参数资料
| 型号： | AD8551ARMZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 7/24页 |
| 文件大小： | 0K |
| 描述： | IC OPAMP CHOPPER R-R 30MA 8MSOP |
| 标准包装： | 50 |
| 放大器类型： | 断路器（零漂移） |
| 电路数： | 1 |
| 输出类型： | 满摆幅 |
| 转换速率： | 0.4 V/µs |
| 增益带宽积： | 1.5MHz |
| 电流 - 输入偏压： | 10pA |
| 电压 - 输入偏移： | 1000µV |
| 电流 - 电源： | 850µA |
| 电流 - 输出 / 通道： | 30mA |
| 电压 - 电源，单路/双路(±)： | 2.7 V ~ 5.5 V |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-TSSOP，8-MSOP（0.118"，3.00mm 宽） |
| 供应商设备封装： | 8-MSOP |
| 包装： | 管件 |
Data Sheet
AD8551/AD8552/AD8554
Rev. E | Page 15 of 24
Amplification Phase
When the φB switches close and the φA switches open for the
amplification phase, this offset voltage remains on CM1 and,
essentially, corrects any error from the nulling amplifier. The
voltage across CM1 is designated as VNA. Furthermore, VIN is
designated as the potential difference between the two inputs to
the primary amplifier, or VIN = (VIN+ VIN). Thus, the nulling
amplifier can be expressed as
[ ]
(
)
[ ]
t
V
B
t
V
t
V
A
t
V
NA
A
OSA
IN
A
OA
=
]
[
(3)
+
AB
BB
CM2
VIN+
VNB
CM1
VOA
–BA
VNA
ФB
ФA
AA
VOSA
ФB
ФA
VOUT
VIN–
01101-
051
Figure 51. Output Phase of the Amplifier
Because φA is now open and there is no place for CM1 to discharge,
the voltage (VNA), at the present time (t), is equal to the voltage
at the output of the nulling amp (VOA) at the time when φA was
closed. If the period of the autocorrection switching frequency is
labeled tS, then the amplifier switches between phases every 0.5 × tS.
Therefore, in the amplification phase
[ ]
=
S
NA
t
V
t
V
2
1
(4)
Substituting Equation 4 and Equation 2 into Equation 3 yields
[ ]
A
S
OSA
A
OSA
A
IN
A
OA
B
t
V
B
A
t
V
A
t
V
A
t
V
+
+
=
1
2
1
(5)
For the sake of simplification, assume that the autocorrection
frequency is much faster than any potential change in VOSA or
VOSB. This is a valid assumption because changes in offset voltage
are a function of temperature variation or long-term wear time,
both of which are much slower than the auto-zero clock frequency
of the AD855x. This effectively renders VOS time invariant;
therefore, Equation 5 can be rearranged and rewritten as
[ ]
(
)
A
OSA
A
OSA
A
IN
A
OA
B
V
B
A
V
B
A
t
V
A
t
V
+
+
=
1
(6)
or
[ ]
+
=
A
OSA
IN
A
OA
B
V
t
V
A
t
V
1
(7)
From these equations, the auto-zeroing action becomes evident.
Note the VOS term is reduced by a 1 + BA factor. This shows how
the nulling amplifier has greatly reduced its own offset voltage
error even before correcting the primary amplifier. This results
in the primary amplifier output voltage becoming the voltage at
the output of the AD855x amplifier. It is equal to
[ ]
(
)
NB
B
OSB
IN
B
OUT
V
B
V
t
V
A
t
V
+
=
(8)
In the amplification phase, VOA = VNB, so this can be rewritten as
[ ]
+
=
A
OSB
IN
A
B
OSB
B
IN
B
OUT
B
V
t
V
A
B
V
A
t
V
A
t
V
1
(9)
Combining terms,
[ ]
(
)
OSA
B
A
OSA
A
B
IN
OUT
V
A
B
V
B
A
B
A
t
V
t
V
+
=
1
(10)
The AD855x architecture is optimized in such a way that
AA = AB and BA = BB and BA >> 1
Also, the gain product of AABB is much greater than AB. These
allow Equation 10 to be simplified to
[ ]
(
)
OSB
OSA
A
IN
OUT
V
A
B
A
t
V
t
V
+
≈
(11)
Most obvious is the gain product of both the primary and nulling
amplifiers. This AABA term is what gives the AD855x its extremely
high open-loop gain. To understand how VOSA and VOSB relate to
the overall effective input offset voltage of the complete amplifier,
establish the generic amplifier equation of
(
)
EFF
OS
IN
OUT
V
k
V
,
+
×
=
(12)
where k is the open-loop gain of an amplifier and VOS, EFF is its
effective offset voltage.
