Analog Devices AD5252 Evaluation Board EVAL-AD5252SDZ EVAL-AD5252SDZ Ficha De Dados
Códigos do produto
EVAL-AD5252SDZ
UG-274
Evaluation Board User Guide
Rev. 0 | Page 4 of 16
TEST CIRCUITS
The EVAL-AD5252SDZ incorporates several test circuits to
evaluate the
evaluate the
performance.
DAC
RDAC1 can be operated as a digital-to-analog converter (DAC),
as shown in Figure 2.
as shown in Figure 2.
09820-
002
W1_BUF
A1
RDAC1
AC + DC
VDD
A1
B1
BUF-W1
VSS
GND
DC
2
V
DD
– V
SS
V
DD
2
V
DD
– V
SS
V
SS
R34
R35
W1
W1
B1
Figure 2. DAC
Table 4 shows the options available for the voltage references.
Table 4. DAC Voltage References
Terminal Link
Options Description
A1
A20
AC + DC Connects Terminal A1 to
(V
DD
− V
SS
)/2.
VDD
Connects Terminal A1 to V
DD
.
W1
BUF-W1
Connects Terminal W1 to an
output buffer.
output buffer.
B1
A21
DC
Connects Terminal B1 to
(V
(V
DD
− V
SS
)/2.
VSS
Connects Terminal B1 to V
SS
.
GND
Connects Terminal B1 to
analog ground.
analog ground.
The output voltage is defined in Equation 1.
256
)
(
WB1
B1
A1
OUT
R
V
V
V
×
−
=
(1)
where:
R
WB1
is the resistor between the W1 and B1 terminals.
V
A1
is the voltage applied to the A1 terminal (A20 link).
V
B1
is the voltage applied to the B1 terminal (A21 link).
Using the R34 and R35 external resistors, you 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 A1 and B1
terminals and recalculate V
voltage of the voltage references. In this case, use the A1 and
B1 test points to measure the voltage applied to the A1 and B1
terminals and recalculate V
A1
and V
B1
in Equation 1.
AC Signal Attenuation
RDAC1 can be used to attenuate an ac signal, which must be
provided externally using the AC_INPUT connector, as shown
in Figure 3.
provided externally using the AC_INPUT connector, as shown
in Figure 3.
W1_BUF
A1
RDAC1
AC + DC
AC_INPUT
AC
A1
B1
BUF-W1
GND
2
V
DD
– V
SS
V
SS
R34
R35
W1
W1
B1
1µF
R36
09820-
003
DC
VSS
2
V
DD
– V
SS
Figure 3. AC Signal Attenuator
Depending on the voltage supply rails and the dc offset voltage
of the ac signal, various configurations can be used, as described
in Table 5.
of the ac signal, various configurations can be used, as described
in Table 5.
Table 5. AC Signal Attenuation Link Options
Voltage
Supply
Supply
Maximum
AC Signal
Amplitude Link Options Conditions
AC Signal
Amplitude Link Options Conditions
Single
V
DD
A20
AC + DC No dc offset voltage.
AC signal is outside
the voltage supply
rails due to the
dc offset voltage.
rails due to the
dc offset voltage.
DC offset voltage
≠ V
≠ V
DD
AC
All other conditions.
A21
DC
Use in conjunction
with AC + DC link.
with AC + DC link.
GND
All other conditions.
Dual
V
DD
/V
SS
A20
AC + DC AC signal is outside
the voltage supply
rails due to the
dc offset voltage.
rails due to the
dc offset voltage.
DC offset voltage
≠ 0 V
≠ 0 V
AC
All other conditions.
A21
GND
Use in conjunction
with AC + DC link.
with AC + DC link.
VSS
All other conditions.
1
Recommended to ensure optimal total harmonic distortion (THD) performance.
The signal attenuation is defined in Equation 2.
+
×
=
−
−
END
TO
END
W
WB1
R
R
R
n
Attenuatio
log
20
)
dB
(
(2)
where:
R
WB1
is the resistor between the W1 and B1 terminals.
R
W
is the wiper resistance.
R
END-TO-END
is the end-to-end resistance value.