Datasheet

®
INA105
5
COMMON-MODE INPUT RANGE vs SUPPLY
(Difference Amplifier Connected, V
OUT
= 0)
Supply Voltage (V)
±3
Input Range (V)
36
30
24
18
12
6
0
±6 ±9 ±12 ±15 ±18 ±21
Negative CMV
Positive CMV
POWER SUPPLY REJECTION
vs FREQUENCY
Frequency (Hz)
1
PSRR (dB)
140
120
100
80
60
40
10 100 1k 10k 100k
V–
V+
TYPICAL PERFORMANCE CURVES (CONT)
At T
A
= 25°C, V
S
= ±15V, unless otherwise noted.
APPLICATION INFORMATION
Figure 1 shows the basic connections required for operation
of the INA105. Power supply bypass capacitors should be
connected close to the device pins.
The differential input signal is connected to pins 2 and 3 as
shown. The source impedances connected to the inputs must
be nearly equal to assure good common-mode rejection. A
5Ω mismatch in source impedance will degrade the com-
mon-mode rejection of a typical device to approximately
80dB. If the source has a known mismatch in source imped-
ance, an additional resistor in series with one input can be
used to preserve good common-mode rejection.
The output is referred to the output reference terminal (pin
1) which is normally grounded. A voltage applied to the Ref
terminal will be summed with the output signal. This can be
used to null offset voltage as shown in Figure 2. The source
impedance of a signal applied to the Ref terminal should be
less than 10Ω to maintain good common-mode rejection.
Do not interchange pins 1 and 3 or pins 2 and 5, even though
nominal resistor values are equal. These resistors are laser
trimmed for precise resistor ratios to achieve accurate gain
and highest CMR. Interchanging these pins would not pro-
vide specified performance.
FIGURE 1. Basic Power Supply and Signal Connections.
V
3
5
6
3
INA105
V
OUT
= V
3
– V
2
2
R
3
R
1
R
2
R
4
V
2
25k
Ω
25k
Ω
25k
Ω
25k
Ω
1µF
V–
4
1µF
V+
7
1