参数资料
| 型号： | AD623ANZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 11/24页 |
| 文件大小： | 0K |
| 描述： | IC AMP INST R-R LP 8DIP |
| 产品培训模块： | Instrumentation Amplifiers Performance |
| 标准包装： | 50 |
| 放大器类型： | 仪表 |
| 电路数： | 1 |
| 输出类型： | 满摆幅 |
| 转换速率： | 0.3 V/µs |
| -3db带宽： | 800kHz |
| 电流 - 输入偏压： | 17nA |
| 电压 - 输入偏移： | 25µV |
| 电流 - 电源： | 375µA |
| 电压 - 电源，单路/双路(±)： | 2.7 V ~ 12 V，± 2.5 V ~ 6 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 通孔 |
| 封装/外壳： | 8-DIP（0.300"，7.62mm） |
| 供应商设备封装： | 8-PDIP |
| 包装： | 管件 |
| 产品目录页面： | 770 (CN2011-ZH PDF) |
AD623
Rev. D | Page 19 of 24
Ground Returns for Input Bias Currents
Input bias currents are those dc currents that must flow to bias
the input transistors of an amplifier. These are usually transistor
base currents. When amplifying floating input sources, such as
transformers or ac-coupled sources, there must be a direct dc
path into each input in order that the bias current can flow.
path can be provided for the cases of transformer coupling,
thermocouple, and capacitive ac coupling. In dc-coupled resistive
bridge applications, providing this path is generally not necessary
as the bias current simply flows from the bridge supply through
the bridge into the amplifier. However, if the impedances that
the two inputs see are large and differ by a large amount (>10 kΩ),
the offset current of the input stage causes dc errors
proportional with the input offset voltage of the amplifier.
AD623
OUTPUT
TO POWER
SUPPLY
GROUND
REF
LOAD
+VS
–VS
2
1
8
3
6
5
7
4
RG
–IN
+IN
007
78
-04
8
Figure 49. Ground Returns for Bias Currents with Transformer-Coupled Inputs
AD623
OTUPUT
TO POWER
SUPPLY
GROUND
REF
LOAD
+VS
–VS
2
1
8
3
6
5
7
4
RG
–IN
+IN
00
77
8-
0
49
Figure 50. Ground Returns for Bias Currents with Thermocouple Inputs
AD623
OUTPUT
TO POWER
SUPPLY
GROUND
REF
LOAD
+VS
–VS
2
1
8
3
6
5
7
4
RG
–IN
+IN
100k
00
77
8-
0
50
Figure 51. Ground Returns for Bias Currents with AC-Coupled Inputs
Output Buffering
The AD623 is designed to drive loads of 10 kΩ or greater. If
the load is less than this value, the output of the AD623 should
be buffered with a precision single-supply op amp, such as the
OP113. This op amp can swing from 0 V to 4 V on its output
while driving a load as small as 600 Ω. Table 7 summarizes the
performance of some buffer op amps.
5V
0.1F
5V
0.1F
AD623
OP113
RG
VIN
REFERENCE
VOUT
00
77
8-
05
1
Figure 52. Output Buffering
Table 7. Buffering Options
Op Amp
Description
Single supply, high output current
Rail-to-rail input and output, low supply current
Single-Supply Data Acquisition System
Interfacing bipolar signals to single-supply ADCs presents a
challenge. The bipolar signal must be mapped into the input
range of the ADC. Figure 53 shows how this translation can be
achieved.
5V
0.1F
5V
0.1F
AD623
RG
1.02k
REFERENCE
±10mV
AIN
REFOUT
REFIN
AD7776
00
77
8-
05
2
Figure 53. A Single-Supply Data Acquisition System
The bridge circuit is excited by a 5 V supply. The full-scale output
voltage from the bridge (±10 mV) therefore has a common-
mode level of 2.5 V. The AD623 removes the common-mode
component and amplifies the input signal by a factor of 100
(RGAIN = 1.02 kΩ). This results in an output signal of ±1 V. To
prevent this signal from running into the ground rail of the
AD623, the voltage on the REF pin must be raised to at least
1 V. In this example, the 2 V reference voltage from the AD7776
ADC is used to bias the output voltage of the AD623 to 2 V ± 1 V.
This corresponds to the input range of the ADC.
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相关代理商/技术参数 |
参数描述 |
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| AD623AR | 功能描述:IC AMP INST R-R LP 8SOIC RoHS:否 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 标准包装:50 系列:- 放大器类型:J-FET 电路数:2 输出类型:- 转换速率:3.5 V/µs 增益带宽积:1MHz -3db带宽:- 电流 - 输入偏压:30pA 电压 - 输入偏移:2000µV 电流 - 电源:200µA 电流 - 输出 / 通道:- 电压 - 电源，单路/双路(±):7 V ~ 36 V，±3.5 V ~ 18 V 工作温度:0°C ~ 70°C 安装类型:通孔 封装/外壳:8-DIP（0.300"，7.62mm） 供应商设备封装:8-PDIP 包装:管件 |
| AD623AR | 制造商:Analog Devices 功能描述:SEMICONDUCTORS |
| AD623ARM | 制造商:Analog Devices 功能描述:SP Amp INSTR Amp Single R-R O/P 制造商:Analog Devices 功能描述:IC AMP INSTRUMENTATION |
| AD623ARM-REEL | 制造商:Analog Devices 功能描述:SP Amp INSTR Amp Single R-R O/P |
| AD623ARM-REEL7 | 制造商:Analog Devices 功能描述:SP Amp INSTR Amp Single R-R O/P |
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