Datasheet

®
INA103
8
TYPICAL PERFORMANCE CURVES (CONT)
At T
A
= +25°C, V
S
= ±15V unless, otherwise noted.
APPLICATIONS INFORMATION
Figure 1 shows the basic connections required for operation.
Power supplies should be bypassed with 1µF tantalum
capacitors near the device pins. The output Sense (pin 11)
and output Reference (pin 7) should be low impedance
connections. Resistance of a few ohms in series with these
connections will degrade the common-mode rejection of the
amplifier.
To avoid oscillations, make short, direct connection to the
gain set resistor and gain sense connections. Avoid running
output signals near these sensitive input nodes.
INPUT CONSIDERATIONS
Certain source impedances can cause the INA103 to oscil-
late. This depends on circuit layout and source or cable
characteristics connected to the input. An input network
consisting of a small inductor and resistor (Figure 2) can
greatly reduce the tendancy to oscillate. This is especially
useful if various input sources are connected to the INA103.
Although not shown in other figures, this network can be
used, if needed, with all applications shown.
GAIN SELECTION
Gains of 1 or 100V/V can be set without external resistors.
For G = 1V/V (unity gain) leave pin 14 open (no connec-
tion)—see Figure 4. For G = 100V/V, connect pin 14 to pin
6—see Figure 5.
Gain can also be accurately set with a single external resistor
as shown in Figure 1. The two internal feedback resistors are
laser-trimmed to 3kΩ within approximately ±0.1%. The
temperature coefficient of these resistors is approximately
50ppm/˚C. Gain using an external R
G
resistor is—
G = 1 +
6kΩ
R
G
1
0.1
0.010
0.001
SMPTE IMD (%)
SMPTE IMD vs FREQUENCY
Frequency (Hz)
5
2k 10k 20k
0.0005
G = 1000
G = 100
G = 1
G = 10
CURRENT NOISE SPECTRAL DENSITY
100
Current Noise Density (pA/ Hz)
1 10 100 1k 10k
Frequency (Hz)
1
10