5秒后页面跳转
捷配首页

Datasheet > 放大器电路 > 运算放大器> AD645
AD645 PDF预览

AD645

更新时间： 2024-01-26 09:45:09
品牌 Logo 应用领域
亚德诺 - ADI 运算放大器
页数 文件大小 规格书
8页 441K
描述
Low Noise, Low Drift FET Op Amp

阅读下载

获取价格

AD645 技术参数

是否Rohs认证：不符合生命周期：Obsolete
零件包装代码：TO-99包装说明：HERMETIC SEALED, METAL CAN, HEADER, TO-99, 8 PIN
针数：8Reach Compliance Code：not_compliant
ECCN代码：EAR99HTS代码：8542.31.00.01
风险等级：5.84Is Samacsys：N
放大器类型：OPERATIONAL AMPLIFIER架构：VOLTAGE-FEEDBACK
最大平均偏置电流 (IIB)：0.000005 µA25C 时的最大偏置电流 (IIB)：0.000005 µA
最小共模抑制比：90 dB标称共模抑制比：110 dB
频率补偿：YES最大输入失调电压：500 µV
JESD-30 代码：O-MBCY-W8JESD-609代码：e0
低-偏置：YES低-失调：NO
负供电电压上限：-18 V标称负供电电压 (Vsup)：-15 V
功能数量：1端子数量：8
最高工作温度：125 °C最低工作温度：-55 °C
封装主体材料：METAL封装代码：TO-99
封装等效代码：CAN8,.2封装形状：ROUND
封装形式：CYLINDRICAL峰值回流温度（摄氏度）：NOT SPECIFIED
电源：+-15 V认证状态：Not Qualified
最小摆率：1 V/us标称压摆率：2 V/us
子类别：Operational Amplifier最大压摆率：3.5 mA
供电电压上限：18 V标称供电电压 (Vsup)：15 V
表面贴装：NO技术：FET
温度等级：MILITARY端子面层：Tin/Lead (Sn/Pb)
端子形式：WIRE端子位置：BOTTOM
处于峰值回流温度下的最长时间：NOT SPECIFIED标称均一增益带宽：2000 kHz
最小电压增益：500000Base Number Matches：1

