Adc Connections And Decoupling - Texas Instruments ADS1263EVM-PDK User Manual

Analog Interface

3.2 ADC Connections and Decoupling

Figure 3-10 shows all ADC connections. Each power-supply and reference connection has a 1-µF decoupling
capacitor. Place these capacitors as close as possible to the ADC pins and make sure each component has a
low-impedance connection to the GND plane.
Each ADC digital pin has a 49.9-Ω series resistor in series with the trace. These resistors smooth the edges
of the digital signals to minimize overshoot and ringing. A resistor is most important on the serial clock (SCLK)
trace because the SCLK signal can toggle as quickly as 40 MHz. Resistors on the other pins are not strictly
required, though these components can be included in the final design to improve digital signal integrity.
AVDD
DVDD
C2
1uF
A0
C1
A1
1uF
GND A2
A3
A4
GND
A5
A6
A7
A8
A9
AINCOM
REFOUT
C20
1uF
GND
GND
Figure 3-10. ADS1263EVM ADC Power-Supply Decoupling and Analog and Digital Connections
14 ADS1263EVM-PDK Evaluation Module
U1
6
AVDD START
RESET/PWDN
19
DVDD
21
AIN0 DOUT/DRDY
22
AIN1
23
AIN2
24
AIN3
25
AIN4 XTAL1/CLKIN
26
AIN5
27
AIN6 XTAL2
28
AIN7
1
AIN8
2
AIN9
3
AINCOM
8
REFOUT
17
BYPASS
C3
ADS1263IPWR
1uF
Copyright © 2023 Texas Instruments Incorporated
9
20
11
SCLK
12
DIN
13
14
DRDY
10
CS
CLKIN
15
16
4
CAPP
C14
4700pF
5
CAPN
7
AVSS
18
DGND
GND
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R40 49.9 ADC.START
R15 49.9 ADC.RESET/PWDN
R16 49.9 ADC.SCLK
R17 49.9 ADC.DIN
R18 49.9 ADC.DOUT/DRDY
R19 49.9 ADC.DRDY
R20 49.9 ADC.CS
SBAU206B – APRIL 2015 – REVISED MAY 2023
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