Putting Equation 12 into the form of Equation 11 gives
[ ]
A
EFF
OS
A
IN
OUT
B
A
V
B
A
t
V
t
V
,
+
≈
(13)
Thus, it is evident that
A
OSB
OSA
EFF
OS
B
V
+
≈
,
(14)
The offset voltages of both the primary and nulling amplifiers
are reduced by the Gain Factor BA. This takes a typical input
offset voltage from several millivolts down to an effective input
offset voltage of submicrovolts. This autocorrection scheme is
the outstanding feature of the AD855x series that continues to
earn the reputation of being among the most precise amplifiers
available on the market.
相关PDF资料 |
PDF描述 |
|---|---|
| 15-24-7243 | CONN HEADER 24POS 4.2MM STR GOLD |
| CT0805M4G | VARISTOR 4.0VRMS 0805 SMD |
| OP113FSZ-REEL7 | IC OPAMP GP 3.4MHZ LN 40MA 8SOIC |
| CT0805K30G | VARISTOR 30VRMS 0805 SMD |
| 15-24-7183 | CONN HEADER 18POS 4.2MM STR GOLD |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AD8551ARMZ-R2 | 制造商:Analog Devices 功能描述:SP Amp Zero Drift Amplifier Single R-R I/O 5V 8-Pin MSOP T/R 制造商:Analog Devices 功能描述:Operational Amplifier (Op-Amp) IC 制造商:Analog Devices 功能描述:IC OP AMP R/R SINGLE 8MSOP |
| AD8551ARMZ-REEL | 功能描述:IC OPAMP CHOPPER R-R 30MA 8MSOP RoHS:是 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 产品培训模块:Differential Circuit Design Techniques for Communication Applications 标准包装:1 系列:- 放大器类型:RF/IF 差分 电路数:1 输出类型:差分 转换速率:9800 V/µs 增益带宽积:- -3db带宽:2.9GHz 电流 - 输入偏压:3µA 电压 - 输入偏移:- 电流 - 电源:40mA 电流 - 输出 / 通道:- 电压 - 电源，单路/双路(±):3 V ~ 3.6 V 工作温度:-40°C ~ 85°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 包装:剪切带 (CT) 产品目录页面:551 (CN2011-ZH PDF) 其它名称:ADL5561ACPZ-R7CT |
| AD8551AR-REEL | 制造商:Analog Devices 功能描述:SP Amp Zero Drift Amplifier Single R-R I/O 5V 8-Pin SOIC N T/R |
| AD8551AR-REEL7 | 制造商:Analog Devices 功能描述:SP Amp Zero Drift Amplifier Single R-R I/O 5V 8-Pin SOIC N T/R |
| AD8551ARZ | 功能描述:IC OPAMP CHOPPER R-R 30MA 8SOIC RoHS:是 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 产品培训模块:Differential Circuit Design Techniques for Communication Applications 标准包装:1 系列:- 放大器类型:RF/IF 差分 电路数:1 输出类型:差分 转换速率:9800 V/µs 增益带宽积:- -3db带宽:2.9GHz 电流 - 输入偏压:3µA 电压 - 输入偏移:- 电流 - 电源:40mA 电流 - 输出 / 通道:- 电压 - 电源，单路/双路(±):3 V ~ 3.6 V 工作温度:-40°C ~ 85°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 包装:剪切带 (CT) 产品目录页面:551 (CN2011-ZH PDF) 其它名称:ADL5561ACPZ-R7CT |
发布紧急采购，3分钟左右您将得到回复。