AD645 数据手册

 浏览型号AD645的Datasheet PDF文件第2页浏览型号AD645的Datasheet PDF文件第3页浏览型号AD645的Datasheet PDF文件第4页浏览型号AD645的Datasheet PDF文件第5页浏览型号AD645的Datasheet PDF文件第6页浏览型号AD645的Datasheet PDF文件第8页 
AD645  
10pF  
Sources of noise in a typical preamp are shown in Figure 32.  
The total noise contribution is defined as:  
109  
Ω
2
2
Rf  
Rf  
1 + s (Cd ) Rd  
Rd 1 + s (Cf ) Rf  
2
en  
2
2
2
i
i
i
V
=
+
+
s
+
1 +  
GUARD  
n
f
OUT  
1 + s (Cf ) Rf  
2
OUTPUT  
AD645  
6
Figure 33, a spectral density versus frequency plot of each  
source’s noise contribution, shows that the bandwidth of the  
3
8
PHOTODIODE  
amplifier’s input voltage noise contribution is much greater than  
its signal bandwidth. In addition, capacitance at the summing  
junction results in a “peaking” of noise gain in this configura-  
tion. This effect can be substantial when large photodiodes with  
large shunt capacitances are used. Capacitor Cf sets the signal  
bandwidth and also limits the peak in the noise gain. Each  
source’s rms or root-sum-square contribution to noise is ob-  
tained by integrating the sum of the squares of all the noise  
sources and then by obtaining the square root of this sum. Mini-  
mizing the total area under these curves will optimize the  
preamplifier’s overall noise performance.  
FILTERED  
OUTPUT  
OPTIONAL 26Hz  
FILTER  
Figure 30. The AD645 Used as a Sensitive Preamplifier  
Preamplifier Applications  
The low input current and offset voltage levels of the AD645 to-  
gether with its low voltage noise make this amplifier an excellent  
choice for preamplifiers used in sensitive photodiode applica-  
tions. In a typical preamp circuit, shown in Figure 30, the out-  
put of the amplifier is equal to:  
Cf  
10pF  
Rf  
109  
Ω
V
OUT = ID (Rf) = Rp (P) Rf  
where:  
PHOTODIODE  
en  
ID = photodiode signal current (Amps)  
i
f
i
Rp = photodiode sensitivity (Amp/Watt)  
n
Rd  
iS  
iS  
Cd  
50pF  
OUTPUT  
Rf = the value of the feedback resistor, in ohms.  
P = light power incident to photodiode surface, in watts.  
An equivalent model for a photodiode and its dc error sources is  
shown in Figure 31. The amplifier’s input current, IB, will con-  
tribute an output voltage error which will be proportional to the  
value of the feedback resistor. The offset voltage error, VOS, will  
cause a “dark” current error due to the photodiode’s finite  
shunt resistance, Rd. The resulting output voltage error, VE, is  
equal to:  
Figure 32. Noise Contributions of Various Sources  
10µV  
i
& i  
f
s
SIGNAL BANDWIDTH  
1µV  
i
n
WITH FILTER  
NO FILTER  
VE = (1 + Rf/Rd) VOS + Rf IB  
A shunt resistance on the order of 109 ohms is typical for a  
small photodiode. Resistance Rd is a junction resistance which  
will typically drop by a factor of two for every 10°C rise in tem-  
perature. In the AD645, both the offset voltage and drift are  
low, this helps minimize these errors.  
100nV  
e
n
en  
10nV  
1
10  
100  
1k  
10k  
100k  
FREQUENCY – Hz  
Cf  
10pF  
Figure 33. Voltage Noise Spectral Density of the Circuit of  
Figure 32 With and Without an Output Filter  
Rf  
109  
Ω
PHOTODIODE  
VOS  
An output filter with a passband close to that of the signal can  
greatly improve the preamplifier’s signal to noise ratio. The pho-  
todiode preamplifier shown in Figure 32—without a bandpass  
filter—has a total output noise of 50 µV rms. Using a 26 Hz  
single pole output filter, the total output noise drops to 23 µV  
rms, a factor of 2 improvement with no loss in signal bandwidth.  
IB  
OUTPUT  
Cd  
50pF  
Rd  
ID  
Figure 31. A Photodiode Model Showing DC Error  
Sources  
Using a “T” Network  
A “T” network, shown in Figure 34, can be used to boost the ef-  
fective transimpedance of an I to V converter, for a given feed-  
back resistor value. Unfortunately, amplifier noise and offset  
voltage contributions are also amplified by the “T” network  
gain. A low noise, low offset voltage amplifier, such as the  
AD645, is needed for this type of application.  
Minimizing Noise Contributions  
The noise level limits the resolution obtainable from any pream-  
plifier. The total output voltage noise divided by the feedback  
resistance of the op amp defines the minimum detectable signal  
current. The minimum detectable current divided by the photo-  
diode sensitivity is the minimum detectable light power.  
REV. B  
–7–  
1...45678

下载PDF

与AD645相关器件

型号 品牌 描述 获取价格 数据表
AD6458 ADI GSM 3 V Receiver IF Subsystem

获取价格
AD6458ARS ADI GSM 3 V Receiver IF Subsystem

获取价格
AD6459 ADI GSM 3 V Receiver IF Subsystem

获取价格
AD6459ARS ADI GSM 3 V Receiver IF Subsystem

获取价格
AD6459ARS-REEL ADI IC SPECIALTY TELECOM CIRCUIT, PDSO20, PLASTIC, SSOP-20, Telecom IC:Other

获取价格
AD645A ADI Low Noise, Low Drift FET Op Amp

获取价格

与AD645相关文章

您还可以找


热门产品
PCB打样/小批量
铝基板
BOM智能配单
PCBA制造
钣金
精密CNC
模具注塑
薄膜开关
精选活动
PCBA打样特惠
四六层板品质升级
铝基板品质升级
一体化电子制造
DFM下载
服务支持
企业认证
产品展示
工厂展示
工艺能力
积分商城
关于捷配
捷配简介
企业文化
公司动态
人才招聘
联系我们
帮助中心
下单流程
付款流程
开票流程
常见问题
全球PCB制造服务专线 400-613-0088

工作时间：9:00-21:00

CEO邮箱：ceo@jiepei.com

投诉邮箱：tousu@jiepei.com

捷配网-微信公众号 微信公众号
捷配网-微信公众号 抖音公众号
资质认证：
合作快递：
支付方式：
Copyright © 2024 Jiepei.com Inc. All Rights Reserved. 版权所有:杭州捷配信息科技有限公司 浙公网安备 33010502006866号 浙ICP备10014259号-119 营业执照ICP证