EVAL-AD5620EB/EVAL-AD5640EB/EVAL-AD5660EB/EVAL-AD5662EB
Rev. 0 | Page 3 of 12
OPERATING THE AD56XX EVALUATION BOARD
POWER SUPPLIES
The AD56xx evaluation board can be powered from the USB
port. This is the default setup. It can also be powered by an
external supply using the J6 and J7 power connectors.
Both analog GND and DGND inputs are provided on the
board. The analog GND and DGND planes are connected at
one location close to the AD56xx. It is recommended not to
connect analog GND and DGND elsewhere in the system to
avoid ground loop problems.
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.
Tabl e 1 lists the default link options. 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.
Table 1. Link Options Setup for PC Controls
Link No. Option (Default)
LK1 INSERTED
LK2 A
LK3 REMOVED
LK4 A (AD5620/AD5640/AD5660)
B (AD5662 only)
LK5 B
LK6 B
LK7 INSERTED (AD5620/AD5640/AD5660)
REMOVED (AD5662 only)
LK8 INSERTED
LK9 INSERTED
Table 2. Link Options
Link No. Function
LK1 This link connects the VFB pin to the V
OUT
pin of the AD56xx.
LK2
This link selects whether the AD56xx evaluation board is controlled by the PC via the USB port or by an external source via the
J1, J3, and J4 SMB connectors.
• Position A: The evaluation board is controlled by the PC via the USB port.
• Position B: The evaluation board is controlled by an external source via the J1, J3, and J4 SMB connectors.
LK3 This link connects external resistors and capacitor loads to the V
OUT
pin of the AD56xx.
LK4 This link selects the reference source.
• Position A: The internal reference is the reference source (AD5660/AD5640/AD5620).
• Position B: The on-board 2.5 V/3 V AD780 reference is the reference source (AD5662 only).
LK5 This link selects the AVDD power supply source for the analog circuitry.
• Position A: J6 is the AVDD analog circuitry power supply source.
• Position B: The USB 5 V power supply is the AVDD analog circuitry power supply source.
LK6 This link selects the DVDD power supply source for the digital circuitry.
• Position A: J7 is the DVDD digital circuitry power supply source.
• Position B: The USB 5 V power supply source is the digital circuitry power supply source.
LK7 This link connects a 0.1 μF capacitor to GND on the VREF output pin of the device (AD5620/AD5640/AD5660).
LK8
This link connects the OP_SEL pin of the AD780 reference to ground, selecting a 3 V output. Leaving no connect gives a
2.5 V output.
LK9
This link connects the V
OUT
pin of the AD56xx to the V
IN
pin of the AD7476 ADC so that the DAC output value can be monitored
using the on-board ADC.
