AMP02FS Analog Devices Inc, AMP02FS Datasheet - Page 8
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AMP02FS
Manufacturer Part Number
AMP02FS
Description
Instrumentation Amplifier IC
Manufacturer
Analog Devices Inc
Datasheet
1.AMP02FSZ-RL.pdf
(12 pages)
Specifications of AMP02FS
No. Of Amplifiers
2
Slew Rate
6V/µs
Amplifier Case Style
SOIC
No. Of Pins
16
Programmable Gain Max
10000
Mounting Type
Surface Mount
Supply Voltage Min
4.5V
Gain Min, V/v
1
Gain Max, V/v
10000
Rohs Status
RoHS non-compliant
Amplifier Type
Instrumentation
Number Of Circuits
1
-3db Bandwidth
1.2MHz
Current - Input Bias
4nA
Voltage - Input Offset
40µV
Current - Supply
5mA
Current - Output / Channel
32mA
Voltage - Supply, Single/dual (±)
±4.5 V ~ 18 V
Operating Temperature
-40°C ~ 85°C
Package / Case
16-SOIC (0.300", 7.5mm Width)
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Output Type
-
Gain Bandwidth Product
-
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
AMP02FS
Manufacturer:
ADI/亚德诺
Quantity:
20 000
Company:
Part Number:
AMP02FSZ
Manufacturer:
ANALOGDEVICE
Quantity:
844
Part Number:
AMP02FSZ
Manufacturer:
ADI/亚德诺
Quantity:
20 000
AMP02
APPLICATIONS INFORMATION
Input and Output Offset Voltages
Instrumentation amplifiers have independent offset voltages
associated with the input and output stages. The input offset
component is directly multiplied by the amplifier gain, whereas
output offset is independent of gain. Therefore at low gain,
output-offset errors dominate while at high gain, input-offset
errors dominate. Overall offset voltage, V
output (RTO) is calculated as follows:
where V
specifications and G is the amplifier gain.
The overall offset voltage drift TCV
a combination of input and output drift specifications. Input
offset voltage drift is multiplied by the amplifier gain, G, and
summed with the output offset drift:
where TCV
the output offset voltage drift. Frequently, the amplifier drift is
referred back to the input (RTI), which is then equivalent to an
input signal change:
For example, the maximum input-referred drift of an
AMP02EP set to G = 1000 becomes:
Input Bias and Offset Currents
Input transistor bias currents are additional error sources that
can degrade the input signal. Bias currents flowing through the
signal source resistance appear as an additional offset voltage.
Equal source resistance on both inputs of an IA will minimize
offset changes due to bias current variations with signal voltage
and temperature; however, the difference between the two bias
currents (the input offset current) produces an error. The mag-
nitude of the error is the offset current times the source resistance.
A current path must always be provided between the differential
inputs and analog ground to ensure correct amplifier operation.
Floating inputs such as thermocouples should be grounded
close to the signal source for best common-mode rejection.
Gain
The AMP02 only requires a single external resistor to set the
voltage gain. The voltage gain, G, is:
and
TCV
IOS
OS
TCV
IOS
and V
(
RTI
TCV
is the input offset voltage drift, and TCV
OS
V
OOS
OS
)
(
OS
RTO
=
(
RTO
are the input and output offset voltage
2
(
RTI
µ
V C
)
G =
R
=
)
)
G
=
(
o
=
TCV
=
50 kΩ
(
TCV
V
R
+
50 kΩ
IOS
G – 1
G
100
IOS
OS
IOS
×
+1
1000
, referred to the output, is
×
G
µ
+
G
V C
)
OS
+
TCV
)
o
V
+
, referred to the
OOS
G
TCV
OOS
=
2 1
.
OOS
µ
V C
OOS
o
is
–8–
The voltage gain can range from 1 to 10,000. A gain set resistor is
not required for unity-gain applications. Metal-film or wirewound
resistors are recommended for best results.
The total gain accuracy of the AMP02 is determined by the
tolerance of the external gain set resistor, R
gain equation accuracy of the AMP02. Total gain drift combines
the mismatch of the external gain set resistor drift with that of the
internal resistors (20 ppm/°C typ). Maximum gain drift of the
AMP02 independent of the external gain set resistor is 50 ppm/°C.
All instrumentation amplifiers require attention to layout so
thermocouple effects are minimized. Thermocouples formed
between copper and dissimilar metals can easily destroy the
TCV
Resistors themselves can generate thermoelectric EMFs when
mounted parallel to a thermal gradient.
The AMP02 uses the triple op amp instrumentation amplifier
configuration with the input stage consisting of two transimped-
ance amplifiers followed by a unity-gain differential amplifier.
The input stage and output buffer are laser-trimmed to increase
gain accuracy. The AMP02 maintains wide bandwidth at all
gains as shown in Figure 3. For voltage gains greater than 10,
the bandwidth is over 200 kHz. At unity gain, the bandwidth of
the AMP02 exceeds 1 MHz.
Common-Mode Rejection
Ideally, an instrumentation amplifier responds only to the differ-
ence between the two input signals and rejects common-mode
voltages and noise. In practice, there is a small change in output
voltage when both inputs experience the same common-mode
voltage change; the ratio of these voltages is called the
common-mode gain. Common-mode rejection (CMR) is the
logarithm of the ratio of differential-mode gain to common-mode
gain, expressed in dB. Laser trimming is used to achieve the
high CMR of the AMP02.
Figure 3. The AMP02 Keeps Its Bandwidth at
High Gains
OS
performance of the AMP02, which is typically 0.5 µV/°C.
–20
–40
80
60
40
20
0
1k
G = 1000
G = 100
G = 10
G = 1
10k
FREQUENCY – Hz
100k
G
1M
, combined with the
T
V
A
S
= 25 C
=
15V
10M
REV. E