Analog Devices EVAL-ADAQ7980SDZ, Руководство пользователя

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UG-1060 EVAL-ADAQ7980SDZ User Guide
Rev. 0 | Page 8 of 30
EVALUATION BOARD HARDWARE
Figure 16. EVAL-ADAQ7980SDZ Simplified Block Diagram
HARDWARE OVERVIEW
Figure 16 shows a simplified block diagram of the EVAL-
ADAQ7980SDZ . The evaluation board features the ADAQ7980
and peripheral circuitry that evaluates the device. This section
gives an overview of the
ADAQ7980 operation and describes
how the operation parameters can be configured on the EVAL-
ADAQ7980SDZ hardware.
The EVAL-ADAQ7980SDZ allows a variety of configuration
options for many of the major operation nodes of the ADAQ7980 .
The evaluation board provides two on-board reference options
(5 V and 3.3 V), pads to set multiple configurations for the
ADC driver, and various power supply options. The following
sections describe these options in detail.
Figure 28 to Figure 32 show the evaluation board schematics. The
evaluation board is a flexible design that enables the user to adjust
compensation components and operate the evaluation board from
an adjustable bench top power supply.
REFERENCE
The reference setting of the ADAQ7980 (the voltage set at the REF
input) determines the full-scale input range at the integrated ADC
inputs which determines the output range of the integrated ADC
driver (the range of the AMP_OUT pin). For example, if using a
5 V reference, then the
ADAQ7980 can convert signals on the
AMP_OUT pin between 0 V and 5 V before the signal overranges.
The REF pin of the
ADAQ7980 is the input to the integrated
reference buffer. The REF_OUT pin is the output of the reference
buffer and the reference node utilized by the integrated ADC.
When utilizing the reference buffer, drive the REF pin to the
desired reference voltage for the system. See the
ADAQ7980 /
ADAQ7988 data sheet for more information regarding reference
voltage operation.
The
EVAL-ADAQ7980SDZ has two reference devices installed:
the ADR4550BRZ supplying 5 V and the ADR3433ARJZ supplying
3.3 V. Either of these references can be routed to the REF pin of the
ADAQ7980 by means of jumpers and links on the evaluation
board.
In addition to the on-board
ADR4550BRZ and ADR3433ARJZ
references, the EVAL-ADAQ7980SDZ provides the option to
supply the reference externally through Pin 5 on the
P6 terminal block.
VIN+
EVAL-ADAQ7980SDZ EVALUATION BOARD
ADC
REF
GND
VDD
IN+
IN–
VIO
SDI
SCK
SDO
CNV
20Ω
V+
V–
1.8nF
10µF
LDO
2.2µF
REF_OUT LDO_OUT
PD_REF
AMP_OUT
PD_AMP
PD_LDO
+7.5V/+5.0V
+7.5V/+5.0V
+3.3V
–2.5V/0V
ADCN
ADAQ7980
PD_LDO
PD_AMP
PD_REF
POWER SUPPLY CIRCUITRY
ADP7118, ADP2370, ADP7182
+7.5V +5.0V –2.5V +3.3V
+9V
DC
PLUG
REFERENCE CIRCUITRY
ADR4550/ADR3433
+5.0V/+3.3V
+7.5V/+5.0V
VCM
ADSP-BF527
EVAL-SDP-CB1Z
+5V
USB
15065-
1
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