Evaluation Board Hardware; Power Supplies; Link Options - Analog Devices EVAL-AD7766 Preliminary Technical Data

Preliminary Technical Data

EVALUATION BOARD HARDWARE

POWER SUPPLIES

When using this evaluation board with the CED, incorporating the use of the ADA4841-1 amplifiers (maximum supply spread of 12V) a
+7.5V and -2.5V supply must be provided at the connector marked J12. When using J12 as the source connection to power the
AD7766/67 board then links LK1 and LK2 must be placed in position B.
The 7.5V supply to J12 is then routed through ADP3330 LDO to create the +2.5V supply to power AVDD1 (pin 1), DVDD (pin 8) and
VDRIVE (pin 9). The 7.5V is also supplied to the reference (ADR425 or ADR445) which creates the 5V reference signal applied to pin 2
of the converter.
An extensive ground plane are used on this board to minimize the effect of high frequency noise interference. There in one ground plane
to which all supplies are decoupled to.

LINK OPTIONS

There are 3 link options that must be set for the required operating setup before using the evaluation board. The functions of the options
are outlined in Table 1. These options are initially setup so that the user supplies +7.5V and -2.5V to the V+ and V- terminals of J12 in
order to comply with the voltage regulations of the ADA4841-1 amplifiers (U2 & U3) as seen in the default value listed. If the user wishes
to substitute the AD8021 amplifier for ADA4841 then the CED board can be used to supply the required ±12V to the evaluation board.
See Table 1 for further details.
Table 1. Link Option Functions
Link Position Function
No.
LK1 This link option is used to select the source of the V+ voltage which is used to power the evaluation board.
When using the ADA4841 amplifiers the evaluation board must be supplied with a +7.5V at the V+
terminal at (J12).
A V+ is supplied from the CED through the 96-way connector. Do not use this option when using the
ADA4841-1 amplifiers. In the case of use of the AD8021 amplifers LK1 may be set to A, allowing the
AD8021 to be powered off the +12V supplied by the CED board through the 96-way connector.
B In Position B, V
operate the AD7766/67 evaluation board using the ADA4841-1 devices.
LK2 This link option is used to select the source of the V- voltage which is used to power the evaluation board.
When using the ADA4841 amplifiers the evaluation board must be supplied with a -2.5V at the V- terminal
at (J12).
A V- is supplied from the CED through the 96-way connector. Do not use this option when using the
ADA4841-1 amplifiers. In the case of use of the AD8021 amplifers LK2 may be set to A, allowing the
AD8021 to be powered off the -12V supplied by the CED board through the 96-way connector.
B In Position B, V
operate the AD7766/67 evaluation board using the ADA4841-1 devices.
LK3 This link option selects the source of the voltage input to the precision reference (either ADR445 or
ADR425)
A
The V+ voltage supplied to the reference is generated by the external supply at J12 or from CED
depending on the settings used for LK1 and LK2.
B Allows the user to apply an external supply directly to the reference.
is supplied from an external source via the power connector, J12. Set LK1 to B to
DD
is supplied from an external source via the power connector, J12. Set LK2 to B to
DD
Rev. PrA | Page 3 of 20
EVAL-AD7766/AD7767
Default
B
B
A