Datasheet

EVAL-AD5233SDZ User Guide UG-350
Rev. 0 | Page 5 of 16
R43 and R42 can be used to set the maximum and minimum
gain limits.
In addition, R36 can be used to achieve a pseudologarithmic
attenuation. To do so, adjust the R36 resistor until a desirable
transfer function is found.
The inverting amplifier with linear gain is shown in Figure 6,
and the gain is defined in Equation 5.
Signal Amplifier
RDAC2 can be operated as an inverting or noninverting signal
amplifier supporting linear or pseudologarithmic gains. Tabl e 6
shows the available configurations.
R38
R
G
WB2
=
(5)
where R
WB2
is the resistor between the W2 and B2 terminals.
Table 6. Amplifier Selection Link Options
V
IN
RDAC2
B2
R42
W2
B2
W2
V
OUT
OAVOUT
C1
10nF
R41
1.7k
R38
2.7k
10368-006
Amplifier Gain Link Label
1
Noninverting Linear A27 LINEAR
A29 NON-INVERTING
A30 NON-INVERTING
Pseudologarithmic A27 PSEUDOLOG
A29 NON-INVERTING
A30 NON-INVERTING
Inverting Linear A27 LINEAR
A29 INVERTING
A30 INVERTING
Pseudologarithmic A27 PSEUDOLOG
A29 INVERTING
A30 INVERTING
Figure 6. Linear Inverting Amplifier
The inverting amplifier with pseudologarithmic gain is shown
in Figure 7, and the gain is defined in Equation 6.
2
2
AW
WB
R
R
G = (6)
where:
R
WB2
is the resistor between the W2 and B2 terminals.
R
AW 2
is the resistor between the A2 and W2 terminals.
1
See Figure 17.
The noninverting amplifier with linear gain is shown in Figure 4,
and the gain is defined in Equation 3.
R38
R
G
WB2
1+=
(3)
V
IN
RDAC2
B2A2
R42
W2
B2
W2
V
OUT
OAVOUT
A2
C1
10nF
R41
1.7k
R43
10368-007
where R
WB2
is the resistor between the W2 and B2 terminals.
V
IN
RDAC2
B2
R42
W2
B2
W2
V
OUT
OAVOUTC1
10nF
R41
1.7k
R38
2.7k
10368-004
Figure 7. Pseudologarithmic Inverting Amplifier
R43 and R42 can be used to set the maximum and minimum
gain limits.
Output Buffers
Figure 4. Linear Noninverting Amplifier
RDAC3 and RDAC4 can be connected to an output buffer as
shown Figure 8 and Figure 9, respectively.
The noninverting amplifier with pseudologarithmic gain is
shown in Figure 5, and the gain is defined in Equation 4.
VOUT3
RDAC3
A3
B3
BUF_3
A3
B3
W3
W3
10368-008
2
2
1
AW
WB
R
R
G += (4)
where:
R
WB2
is the resistor between the W2 and B2 terminals.
R
AW 2
is the resistor between the A2 and W2 terminals.
Figure 8. RDAC3
V
IN
RDAC2
B2A2
R42
W2
B2
W2
V
OUT
OAVOUT
A2
C1
10nF
R41
1.7k
R43
10368-005
VOUT4
RDAC4
A4
B4
BUF_4
A4
B4
W4
W4
10368-009
Figure 9. RDAC4
Figure 5. Pseudologarithmic Noninverting Amplifier