参数资料
| 型号： | AD8231ACPZ-WP |
| 厂商： | Analog Devices Inc |
| 文件页数： | 10/24页 |
| 文件大小： | 0K |
| 描述： | IC AMP INST R-R 7MHZ 16LFCSP |
| 标准包装： | 64 |
| 放大器类型： | 仪表 |
| 电路数： | 2 |
| 输出类型： | 满摆幅 |
| 转换速率： | 1.1 V/µs |
| 增益带宽积： | 7MHz |
| 电流 - 输入偏压： | 250pA |
| 电压 - 输入偏移： | 4µV |
| 电流 - 电源： | 4mA |
| 电流 - 输出 / 通道： | 70mA |
| 电压 - 电源，单路/双路(±)： | 3 V ~ 6 V，±1.5 V ~ 3 V |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-VQFN 裸露焊盘，CSP |
| 供应商设备封装： | 16-LFCSP-VQ EP（4x4） |
| 包装： | 托盘 - 晶粒 |
| 配用： | AD8231-EVALZ-ND - BOARD EVAL FOR AD8231 |
AD8231
Rev. B | Page 18 of 24
THEORY OF OPERATION
–INB
OUTB
+INB
OUTA
–INA
+INA
REF
–VS
+VS
CS
A0
A1
A2
SDN
AD8231
A1
A3
A4
14k
A2
0
65
86
-0
31
Figure 49. Simplified Schematic
AMPLIFIER ARCHITECTURE
The AD8231 is based on the classic 3-op amp topology. This
topology has two stages: a preamplifier to provide amplification,
followed by a difference amplifier to remove the common-mode
voltage. Figure 49 shows a simplified schematic of the AD8231.
The preamp stage is composed of Amplifier A1, Amplifier A2,
and a digitally controlled resistor network. The second stage is a
gain of 1 difference amplifier composed of Amplifier A3 and
four 14 kΩ resistors. A1, A2, and A3 are all zero drift, rail-to-
rail input, rail-to rail-output amplifiers.
The AD8231 design makes it extremely robust over temperature.
The AD8231 uses an internal thin film resistor to set the gain.
Because all of the resistors are on the same die, gain temperature
drift performance and CMRR drift performance are better than
can be achieved with topologies using external resistors. The
AD8231 also uses an auto-zero topology to null the offsets of all its
internal amplifiers. Because this topology continually corrects for
any offset errors, offset temperature drift is nearly nonexistent.
The AD8231 also includes a free operational amplifier. Like
the other amplifiers in the AD8231, it is a zero drift, rail-to-rail
input, rail-to-rail output architecture.
GAIN SELECTION
The gain of the AD8231 is set by voltages applied to the A0, A1,
and A2 pins. To change the gain, the CS pin must be driven
low. When the CS pin is driven high, the gain is latched, and
voltages at the A0 to A2 pins have no effect. Because the CS pin
is level sensitive rather than edge sensitive, it can also be tied
permanently low.
shows the different gain settings.
The time required for a gain change is dominated by the settling
time of the amplifier. The AD8231 takes about 200 ns to switch
gains, after which the amplifier begins to settle. Refer to Figure 28
through Figure 32 to determine the settling time for different gains.
Table 7. Truth Table for AD8231 Gain Settings
CS
A2
A1
A0
Gain
Low
1
Low
High
2
Low
High
Low
4
Low
High
8
Low
High
Low
16
Low
High
Low
High
32
Low
High
Low
64
Low
High
128
High
X
No change
REFERENCE TERMINAL
The output voltage of the AD8231 is developed with respect to
the potential on the reference terminal, which is useful when
the output signal needs to be offset to a midsupply level. For
example, a voltage source can be tied to the REF pin to level-
shift the output so that the AD8231 can drive a single-supply
ADC. The REF pin is protected with ESD diodes and should
not exceed either +VS or VS by more than 0.3 V.
For best performance, source impedance to the REF terminal
should be kept below 1 Ω. As shown in Figure 49, the reference
terminal, REF, is at one end of a 14 kΩ resistor. Additional
impedance at the REF terminal adds to this 14 kΩ resistor
and results in amplification of the signal connected to the
positive input, causing a CMRR error.
INCORRECT
AD8231
IN-AMP
VREF
CORRECT
AD8231
IN-AMP
VREF
AD8231
OP AMP
+
–
+
–
+
–
06
58
6-
0
32
REF
Figure 50. Driving the Reference (REF)
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相关代理商/技术参数 |
参数描述 |
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| AD8231-EVALZ | 功能描述:BOARD EVAL FOR AD8231 RoHS:是 类别:编程器，开发系统 >> 评估板 - 运算放大器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:1 系列:- |
| AD8231TCPZ-EP-R7 | 功能描述:IC INSTR AMP PROGR ENH 16LFCSP RoHS:是 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 标准包装:150 系列:- 放大器类型:音频 电路数:2 输出类型:- 转换速率:5 V/µs 增益带宽积:12MHz -3db带宽:- 电流 - 输入偏压:100nA 电压 - 输入偏移:500µV 电流 - 电源:6mA 电流 - 输出 / 通道:50mA 电压 - 电源，单路/双路(±):4 V ~ 32 V，±2 V ~ 16 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-TSSOP（0.173"，4.40mm 宽） 供应商设备封装:8-TSSOP 包装:管件 |
| AD8231WACPZ-RL | 功能描述:IC AMP INST RRO 2.7MHZ 16LFCSP RoHS:是 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 标准包装:50 系列:LinCMOS™ 放大器类型:通用 电路数:4 输出类型:- 转换速率:0.05 V/µs 增益带宽积:110kHz -3db带宽:- 电流 - 输入偏压:0.7pA 电压 - 输入偏移:210µV 电流 - 电源:57µA 电流 - 输出 / 通道:30mA 电压 - 电源，单路/双路(±):3 V ~ 16 V，±1.5 V ~ 8 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:14-SOIC（0.154"，3.90mm 宽） 供应商设备封装:14-SOIC 包装:管件 产品目录页面:865 (CN2011-ZH PDF) 其它名称:296-1834296-1834-5 |
| AD8232 | 制造商:AD 制造商全称:Analog Devices 功能描述:Single-Lead, Heart Rate Monitor Front End |
| AD8232ACPZ | 制造商:AD 制造商全称:Analog Devices 功能描述:Single-Lead, Heart Rate Monitor Front End |
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