參數(shù)資料
型號: INA128
元件分類: 測量放大器
英文描述: microPower, Single-Supply, CMOS Instrumentation Amplifier
中文描述: 微功耗,單電源,儀表放大器的CMOS
文件頁數(shù): 9/10頁
文件大小: 245K
代理商: INA128
OFFSET TRIMMING
The INA128/INA129 is laser trimmed for low offset voltage
and offset voltage drift. Most applications require no exter-
nal offset adjustment. Figure 2 shows an optional circuit for
trimming the output offset voltage. The voltage applied to
Ref terminal is summed with the output. The op amp buffer
provides low impedance at the Ref terminal to preserve good
common-mode rejection.
INPUT BIAS CURRENT RETURN PATH
The input impedance of the INA128/INA129 is extremely
high—approximately 10
10
. However, a path must be pro-
vided for the input bias current of both inputs. This input
bias current is approximately
±
2nA. High input impedance
means that this input bias current changes very little with
varying input voltage.
Input circuitry must provide a path for this input bias current
for proper operation. Figure 3 shows various provisions for
an input bias current path. Without a bias current path, the
inputs will float to a potential which exceeds the common-
mode range, and the input amplifiers will saturate.
If the differential source resistance is low, the bias current
return path can be connected to one input (see the thermo-
couple example in Figure 3). With higher source impedance,
using two equal resistors provides a balanced input with
possible advantages of lower input offset voltage due to bias
current and better high-frequency common-mode rejection.
INPUT COMMON-MODE RANGE
The linear input voltage range of the input circuitry of the
INA128/INA129 is from approximately 1.4V below the
positive supply voltage to 1.7V above the negative supply.
As a differential input voltage causes the output voltage
increase, however, the linear input range will be limited by
the output voltage swing of amplifiers A
1
and A
2
. So the
FIGURE 2. Optional Trimming of Output Offset Voltage.
10k
OPA177
±10mV
Adjustment Range
100
100
100μA
1/2 REF200
100μA
1/2 REF200
V+
V–
R
G
INA128
Ref
V
O
V
IN
V
IN
+
FIGURE 3. Providing an Input Common-Mode Current Path.
47k
47k
10k
Microphone,
Hydrophone
etc.
Thermocouple
Center-tap provides
bias current return.
INA128
INA128
INA128
linear common-mode input range is related to the output
voltage of the complete amplifier. This behavior also de-
pends on supply voltage—see performance curves “Input
Common-Mode Range vs Output Voltage”.
Input-overload can produce an output voltage that appears
normal. For example, if an input overload condition drives
both input amplifiers to their positive output swing limit, the
difference voltage measured by the output amplifier will be
near zero. The output of A
3
will be near 0V even though both
inputs are overloaded.
LOW VOLTAGE OPERATION
The INA128/INA129 can be operated on power supplies as
low as
±
2.25V. Performance remains excellent with power
supplies ranging from
±
2.25V to
±
18V. Most parameters
vary only slightly throughout this supply voltage range—see
typical performance curves. Operation at very low supply
voltage requires careful attention to assure that the input
voltages remain within their linear range. Voltage swing
requirements of internal nodes limit the input common-
mode range with low power supply voltage. Typical perfor-
mance curves, “Input Common-Mode Range vs Output
Voltage” show the range of linear operation for
±
15V,
±
5V,
and
±
2.5V supplies.
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
INA128/INA129 制造商:BB 制造商全稱:BB 功能描述:INA128. INA129 - Precision. Low Power INSTRUMENTATION AMPLIFIERS
INA128HD 功能描述:儀表放大器 High Temp Prec Lo Pwr Instr Amp RoHS:否 制造商:Texas Instruments 通道數(shù)量: 輸入補償電壓:150 V 可用增益調(diào)整: 最大輸入電阻:10 kOhms 共模抑制比(最小值):88 dB 工作電源電壓:2.7 V to 36 V 電源電流:200 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:MSOP-8 封裝:Bulk
INA128-HT 制造商:TI 制造商全稱:Texas Instruments 功能描述:Precision, Low Power INSTRUMENTATION AMPLIFIERS
INA128P 功能描述:儀表放大器 Precision Low Power Instrumentation Amp RoHS:否 制造商:Texas Instruments 通道數(shù)量: 輸入補償電壓:150 V 可用增益調(diào)整: 最大輸入電阻:10 kOhms 共模抑制比(最小值):88 dB 工作電源電壓:2.7 V to 36 V 電源電流:200 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:MSOP-8 封裝:Bulk
INA128P 制造商:Texas Instruments 功能描述:IC AMP INSTRUMENTATION