circuit (THS4551) that drives ADC input channel 2. This
amplifier circuit provides flexibility for different input configurations, including single-ended and differential
inputs. Additionally, the circuit enables signals with different common-mode voltages to easily interface with
the ADS1282.
+AIN2
3
2
1
J5
-AIN2

2.5 Voltage Reference

Figure 2-5 shows the REF6050
through the 0Ω resistors R12 and R18. The REF6050 integrates a low output impedance buffer necessary for
precision ADCs to maintain a steady reference voltage during the conversion process.
Use an external reference source in place of the REF6050 by removing R12 and R18, and installing header J4.
The positive terminal of the voltage reference connects to header J4 pin 1, and the negative terminal to header
J4 pin 2. The pins of header J4 can also be used as test points for the onboard REF6050. Use resistors R9 and
R13 (not shown) as optional filter resistors when using an external voltage reference. Remove resistor R11 to
disable the voltage output of the REF6050 voltage reference.
Remove R11 to disable voltage
reference
6 ADS1282EVM-PDK Evaluation Module
7
R29
8
1.00k
Vocm
2
R32
DNP
1
20.0k
Vocm
R35
GND DNP
20.0k
R36
1.00k
Figure 2-4. Analog Input 2 Amplifier
voltage reference circuit. By default, the REF6050 connects to the ADS1282
AVDD(5.3)
C8
1µF
AVSS U2
1
VIN
R11
0
2
EN
3
SS
4
FILT
R21 R22 REF6050IDGKR
C14
10.0k 120k
1µF
AVSS AVSS AVSS
Figure 2-5. Onboard Voltage Reference
Copyright © 2024 Texas Instruments Incorporated
R28
1.00k
AVDD(5.3)
C15
0.1uF
AVSS
U3
THS4551IDGKR
R30
5
V+
15
VOCM
4
V-
R33
15
AVSS
R37
1.00k
5
OUT_S
6
OUT_F
7
GND_F
8
GND_S
AVSS
R31
AINN2
10
C18
0.01 µF
R34
AINP2
10
Remove R12 and R18 to disconnect
REF6050 reference and then install
J4 to provide an external reference
J4
EXT_REF
Vref
DNP
R12 0
R15
0.22
C11
0.01uF
C13 R18
22µF 0
AVSS
SBAU431 – JULY 2024
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To R9
To R13