Digital Interface; Test Circuits - Analog Devices EVAL-AD5141DBZ User Manual

UG-473

DIGITAL INTERFACE

The EVAL-AD5141DBZ can be configured as an I
digital interface, depending on the position in the A2 jumper
(see Table 4).
Table 4. Interface Selection
A2 Jumper Position Digital Interface
A SPI
B I 2 C
If the part is configured in I
2
select the I 2 C address (see Table 5).
Table 5. I 2 C Address Selection
A3 Jumper Position A4 Jumper Position
A A
A B
B A
B B

TEST CIRCUITS

The EVAL-AD5141DBZ and EVAL-MB-LV-SDZ incorporate
several test circuits to evaluate the performance of the AD5141.
DAC
The digiPOT can be operated as a digital-to-analog converter
(DAC), as shown in Figure 2. Table 6 and Figure 7 describe the
options available for the voltage references.
2 C or SPI
C mode, the A3 and A4 jumpers
Address
0101111
0100011
0101100
0100000
V
1kHz
HPF
AC_INPUT
The output voltage is defined in Equation 1.
=
V
OUT
where:
RDAC1 is the code loaded in the RDAC1 register.
V is the voltage applied to the A terminal (A9 link).
A
V is the voltage applied to the B terminal (A10 link).
B
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
Table 6. DAC Voltage References Motherboard Links
Terminal
A1
W1
B1
Table 7. DAC Voltage References Daughter Board Links
Link
A6
A7
A8
A1
DD
2
AC+
AC
R34
A1
RDAC
A
W1
BUF-W1
W
B
B1
R35
BIAS
V
DD
2
VSS
V
SS
AGND
Figure 2. DAC
Rev. 0 | Page 4 of 20
Evaluation Board User Guide
RDAC1
− ×
( V V )
A B
256
A
Link Options Description
A9 AC+ Connects Terminal A1 to V
VDD Connects Terminal A1 to V
BUF-W1 Connects Terminal W1 to an
output buffer
A10 BIAS Connects Terminal B1 to V
VSS Connects Terminal B1 to V
AGND Connects Terminal B1 to
analog ground
Options Description
B Connects Terminal A to A1
B Connects Terminal W to W1
B Connects Terminal B to B1
IN Closes feedback loop of second op amp
in the AD8618
VOUT1
(1)
and V in Equation 1.
B
/2
DD
DD
/2
DD
SS