Texas Instruments ADS1285EVM-PDK, User Manual, Page: 10 / 40

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.
Table 4-2 describes the digital
header pins.
Table 4-2. Digital Header Pins
Signal Name Digital Header Pin
~RESET J9[1]
~PWDN J9[3]
SYNC J9[5]
DIN_PHI J9[7]
GPIO1 J9[9]
GPIO0 J9[11]
~CS_ADC J9[13]
SCLK_PHI J9[15]
~DRDY J9[17]
ADC_CLK J9[19]
DOUT J9[21]
~RST/PWDN_DAC J9[23]
SYNC_DAC J9[25]
SW/TD_DAC J9[27]
~CS_DAC J9[29]
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 describe the supply generation and programmable configurations, respectively.
AVDD2
1µF
C15
5.5V
GND
GND
GND
AVDD1 supply for ADS1285
AVDD2 supply for ADS1285
AVDD supply for DAC1282
AVDD2 is referenced to the ADC's AGND
10uF
C11
GND
AVDD1
1µF
C13
5.5V
10uF
C9
AVSS
AVSS
AVSS
AVSS
AVSS+5V
1µF
C16
5.5V
10uF
C14
AVSS
AVSS
AVSS
AVSS
Do NOT modify!
The DAC1282 requires a 5V analog supply
Default: 5V
Default: 3V
10uF
C8
10uF
C10
10uF
C12
NOTE: If you con fi gure AVDD1 for 3.3V, replace REF6241 with a REF6225!
OUT
1
NC
2
SENSE/FB
3
6P4V2
4
6P4V1
5
3P2V
6
GND
7
1P6V
8
0P8V
9
0P4V
10
0P2V
11
0P1V
12
EN
13
NR
14
IN
15
IN
16
NC
17
NC
18
NC
19
OUT
20
PAD
21
TPS7A4701QRGWRQ1
U2
OUT
1
NC
2
SENSE/FB
3
6P4V2
4
6P4V1
5
3P2V
6
GND
7
1P6V
8
0P8V
9
0P4V
10
0P2V
11
0P1V
12
EN
13
NR
14
IN
15
IN
16
NC
17
NC
18
NC
19
OUT
20
PAD
21
TPS7A4701QRGWRQ1
U3
OUT
1
NC
2
SENSE/FB
3
6P4V2
4
6P4V1
5
3P2V
6
GND
7
1P6V
8
0P8V
9
0P4V
10
0P2V
11
0P1V
12
EN
13
NR
14
IN
15
IN
16
NC
17
NC
18
NC
19
OUT
20
PAD
21
TPS7A4701QRGWRQ1
U4
0
R8
0
R9
0
R10
0
R11
0
R12
0
R13
0
R14
0
R15
0
R16
0
R17
0
R18
0
R19
0
R20
0
R21
0
R22
0
R23
0
R24
0
R25
1
3
N
C
2
D1
PLVA653A,215
TP1
AVSS+5V
Figure 5-1. ADS1285EVM-PDK AVDD1, AVDD2, and AVSS+5V Supply Generation (Schematic)
Digital Interface www.ti.com
10 ADS1285EVM-PDK Evaluation Module SBAU394A – APRIL 2022 – REVISED SEPTEMBER 2022
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