Datasheet

Evaluation Board User Guide UG-391
Rev. 0 | Page 5 of 16
SIGNAL AMPLIFIER
The RDAC can be operated as an inverting or noninverting
signal amplifier supporting linear or pseudologarithmic gains.
Table 6 shows the available configurations.
The noninverting amplifier with linear gain is shown in Figure 4,
and the gain is defined in Equation 3.
R38
R
G
WB
1
(3)
where R
WB
is the resistor between the W and B terminals.
VOUT2
V
IN
RDAC
R42
C1
10nF
W2
B2
WB
R41
1.7kΩ
R38
2.7kΩ
10619-004
Figure 4. Linear Noninverting Amplifier
The noninverting amplifier with pseudologarithmic gain is
shown in Figure 5, and the gain is defined in Equation 4.
AW
WB
R
R
G 1 (4)
where:
R
WB
is the resistor between the W and B terminals.
R
AW
is the resistor between the A and W terminals.
VOUT2
V
IN
RDAC
R42
C1
10nF
W2
B2
AB
W
R41
1.7kΩ
A2
R43
10619-005
Figure 5. Pseudologarithmic Noninverting Amplifier
R43 and R42 can be used to set the maximum and minimum
gain limits.
The inverting amplifier with linear gain is shown in Figure 6,
and the gain is defined in Equation 5.
Note that the input signal, V
IN
, must be negative.
R38
R
G
WB

(5)
where R
WB
is the resistor between the W and B terminals.
VOUT2
V
IN
RDAC
R42
C1
10nF
W2
B2
WB
R41
1.7kΩ
R38
2.7kΩ
10619-006
Figure 6. Linear Inverting Amplifier
Table 6. Amplifier Selection Link Options
Amplifier Gain Link (Daughter Board) Link (Motherboard) Label V
IN
Range
Noninverting Linear Switch A of A2, A3, and A4 A7 LIN 0 V to V
DD
A6 N-INV
A1 not inserted A8 N-INV
Pseudologarithmic Switch A of A2, A3, and A4 A7 LOC 0 V to V
DD
A6 N-INV
A1 not inserted A8 N-INV
Inverting Linear Switch A of A2, A3, and A4 A7 LIN −V
DD
to 0 V
A6 INV
A1 not inserted A8 INV