UG-469
Evaluation Board User Guide
Rev. 0 | Page 4 of 20
TEST CIRCUITS
The
EVAL-AD5144DBZ
and EVAL-MB-LV-SDZ incorporate
several test circuits to evaluate the performance of the
AD5144
.
DAC
The digiPOT can be operated as a digital-to-analog converter
(DAC), as shown in Figure 2. Table 4 describes the options
available for the voltage references.
The output voltage is defined in Equation 1.
256
)
(
RDAC1
V
V
V
B
A
OUT
×
−
=
(1)
where:
RDAC1
is the code loaded in the RDAC1 register.
V
A
is the voltage applied to the A terminal (A9 link).
V
B
is the voltage applied to the B terminal (A10 link).
However, by using the R34 and R35 external resistors, the user
can reduce the voltage of the voltage references. In this case, use
the A1 and B1 test points to measure the voltage applied to the
A and B terminals and to recalculate V
A
and V
B
in Equation 1.
Table 4. DAC Voltage References
Terminal
Link
Options
Description
A1
A9
AC+
Connects Terminal A1 to V
DD
/2
VDD
Connects Terminal A1 to V
DD
W1
BUF-W1
Connects Terminal W1 to an
output buffer
B1
A10
BIAS
Connects Terminal B1 to V
DD
/2
VSS
Connects Terminal B1 to V
SS
AGND
Connects Terminal B1 to
analog ground
1
1006-
002
VOUT1
R34
R35
A1
W1
RDAC1
A1
B1
W1
VDD
V
DD
AC+
V
DD
2
V
DD
2
AGND
BIAS
B1
VSS
V
SS
BUF-W1
Figure 2. DAC
