参数资料
型号: AD8656ARZ
厂商: ANALOG DEVICES INC
元件分类: 运动控制电子
英文描述: Low Noise, Precision CMOS Amplifier
中文描述: DUAL OP-AMP, 550 uV OFFSET-MAX, 28 MHz BAND WIDTH, PDSO8
封装: LEAD FREE, MS-012AA, SOIC-8
文件页数: 18/20页
文件大小: 273K
代理商: AD8656ARZ
AD8655/AD8656
LAYOUT, GROUNDING, AND BYPASSING CONSIDERATIONS
POWER SUPPLY BYPASSING
Power supply pins can act as inputs for noise, so care must be
taken to apply a noise-free, stable dc voltage. The purpose of
bypass capacitors is to create low impedances from the supply
to ground at all frequencies, thereby shunting or filtering most
of the noise. Bypassing schemes are designed to minimize the
supply impedance at all frequencies with a parallel combination
of capacitors with values of 0.1 μF and 4.7 μF. Chip capacitors
of 0.1 μF (X7R or NPO) are critical and should be as close as
possible to the amplifier package. The 4.7 μF tantalum capacitor
is less critical for high frequency bypassing, and, in most cases,
only one is needed per board at the supply inputs.
Rev. A | Page 18 of 20
GROUNDING
A ground plane layer is important for densely packed PC
boards to minimize parasitic inductances. This minimizes
voltage drops with changes in current. However, an under-
standing of where the current flows in a circuit is critical to
implementing effective high speed circuit design. The length
of the current path is directly proportional to the magnitude
of parasitic inductances, and, therefore, the high frequency
impedance of the path. Large changes in currents in an
inductive ground return create unwanted voltage noise.
The length of the high frequency bypass capacitor leads is
critical, and, therefore, surface-mount capacitors are recom-
mended. A parasitic inductance in the bypass ground trace
works against the low impedance created by the bypass
capacitor. Because load currents flow from the supplies, the
ground for the load impedance should be at the same physical
location as the bypass capacitor grounds. For larger value
capacitors intended to be effective at lower frequencies, the
current return path distance is less critical.
LEAKAGE CURRENTS
Poor PC board layout, contaminants, and the board insulator
material can create leakage currents that are much larger than
the input bias current of the AD8655/AD8656. Any voltage
differential between the inputs and nearby traces creates leakage
currents through the PC board insulator, for example, 1 V/100
GΩ = 10 pA. Similarly, any contaminants on the board can
create significant leakage (skin oils are a common problem).
To significantly reduce leakage, put a guard ring (shield) around
the inputs and input leads that are driven to the same voltage
potential as the inputs. This ensures there is no voltage potential
between the inputs and the surrounding area to create any
leakage currents. To be effective, the guard ring must be driven
by a relatively low impedance source and should completely
surround the input leads on all sides, above and below, by using
a multilayer board.
The charge absorption of the insulator material itself can also
cause leakage currents. Minimizing the amount of material
between the input leads and the guard ring helps to reduce the
absorption. Also, using low absorption materials, such as
Teflon or ceramic, may be necessary in some instances.
相关PDF资料
PDF描述
AD8656ARZ-REEL Low Noise, Precision CMOS Amplifier
AD8656ARZ-REEL7 Low Noise, Precision CMOS Amplifier
AD8655 Low Noise, Precision CMOS Amplifier
AD8655ARMZ-R2 Low Noise, Precision CMOS Amplifier
AD8655ARMZ-REEL Low Noise, Precision CMOS Amplifier
相关代理商/技术参数
参数描述
AD8656ARZ-REEL 功能描述:IC OPAMP GP R-R CMOS 28MHZ 8SOIC RoHS:是 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:DigiTrim® 标准包装:2,500 系列:- 放大器类型:通用 电路数:1 输出类型:满摆幅 转换速率:0.11 V/µs 增益带宽积:350kHz -3db带宽:- 电流 - 输入偏压:4nA 电压 - 输入偏移:20µV 电流 - 电源:260µA 电流 - 输出 / 通道:20mA 电压 - 电源,单路/双路(±):2.7 V ~ 36 V,±1.35 V ~ 18 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-SOIC(0.154",3.90mm 宽) 供应商设备封装:8-SO 包装:带卷 (TR)
AD8656ARZ-REEL7 功能描述:IC OPAMP GP R-R CMOS 28MHZ 8SOIC RoHS:是 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:DigiTrim® 标准包装:2,500 系列:- 放大器类型:通用 电路数:1 输出类型:满摆幅 转换速率:0.11 V/µs 增益带宽积:350kHz -3db带宽:- 电流 - 输入偏压:4nA 电压 - 输入偏移:20µV 电流 - 电源:260µA 电流 - 输出 / 通道:20mA 电压 - 电源,单路/双路(±):2.7 V ~ 36 V,±1.35 V ~ 18 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-SOIC(0.154",3.90mm 宽) 供应商设备封装:8-SO 包装:带卷 (TR)
AD8656WARMZ-REEL 功能描述:IC OPAMP GP R-R CMOS 28MHZ 8MSOP RoHS:是 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:DigiTrim® 标准包装:1,000 系列:- 放大器类型:电压反馈 电路数:4 输出类型:满摆幅 转换速率:33 V/µs 增益带宽积:20MHz -3db带宽:30MHz 电流 - 输入偏压:2nA 电压 - 输入偏移:3000µV 电流 - 电源:2.5mA 电流 - 输出 / 通道:30mA 电压 - 电源,单路/双路(±):4.5 V ~ 16.5 V,±2.25 V ~ 8.25 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:带卷 (TR)
AD8657 制造商:AD 制造商全称:Analog Devices 功能描述:18 V, Precision, Micropower CMOS RRIO Operational Amplifier
AD8657_11 制造商:AD 制造商全称:Analog Devices 功能描述:18 V, Precision, Micropower CMOS RRIO Operational Amplifier