Evaluation Board Hardware; Hardware Link Options - Analog Devices EVAL-AD4857 User Manual

User Guide

EVALUATION BOARD HARDWARE

The AD4857 is a fully buffered, 8-channel simultaneous sampling,
16-bit 1 MSPS DAS with differential, wide common-mode range
inputs. The AD4857 has an on-chip low drift 4.096 V internal
voltage reference; however, it also optionally accepts an external
reference applied through the REFIO pin and provided to the
on-board LTC6655. The device operates from different power rails,
provided through on-board LDO regulators as described in
Supplies section. An option to connect external supplies exists and
is explained in Table 1.
Table 1. Jumper Details with the Factory Default Settings
Link Default Position
JODIFF to J7DIFF Not inserted
J0+ to J7+ Not inserted
J0− to J7− Not inserted
JV12V A
JSHIFT A
JVCC A
JVEE A
JVDDH A
JVDD A
JVDDL Not inserted
analog.com
Power
Function
Offset Calibration Jumper. Inserting the JODIFF to J7DIFF jumper link allows short circuiting the corresponding pair of inputs
to measure the AD4857 offset and/or to perform an offset calibration.
Analog Input to Ground Connection. Insert the J0+ to J7+ jumper link to connect to the AGND pin, the corresponding
positive analog input.
Analog Input to Ground Connection. Insert the J0− to J7− jumper link to connect to the AGND pin, the corresponding
negative analog input.
The JV12V link selects the power supply source for the EVAL-AD4857FMCZ evaluation board.
In Position A, the unregulated supply to the on-board LDO regulators is taken from the ZedBoard 12 V supply.
In Position B, the unregulated external supply to the on-board LDO regulators is taken from the V12V_EXT connector.
The JSHIFT link selects the power supply type for the AD4857.
In Position A, the V pin = +24 V, and the V
CC
In Position B, the V pin = +44 V, and the V
CC
If not inserted, the V pin = +24 V, and the V
CC
The JVCC link selects the V pin supply source.
CC
In Position A, the V pin is provided by the on board
CC
In Position B, the V pin is provided though VCC_EXT connector.
CC
The JVEE link selects the V pin supply source.
EE
In Position A, the V pin is provided by the on-board LT8330 DC/DC converter.
EE
In Position B, the V pin is provided though VEE_EXT connector.
EE
The JVDDH link selects the V pin supply source.
DDH
In Position A, the V pin is provided by the on board
DDH
In Position B, the V pin is provided though VDDH_EXT connector.
DDH
If not inserted, the V pin can be tied to the AGND pin by inserting an R40 resistor. To disable the internal LDO regulator,
DDH
tie the V pin to the GND pin. With the regulator is disabled, connect the V
DDH
1.71 V to 1.89 V through the JVDDL link.
The JVDD link selects the V pin supply source.
DD
In Position A, the V pin is provided by the on-board LT1761 5 V LDO regulator.
DD
In Position B, the V pin is provided though VDD_EXT connector.
DD
The JVDDL link selects the V pin supply source.
DDL
In Position A, the V pin is provided by the on-board LT1761 1.8 V LDO regulator. To use this configuration, tie the V
DDL
pin to ground through the JVDDH link.
In Position B, the V pin is provided though the VDDL_EXT connector. To use this configuration, tie the V
DDL
ground through the JVDDH link.
If not inserted, the internal LDO regulator is used for the JVDDH link to be in Position A or Position B.

HARDWARE LINK OPTIONS

Table 1 details the link option functions and the default power link
options. The EVAL-AD4857FMCZ can be powered from different
sources, as described in the Power Supplies
the power supply required for the EVAL-AD4857FMCZ comes from
the ZedBoard controller board. The power supply is regulated by
the on-board regulators that generate the required bipolar supplies.
pin = −24 V.
EE
pin = −4 V.
EE
pin = −4 V.
EE
LT8330 DC/DC converter.
LT1761 2.5 V LDO regulator.
DDL
EVAL-AD4857
section. By default,
pin to an external supply in the range of
pin to
DDH
Rev. A | 5 of 11
DDH