3
DEMO MANUAL DC2795
UG-1369 Rev 0
Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog
Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications
subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Using External Reference for the DC2795
To use an external reference to drive the DC2795, move
the jumper named V
REF
(JP1) from the VR
EF
position to
the EXT position. Use the REF turret to drive the reference
voltage. If the QuikEval module is being used, the new
reference voltage will need to be manually set.
Using External Supplies for V
CC
As a default, the DC2795 is powered from the DC590/
DC2026. It can be powered by an external supply as well.
Move the jumper labeled V
CC
from 5V Reg to EXT and
connect the low noise supply to the V
CC
turret.
Connectors and Turrets
J1: Interface connector to DC590 controller or Lin-
duino Provides V
CC
power, SPI interface, and board
identification.
V
CC
: Normally V
CC
is supplied by the DC590 or DC2026.
By changing JP2 (V
CC
) an external voltage can be used
to power the DC2789. This voltage should be between
2.7V to 5.5V.
GND: Additional ground posts and exposed ground plane
around the board edge allow solid connection to prototype
circuitry and measurement equipment.
QUICK START PROCEDURE
V
REF
: Connection to the REF pin. In internal reference
mode, the reference voltage may be monitored at this
point. Placing V
REF
jumper in EXT position allows an
external low-noise reference to be connected to this point.
External references should be between 0V and V
CC
.
V
OUTA
– V
OUTH
: Output voltage for DAC channel A−H.
Not channels E−H are not used with the LTC1664, the
DC2795A-C.
Jumpers
V
REF
(JP1): Selects internal or external reference mode.
(Default: VREF).
V
CC
(JP2): Selects between 5V regulated voltage from the
DC590/DC2026 or an external voltage supply. (Default:
5V Reg).
Test Points
The SPI bus is available on a row of through-hole test
points next to J1 that may be used to monitor the bus or
drive the bus with an external controller.
EEGND, WP: For factory use only.
