AD5233BRUZ50 Analog Devices Inc, AD5233BRUZ50 Datasheet - Page 24

• Manufacturer Part Number: AD5233BRUZ50
• Description: IC,Digital Potentiometer,CMOS,TSSOP,24PIN,PLASTIC
• Manufacturer: Analog Devices Inc

Specifications of AD5233BRUZ50

• Taps: 64
• Resistance (ohms): 50K
• Number Of Circuits: 4
• Temperature Coefficient: 600 ppm/°C Typical
• Memory Type: Non-Volatile
• Interface: 4-Wire SPI Serial
• Voltage - Supply: 2.7 V ~ 5.5 V, ±2.25 V ~ 2.75 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 24-TSSOP
• Resistance In Ohms: 50K
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD5233
BIPOLAR PROGRAMMABLE GAIN AMPLIFIER
There are several ways to achieve bipolar gain. Figure 50 shows
one versatile implementation. Digital potentiometer, U1, sets
the adjustment range; therefore, the wiper voltage, V
programmed between V
Configuring A2 as a noninverting amplifier yields a linear
transfer function:
where:
K is the ratio of R
D is the decimal equivalent of the input code.
In the simpler (and much more usual) case where K is 1, a
pair of matched resistors can replace U1. Equation 4 can be
simplified to
Table 19 shows the result of adjusting D with A2 configured as a
unity gain, a gain of 2, and a gain of 10. The result is a bipolar
amplifier with linearly programmable gain and 64-step resolution.
Table 19. Result of Bipolar Gain Amplifier
D
0
16
32
48
63
V
V
V
V
V
i
AD5233
O
O
i
i
=
=
AD5233
⎛ +
⎜
⎝
⎛ +
⎜
⎝
Figure 50. Bipolar Programmable Gain Amplifier
1
1
R1 = ∞, R2 = 0
−1
−0.5
0
0.5
0.968
A2
U1
R2
U2
A1
R2
R1
R1
WB
⎞
⎟
⎠
⎞
⎟
⎠
W2
/R
×
B1
W1
×
B2
A1
OP2177
⎛
⎜
⎝
WA
⎛
⎜
⎝
2
D2
64
i
V+
V–
64
D
that is set by U1.
and −KV
V
V
DD
SS
2
×
−
1 (
1
+
⎞
⎟
⎠
K
R1 = R2
−2
−1
0
1
1.937
i
)
at a given U2 setting.
–KV
−
i
K
A2
OP2177
⎞
⎟
⎠
V+
V–
V
V
DD
SS
R2
R1
R2 = 9 × R1
−10
−5
0
5
9.680
W2
V
O
, can be
C
Rev. B | Page 24 of 32
(4)
(5)
PROGRAMMABLE LOW-PASS FILTER
The AD5233 digital potentiometer can be used to construct a
second-order Sallen-Key low-pass filter, as shown in Figure 51.
The design equations are
where:
Q is the Q factor.
V
R1 and R2 are R
To achieve maximal flat bandwidth where Q is 0.707, let C1
be twice the size of C2 and let R1 equal R2. Users can first
select convenient values for the capacitors and then gang and
move R1 and R2 together to adjust the −3 dB corner frequency.
Instruction 5, Instruction 7, Instruction 13, and Instruction 15
of the AD5233 make these changes simple to implement.
O
is the resonant frequency.
V
ω
Q
V
V
i
O
O
i
=
=
=
R1
S
A
×
R
2
R1
1
TOGETHER
R1
GANGED
+
C1
W
×
WB1
B
ω
Figure 51. Sallen-Key Low-Pass Filter
Q
ω
R2
+
O
O
and R
R2
S
2
1
×
A
R
+
C1
R2
×
1
ω
W
C2
C2
B
O
×
WB2
2
C2
, respectively.
C1
AD8601
+2.5V
–2.5V
V+
V–
U1
V
O
(6)
(7)
(8)