Datasheet

EVAL-AD5665R
Rev. 0 | Page 3 of 3
EVALUATION BOARD HARDWARE
POWER SUPPLIES
To power the EVAL-AD5665REBZ, supply the voltage (2.7 V to
5.5 V) between the AVDD and AGND inputs for the analog
supply of the AD5665R (J6). Alternatively, placing Link 6 in
Position B powers the analog circuitry from the USB port
(default setting). This powers all devices with 3.3 V supply.
Both AGND and DGND inputs are provided on the board. The
AGND and DGND planes are connected at one location close
to the AD5665R. To avoid ground loop problems, it is recom-
mended not to connect AGND and DGND elsewhere in the
system.
Each supply is decoupled to the relevant ground plane with
10 μF and 0.1 μF capacitors. Each device supply pin is also
decoupled with a 10 μF and 0.1 μF capacitor pair to the relevant
ground plane.
LINK OPTIONS
A number of link and switch options on the evaluation board
should be set for the required operating setup before using the
board. The functions of these link options are described in
detail in Table 2. The default setup is for control by the PC via
the USB port and for evaluating the part in standard/fast mode
with an external 3 V reference, the AD780. The default link
options are listed in Table 1.
Table 1. Link Options Setup for PC Control (Default)
Link No. Option
LK1 to LK4 Inserted
LK5 B
LK6 B
LK7 A
LK8 A
LK9 A
LK10 Removed
LK11 B
LK12 B
LK13 A
LK14 A
LK15 A
LK16 Inserted
Table 2. Link Functions
Link No. Function
LK1 to LK4
These links connect the V
OUT
A to V
OUT
D pins of the AD5665R to the input pins of ADG728 demultiplexer to monitor the
DAC output value using the on-board AD7992 ADC.
LK5 This link selects the AVDD power supply source for the analog circuitry.
Position A selects J6 as the AVDD analog circuitry power supply source.
Position B selects the 3.3 V power supply source as the AVDD analog circuitry power supply source (see LK6).
LK6 This link selects the DVDD supply source for the digital circuitry.
Position A selects J7 as the digital circuitry power supply source.
Position B selects the 3.3 V USB as the digital circuitry power supply source.
LK7
This link selects whether the AD5665R evaluation board is controlled by the PC via the USB port or by an external source
via the SMB connectors J1 to J12.
Position A selects control by the PC via the USB port.
Position B selects control by an external source via the SMB connectors J1 to J4.
LK8 This link sets the RESET pin on the ADG728.
Position A allows normal operation of the switch.
Position B resets the switch.
LK9 This link selects the AVDD power supply source for the AD780 reference.
Position A selects J6-3 as the AD780 power supply source.
Position B selects the 5 V USB supply voltage as the AD780 power supply source.
LK10
This link connects a 0.1 μF capacitor to AGND on the V
REFOUT
pin. It is recommended to connect this when using the
internal reference.
LK11 This link selects the reference source.
Position A selects the internal reference as the reference source. The part must be written to via software to turn on the
internal reference.
Position B selects the on-board AD780 3 V reference as the reference source.
LK12 This link selects whether the part power-on resets to zero-scale or midscale.
Position A ensures that the part power-on resets to midscale.
Position B ensures that the part power-on resets to zero-scale.