Power Supply Configurations; Analog Inputs; Reference Options - Analog Devices EVAL-AD7175-2SDZ User Manual

UG-AD7175-2
Table 3. Power Supply Configurations
Configuration
Single Supply (Regulated)
Single Supply (Unregulated)
Split Supply (Regulated)
Split Supply (Unregulated)
Only one configuration can be used at a time.
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POWER SUPPLY CONFIGURATIONS

Single Supply (Regulated)
There are two available power supply options for the single
supply (regulated) configuration.
•
An ac-to-dc adapter (included) connected to J5. Set LK2 to
Position B.
•
A bench top power supply connected to J3. Set LK2 to
Position A and ensure that AVSS = AGND = 0 V.
Set all other links and solder links to the default settings as
outlined in Table 1.
Single Supply (Unregulated)
To set up the board, use the following procedure:
1. Move SL2 and SL5 to Position A.
2. Connect the two terminals of J9 labeled AGND and AVSS.
3. Connect 0 V (GND) to J9 at the terminal labeled AGND.
4. Connect 5 V to J9 at the terminal labeled AVDD.
5. Connect 3.3 V to J9 at the terminal labeled IOVDD.
6. Connect the 7 V to 9 V input to J5.
Set all other links and solder links to the default settings as
outlined in Table 1.
Split Supply (Regulated)
To set up the board, use the following procedure:
1. Remove R49 to R51. These links connect AVSS to AGND.
2. Insert a zero ohm resistor for R85.
3. Set LK1 to Position B. This sets the input to the power
monitor circuitry to work with the lower AVDD1 supply of
2.5 V.
4. Connect a bench top power supply to J5 and set LK2 to
Position B.
5. Set LK1 to Position B. This sets the input to the power
monitor circuitry to work with the lower AVDD1 supply of
2.5 V.
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Input Voltage Range Description
7 V to 9 V The 7 V to 9 V input is regulated to 5 V for AVDD1/AVDD2 and 3.3 V for
IOVDD. This also powers the external 5 V reference. See the Single Supply
(Regulated) section in the Power Supply Configurations section.
7 V to 9 V, 5 V, and 3.3 V The input is unregulated and connects directly to AVDD1/AVDD2 and
IOVDD from J5. The 7 V to 9 V input powers the external 5 V reference. See the
Single Supply (Unregulated) section in the Power Supply Configurations section.
7 V to 9 V and −2.5 V The 7 V to 9 V input is regulated to 2.5 V for AVDD1/AVDD2 and 3.3 V for
IOVDD. The 7 V to 9 V input powers the external 5 V reference, and the −2.5 V
input is connected to AVSS directly (unregulated). See the Split Supply
(Regulated) section in the Power Supply Configurations section.
7 V to 9 V, ±2.5 V, and The input is unregulated and connects directly to AVDD1/AVDD2 and
IOVDD from J5. The 7 V to 9 V input powers the external 5 V reference. See the
3.3 V
Split Supply (Unregulated) section in the Power Supply Configurations section.
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EVAL-AD7175-2SDZ User Guide
Set all other links and solder links to the default settings as
outlined in Table 1.
Split Supply (Unregulated)
To set up the board, use the following procedure:
1. Move SL2, SL3 and SL5 to Position A.
2. Remove R49-R51.
3. Connect 0 V (GND) to J9 at the terminal labeled AGND.
4. Connect 2.5 V to J9 at the terminal labeled AVDD.
5. Connect −2.5 V to J9 at the terminal labeled AVSS.
6. Connect 3.3 V to J9 at the terminal labeled IOVDD.
7. Connect 7 V to 9 V to J5.
8. Set LK1 to Position B. This sets the input to the power monitor
circuitry to work with the lower AVDD1 supply of 2.5 V.
Set all other links and solder links set to the default settings as
outlined in Table 1.

ANALOG INPUTS

The EVAL-AD7175-2SDZ primary analog inputs can be applied
in two separate ways.
•
J6 connector on the left side of the board
•
A0 to A4 SMB/SMA footprints on the evaluation board
The analog inputs route directly to the associated analog input
pins on the AD7175-2, provided that the LK5 to LK9 links (on-
board noise test) are removed. The
software is set up to analyze dc inputs to the ADC. The
AD7175-2 input buffers work for dc input signals.

REFERENCE OPTIONS

The EVAL-AD7175-2SDZ includes an external 5 V reference,
the ADR445. The AD7175-2
The default operation is to use the external reference input,
which is set to accept the 5 V ADR445
EVAL-AD7175-2SDZ
includes an internal 2.5 V reference.
on the evaluation board.