AD5292 Analog Devices, AD5292 Datasheet - Page 24

• Manufacturer Part Number: AD5292
• Description: (AD5291 / AD5292) Digital Potentiometer
• Manufacturer: Analog Devices

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AD5291/AD5292
APPLICATIONS INFORMATION
HIGH VOLTAGE DAC
The AD5292 can be configured as a high voltage DAC, with
output voltage as high as 33 V. The circuit is shown in Figure 49.
The output is
where D is the decimal code from 0 to 1023.
PROGRAMMABLE VOLTAGE SOURCE WITH
BOOSTED OUTPUT
For applications that require high current adjustments such as a
laser diode or a tunable laser, a boosted voltage source can be
considered (see Figure 50).
In this circuit, the inverting input of the op amp forces V
be equal to the wiper voltage set by the digital potentiometer.
The load current is then delivered by the supply via the N-channel
FET (U3). The N-Channel FET power handling must be adequate
to dissipate (V
maximum of 100 mA with a 33 V supply.
ADR512
R
V
BIAS
OUT
V
DD
AD5292
(
D
D1
Figure 50. Programmable Boosted Voltage Source
U1
)
R

1
IN
V
1024
IN
B
− V
A
D
AD8512
V–
Figure 49. High Voltage DAC
OUT

W
V+
V
R




1
DD
OP184
2
) × I
2 .
U1A
V
L
U2

power. This circuit can source a
U3 2N7002




1

U2
AD5292
R
R
B
2
1




20kΩ




SIGNAL
LD
C
C
U1B
AD8512
R
V
BIAS
OUT
I
L
OUT
V
to
Rev. 0 | Page 24 of 28
OUT
(7)
HIGH ACCURACY DAC
It is possible to configure the AD5292 as a high accuracy DAC
by optimizing the resolution of the device over a specific
reduced voltage range. This is achieved by placing external
resistors on either side of the RDAC, as shown in Figure 51.
The improved ±1% resistor tolerance specification greatly
reduces error associated with matching to discrete resistors.
VARIABLE GAIN INSTRUMENTATION AMPLIFIER
The
as shown in Figure 52, make an excellent instrumentation
amplifier for use in data acquisition systems. The data acquisi-
tion system’s low distortion and low noise enable it to condition
signals in front of a variety of ADCs.
The gain can be calculated by using Equation 9.
AD8221
V
G
OUT
+V
+V
–V
–V
(
D
IN1
IN4
IN1
IN4
)
(

D
1
)
in conjunction with the AD5292 and the ADG1207,


U1
AD5292
ADG1207

R
D
Figure 52. Data Acquisition System
1
Figure 51. Optimizing Resolution
20kΩ
1024
R
49

3
R
R
R
4 .

1
2
3
B
(
V
(
DD
kΩ

(
1024
D
±1%

1024
R

D
AB
)

AD5292
1024
R
)
AB
OP1177

V+
)
U2
V–
R

V
AB
V
DD
DD

R
AD8221
3
V
V
DD
SS
V
OUT
V
OUT
(8)
(9)