Digital Header; Power Supplies; Figure 5-1. Ads1285Evm-Pdk Avdd1, Avdd2, And Avss+5V Supply Generation (Schematic); Table 4-2. Digital Header Pins - Texas Instruments ADS1285EVM-PDK User Manual

Digital Interface

4.2 Digital Header

In addition to the PHI, the EVM has a header connected to the digital lines that can be used to connect a
logic analyzer or oscilloscope. This placement allows for easy access to the digital communications. Header J9
is connected to the digital lines between the ADS1285 and the PHI connector.
header pins.

5 Power Supplies

The PHI provides multiple power-supply options for the EVM, derived from the USB supply of the computer that
is routed to the 5.5-V net on the ADS1285EVM-PDK on the board.
The EEPROM on the ADS1285EVM-PDK uses a 3.3-V power supply, ID_PWR, generated directly by the PHI.
The 3.3-V supply to the digital section of the ADC (3V3_IOVDD) is provided directly by a separate LDO on the
PHI.
Figure 5-1 and Table 5-1
AVDD1 supply for ADS1285
U2
5.5V
15 1
Default: 5V
IN OUT
16 20
IN OUT
C8
10uF 13 3
EN SENSE/FB
AVSS
14
NR
4
6P4V2
5 19
6P4V1 NC
6 18
3P2V NC
8 17 C13
1P6V NC
1µF
9 2
0P8V NC
10
0P4V
11 7
0P2V GND
12 21
0P1V PAD
R8 R9 R10 R11 R12
R13
0 0 0 0 0
0 TPS7A4701QRGWRQ1
AVSS
AVSS
NOTE: If you configure AVDD1 for 3.3V, replace REF6241 with a REF6225!

Figure 5-1. ADS1285EVM-PDK AVDD1, AVDD2, and AVSS+5V Supply Generation (Schematic)

10 ADS1285EVM-PDK Evaluation Module

Table 4-2. Digital Header Pins

Signal Name
~RESET
~PWDN
SYNC
DIN_PHI
GPIO1
GPIO0
~CS_ADC
SCLK_PHI
~DRDY
ADC_CLK
DOUT
~RST/PWDN_DAC
SYNC_DAC
SW/TD_DAC
~CS_DAC
describe the supply generation and programmable configurations, respectively.
AVDD2 supply for ADS1285
AVDD1
5.5V
C9 15
10uF 16
C10
AVSS 10uF
13
GND
D1
PLVA653A,215 4
5
6
8
9
10
11
12
R14 R15 R16 R17 R18
R19
0 0 0 0 0
0
GND
Copyright © 2022 Texas Instruments Incorporated
Digital Header Pin
J9[1]
J9[3]
J9[5]
J9[7]
J9[9]
J9[11]
J9[13]
J9[15]
J9[17]
J9[19]
J9[21]
J9[23]
J9[25]
J9[27]
J9[29]
U3
AVDD2
1
Default: 3V
IN OUT
20
IN OUT
C11
3
EN SENSE/FB
10uF
14
NR
GND
6P4V2
19
6P4V1 NC
18
3P2V NC
17 C15
1P6V NC
1µF
2
0P8V NC
0P4V
7
0P2V GND
21
0P1V PAD
TPS7A4701QRGWRQ1
AVDD2 is referenced to the ADC's AGND
GND
Do NOT modify!
The DAC1282 requires a 5V analog supply
SBAU394A – APRIL 2022 – REVISED SEPTEMBER 2022
Table 4-2 describes the digital
AVDD supply for DAC1282
U4
5.5V
15 1
IN OUT
16 20
IN OUT
C12
10uF 13 3
EN SENSE/FB
AVSS
14
NR
4
6P4V2
5 19
6P4V1 NC
6 18
3P2V NC
8 17
1P6V NC
9 2
0P8V NC
10
0P4V
11 7
0P2V GND
12 21
0P1V PAD
R20 R21 R22 R23 R24
R25
0 0 0 0 0
0 TPS7A4701QRGWRQ1
AVSS
AVSS
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AVSS+5V
TP1
AVSS+5V
C14
10uF
AVSS
C16
1µF