參數(shù)資料
型號: INA102CG
元件分類: 測量放大器
英文描述: Low Power INSTRUMENTATION AMPLIFIER
中文描述: 低功耗儀表放大器
文件頁數(shù): 6/13頁
文件大?。?/td> 173K
代理商: INA102CG
Ge
CM
CMRR
~
~
~
~
~
e
2
e
1
e
0
Z
a
Z
CM
e
CM
e
d
/2
e
d
/2
Z
d
Z
CM
e
a
e
b
Gain Set
DISCUSSION OF
PERFORMANCE
INSTRUMENTATION AMPLIFIERS
Instrumentation amplifiers are differential-input closed-loop
gain blocks whose committed circuit accurately amplifies the
voltage applied to their inputs. They respond mainly to the
difference between the two input signals and exhibit ex-
tremely high input impedance, both differentially and com-
mon-mode. The feedback networks of this instrumentation
amplifier are included on the monolithic chip. No external
resistors are required for gains of 1, 10, 100, and 1000 in the
INA102.
An operational amplifier, on the other hand, is an open-loop,
uncommitted device that requires external networks to close
the loop. While op amps can be used to achieve the same
basic function as instrumentation amplifiers, it is very diffi-
cult to reach the same level of performance. Using op amps
often leads to design tradeoffs when it is necessary to amplify
low-level signals in the presence of common-mode voltages
while maintaining high-input impedances. Figure 1 shows a
simplified model of an instrumentation amplifier that elimi-
nates most of the problems associated with op amps.
e
O
= e
A
+ e
B
e
A
= G(e
2
– e
1
) = Ge
D
G(e
2
+ e
1
)/2 =
CM
CMRR
CMRR
e
B
=
Gain set is pin-programmable for x1, x10, x100, x1000 in the INA102.
e
O
= Ge
D
+
FIGURE 1. Model of an Instrumentation Amplifier.
THE INA102
A simplified schematic of the INA102 is shown on the first
page. A three-amplifier configuration is used to provide the
desirable characteristics of a premium performance instru-
mentation amplifier. In addition, INA102 has features not
normally found in integrated circuit instrumentation amplifi-
ers.
The input buffers (A
1
and A
2
) incorporate high performance,
low-drift amplifier circuitry. The amplifiers are connected in
the noninverting configuration to provide the high input
impedance (10
10
) desirable in instrumentation amplifier
applications. The offset voltage, and offset voltage versus
temperature, are low due to the monolithic design, and
improved even further by state-of-the-art laser-trimming
techniques.
The output stage (A
3
) is connected in a unity-gain differential
amplifier configuration. A critical part of this stage is the
matching of the four 20k
resistors which provide the
difference function. These resistors must be initially well
matched and the matching must be maintained over tempera-
ture and time in order to retain good common-mode rejec-
tion.
All of the internal resistors are made of thin-film nichrome
on the integrated circuit. The critical resistors are laser-
trimmed to provide the desired high gain accuracy and
common-mode rejection. Nichrome ensures long-term sta-
bility and provides excellent TCR and TCR tracking. This
provides gain accuracy and common-mode rejection when
the INA102 is operated over wide temperature ranges.
USING THE INA102
Figure 2 shows the simplest configuration of the INA102.
The output voltage is a function of the differential input
voltage times the gain.
A gain of 1, 10, 100, or 1000 is selected by programming pins
2 through 7 (see Table I). Notice that for the gain of 1000, a
special gain sense is provided to preserve accuracy. Al-
though this is not always required, gain errors caused by
external resistance in series with the low value 40.04
internal gain set resistor are thus eliminated.
GAIN
CONNECT PINS
1
6 to 7
10
100
1000
2 to 6 and 7
3 to 6 and 7
4 to 7 and separately 5 to 6
TABLE I. Pin-Programmable Gain Connections.
FIGURE 2. Basic Circuit Connection for the INA102.
INA102
~
+In
–In
15
7
6
14
~
e
2
–V
CC
9
11
Gain = 1
Output
12
10
1μF
Tantalum
1μF
Tantalum
10k
+V
CC
相關(guān)PDF資料
PDF描述
INA102KP Low Power INSTRUMENTATION AMPLIFIER
INA103KU Single Supply, Rail-to-Rail, Low Cost Instrumentation Amplifier
INA103 Single Supply, Rail-to-Rail, Low Cost Instrumentation Amplifier
INA103KP Single Supply, Rail-to-Rail, Low Cost Instrumentation Amplifier
INA104 Very-High Accuracy INSTRUMENTATION AMPLIFIER
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
INA102KP 制造商:Texas Instruments 功能描述:SP AMP INSTR AMP TRIPLE 18V 8PDIP - Rail/Tube
INA103 制造商:BB 制造商全稱:BB 功能描述:Low Noise, Low Distortion INSTRUMENTATION AMPLIFIER
INA103_07 制造商:BB 制造商全稱:BB 功能描述:Low Noise, Low Distortion INSTRUMENTATION AMPLIFIER
INA10386 制造商:AGILENT 制造商全稱:AGILENT 功能描述:Low Noise, Cascadable Silicon Bipolar MMIC Amplifier
INA-10386 制造商:AGILENT 功能描述:_