EVAL-AD5678DBZ User Guide UG-987
Rev. A | Page 3 of 13
EVALUATION BOARD HARDWARE
MOTHERBOARD POWER SUPPLIES
The EVAL-MBnanoDAC-SDZ motherboard supports single
and dual power supplies.
The EVAL-AD5678DBZ evaluation board can be powered either
from the SDP port or externally by the J5 and J6 connectors, as
described in Table 1.
Both the AGND and DGND inputs are provided on the board.
The AGND and DGND planes are connected at one location on
the EVAL-MBnanoDAC-SDZ. It is recommended that AGND
and DGND not be connected elsewhere in the system to avoid
ground loop problems.
All supplies are decoupled to ground with 10 µF tantalum and
0.1 µF ceramic capacitors.
Table 1. Power Supply Connectors
Connector No. Label Voltage
Analog positive power supply, V
DD
Single supply 5 V, dual supply 5 V.
J5, Pin 2 (J5-2) AGND Analog ground.
J5, Pin 3 (J5-3) VSS Analog negative power supply, VSS.
Dual supply −5 V.
J6, Pin 1 (J6-1) VLOGIC Digital supply from 1.8 V to VDD.
LINK OPTIONS
A number of link options are incorporated in the E VA L -
MBnanoDAC-SDZ and must be set for the required operating
conditions before using the board. Table 2 describes the positions of
the links to control the evaluation board via the SDP-B board
using a PC and external power supplies. The functions of these
link options are described in detail in Table 3. The positions listed
in Table 2 and Table 3 match the evaluation board imprints (see
Figure 12).
Table 2. Link Options Setup for SDP-B Control (Default)
Link No. Position
REF1 EXT
REF2 EXT
REF3 EXT
LK5 C
LK6 3.3V
LK7 B
Table 3. Link Functions
Link Number Function
REF1 to REF4 These links select the reference source.
Position EXT selects an off-board voltage reference via the appropriate EXT_REF_x connector.
Position VDD selects VDD as the reference source.
Position 4.096V selects the on-board 4.096 V reference as the reference source.
Position 2.5V selects the on-board 2.5 V reference as the reference source.
Position 5V selects the on-board 5 V reference as the reference source, V
DD
LK5 This link selects the positive DAC analog voltage source.
Position A selects the internal voltage source from the SDP-B board.
Position B selects the internal voltage source 3.3 V from the ADP121 on the motherboard.
Position C selects an external supply voltage, VDD.
This link selects the VLOGIC voltage source.
Position 3.3V selects the digital voltage source from the SDP-B board, 3.3 V.
Position VLOGIC selects an external digital supply voltage, VLOGIC.
This link selects the negative DAC analog voltage source.
Position A selects VSS.
Position B selects AGND.
