EVAL-AD7482CB Datasheet, PDF (3/20 Pages) Analog Devices – Evaluation Board for 3 MSPS, 12-Bit SAR ADC

EVAL-AD7482CB
EVALUATION BOARD HARDWARE
OPERATING THE AD7482 EVALUATION BOARD
Power Supplies
When using this evaluation board with the EVAL-CONTROL
BRD2, all supplies are provided from the controller board
through the 96-way connector.
When using the board as a standalone unit, external supplies
must be provided. This evaluation board has nine power supply
inputs: AVDD, AGND, +12 V, −12 V, AGND, DVDD, DGND,
VDRIVE, and DGND. If the evaluation board is used in stand-
alone mode, a +5 V supply must be connected to both the AVDD
and DVDD inputs. The +12 V and −12 V supplies are required
for the op amps. The VDRIVE input can be connected to a supply
from +2.7 V to +5 V, allowing the evaluation board to be con-
nected to both +3 V and +5 V systems. The supplies are decoupled
to the ground plane with 10 μF tantalum and 0.1 μF multilayer
ceramic capacitors at the point where they enter the board.
Noise on the supplies is further reduced with the use of EMC
filters and ferrite beads. The supply pins of all the op amps
and the reference are also decoupled with 10 μF tantalum and
0.1 μF ceramic capacitors as are the VDD pins of the AD7482.
This evaluation board consists of four layers. One of these layers
is used as a dedicated ground plane, which allows for good
decoupling and shielding.
LINK OPTIONS
There are 25 link options which must be set for the required operating setup before using the evaluation board. The functions of the
options are outlined in Table 1. There is no Link 25.
Table 1.
Link No.
LK1
LK2
LK3
LK4, LK5
LK6
LK7
LK8
LK9
LK10
LK11
LK12
Function
Selects the source of CONVST input.
In Position A, CONVST is sourced from the external connector, J9.
In Position B, CONVST is connected to the 96-way connector.
Selects the source for the bias up voltage.
In Position A, it is connected to the reference voltage (divided down by R6 and R8).
In Position B, it is connected to AVDD.
In Position C, it is connected to the external connector, J10.
Used to short out the 1 kΩ series input resistor on the analog input.
Used to select which op amp is utilized in the analog input bias up circuitry. Both these links must be set to the same
position.
Position A selects the AD829.
Position B selects the AD8022.
Used to put the AD7482 into standby mode.
In Position A, the standby pin is connected to DVDD, putting the part in standby mode.
In Position B, the standby pin is connected to GND for normal operation.
Used to put the AD7482 into nap mode.
In Position A, the NAP pin is connected to DVDD putting the part in nap mode.
In Position B, the NAP pin is connected to GND for normal operation.
Selects whether the CLIP input is tied high or low.
Position A ties the CLIP pin to DVDD.
Position B ties the CLIP pin to GND. See the AD7482 data sheet for further details.
Selects whether the MODE1 input is tied high or low.
Position A ties the MODE 1 pin to DVDD.
Position B ties the MODE 1 pin to GND. See the AD7482 data sheet for further details.
Selects whether the MODE2 input is tied high or low.
Position A ties the MODE2 pin to DVDD.
Position B ties the MODE2 pin to GND. See the AD7482 data sheet for further details.
Configures the AD7482 for use with an internal or external reference. With this link in position, the part is configured for use
with an external +2.5 V reference.
Selects the source for the VDRIVE voltage.
In Position A, VDRIVE is connected to DVDD.
In Position B, VDRIVE is taken from the external connector, J5.
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