参数资料
型号: AD8656ARMZ-R2
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, MO-187AA, MSOP-8
文件页数: 16/20页
文件大小: 273K
代理商: AD8656ARMZ-R2
AD8655/AD8656
APPLICATIONS
INPUT OVERVOLTAGE PROTECTION
The internal protective circuitry of the AD8655/AD8656 allows
voltages exceeding the supply to be applied at the input. It is
recommended, however, not to apply voltages that exceed the
supplies by more than 0.3 V at either input of the amplifier. If a
higher input voltage is applied, series resistors should be used to
limit the current flowing into the inputs. The input current
should be limited to less than 5 mA.
Rev. A | Page 16 of 20
One simple technique for compensation is a snubber that
consists of a simple RC network. With this circuit in place,
output swing is maintained, and the amplifier is stable at all
gains.
Figure 57 shows the implementation of a snubber, which
reduces overshoot by more than 30% and eliminates ringing.
Using a snubber does not recover the loss of bandwidth
incurred from a heavy capacitive load.
TIME (2
μ
s/DIV)
V
S
= ±2.5V
A
V
= 1
C
L
= 500pF
0
V
The extremely low input bias current allows the use of larger
resistors, which allows the user to apply higher voltages at the
inputs. The use of these resistors adds thermal noise, which
contributes to the overall output voltage noise of the amplifier.
For example, a 10 kΩ resistor has less than 12.6 nV/√Hz of
thermal noise and less than 10 nV of error voltage at room
temperature.
INPUT CAPACITANCE
Along with bypassing and ground, high speed amplifiers can be
sensitive to parasitic capacitance between the inputs and ground.
For circuits with resistive feedback network, the total capacitance,
whether it is the source capacitance, stray capacitance on the
input pin, or the input capacitance of the amplifier, causes a
breakpoint in the noise gain of the circuit. As a result, a
capacitor must be added in parallel with the gain resistor to
obtain stability. The noise gain is a function of frequency and
peaks at the higher frequencies, assuming the feedback capaci-
tor is selected to make the second-order system critically
damped. A few picofarads of capacitance at the input reduce
the input impedance at high frequencies, which increases the
amplifier’s gain, causing peaking in the frequency response or
oscillations. With the AD8655/AD8656, additional input
damping is required for stability with capacitive loads greater
than 200 pF with direct input to output feedback. See the
Driving Capacitive Loads section.
Figure 56. Driving Heavy Capacitive Loads Without Compensation
V+
200
Ω
500pF
500pF
V–
V
CC
V
EE
200mV
+
0
+
Figure 57. Snubber Network
V
S
= ±2.5V
A
V
= 1
R
S
= 200
Ω
C
S
= 500pF
C
L
= 500pF
TIME (10
μ
s/DIV)
0
V
DRIVING CAPACITIVE LOADS
Although the AD8655/AD8656 can drive capacitive loads up to
500 pF without oscillating, a large amount of ringing is present
when operating the part with input frequencies above 100 kHz.
This is especially true when the amplifiers are configured in
positive unity gain (worst case). When such large capacitive
loads are required, the use of external compensation is highly
recommended. This reduces the overshoot and minimizes
ringing, which, in turn, improves the stability of the
AD8655/AD8656 when driving large capacitive loads.
Figure 58. Driving Heavy Capacitive Loads Using a Snubber Network
相关PDF资料
PDF描述
AD8656ARMZ-REEL Low Noise, Precision CMOS Amplifier
AD8656ARZ Low Noise, Precision CMOS Amplifier
AD8656ARZ-REEL Low Noise, Precision CMOS Amplifier
AD8656ARZ-REEL7 Low Noise, Precision CMOS Amplifier
AD8655 Low Noise, Precision CMOS Amplifier
相关代理商/技术参数
参数描述
AD8656ARMZ-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® 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
AD8656ARZ 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® 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
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)