參數(shù)資料
型號(hào)： AD8002ARZ-RL
廠商： Analog Devices Inc
文件頁(yè)數(shù)： 3/21頁(yè)
文件大?。?/td> 0K
描述： IC OPAMP CF DUAL LP LDIST 8SOIC
標(biāo)準(zhǔn)包裝： 2,500
放大器類型： 電流反饋
電路數(shù)： 2
轉(zhuǎn)換速率： 1200 V/µs
-3db帶寬： 600MHz
電流 - 輸入偏壓： 5µA
電壓 - 輸入偏移： 2000µV
電流 - 電源： 10mA
電流 - 輸出 / 通道： 70mA
電壓 - 電源，單路/雙路(±)： ±3 V ~ 6 V
工作溫度： -40°C ~ 85°C
安裝類型： 表面貼裝
封裝/外殼： 8-SOIC（0.154"，3.90mm 寬）
供應(yīng)商設(shè)備封裝： 8-SOIC
包裝： 帶卷 (TR)
REV. D
AD8002
–10–
THEORY OF OPERATION
A very simple analysis can put the operation of the AD8002, a
current feedback amplifier, in familiar terms. Being a current
feedback amplifier, the AD8002’s open-loop behavior is expressed
as transimpedance,
VO/I–IN, or TZ. The open-loop transim-
pedance behaves just as the open-loop voltage gain of a voltage
feedback amplifier, that is, it has a large dc value and decreases
at roughly 6 dB/octave in frequency.
Since the RIN is proportional to 1/gm, the equivalent voltage
gain is just TZ
× g
m, where the gm in question is the trans-
conductance of the input stage. This results in a low open-loop
input impedance at the inverting input, a now familiar result.
Using this amplifier as a follower with gain, Figure 4, basic
analysis yields the following result.
V
G
TS
G
R
G
R
Rg
O
IN
Z
ZIN
IN
m
=×
+×
+
=+
=
≈
()
/
1
2
150
VOUT
R1
R2
RIN
VIN
Figure 4.
Recognizing that G
× R
IN << R1 for low gains, it can be seen to
the first order that bandwidth for this amplifier is independent
of gain (G).
Considering that additional poles contribute excess phase at
high frequencies, there is a minimum feedback resistance below
which peaking or oscillation may result. This fact is used to
determine the optimum feedback resistance, R F. In practice
parasitic capacitance at the inverting input terminal will also add
phase in the feedback loop, so picking an optimum value for RF
can be difficult.
Achieving and maintaining gain flatness of better than 0.1 dB at
frequencies above 10 MHz requires careful consideration of
several issues.
Choice of Feedback and Gain Resistors
The fine scale gain flatness will, to some extent, vary with
feedback resistance. It, therefore, is recommended that once
optimum resistor values have been determined, 1% tolerance
values should be used if it is desired to maintain flatness over a
wide range of production lots. In addition, resistors of different
construction have different associated parasitic capacitance
and inductance. Surface mount resistors were used for the bulk
of the characterization for this data sheet. It is not recommended
that leaded components be used with the AD8002.
Printed Circuit Board Layout Considerations
As expected for a wideband amplifier, PC board parasitics can
affect the overall closed-loop performance. Of concern are
stray capacitances at the output and the inverting input nodes. If
a ground plane is to be used on the same side of the board as
the signal traces, a space (5 mm min) should be left around the
signal lines to minimize coupling. Additionally, signal lines
connecting the feedback and gain resistors should be short
enough so that their associated inductance does not cause high
frequency gain errors. Line lengths on the order of less than
5 mm are recommended. If long runs of coaxial cable are being
driven, dispersion and loss must be considered.
Power Supply Bypassing
Adequate power supply bypassing can be critical when optimiz-
ing the performance of a high-frequency circuit. Inductance in
the power supply leads can form resonant circuits that produce
peaking in the amplifier’s response. In addition, if large current
transients must be delivered to the load, bypass capacitors
(typically greater than 1
F) will be required to provide the
best settling time and lowest distortion. A parallel combina-
tion of 4.7
F and 0.1 F is recommended. Some brands of
electrolytic capacitors will require a small series damping resis-
tor
≈4.7 for optimum results.
DC Errors and Noise
There are three major noise and offset terms to consider in a
current feedback amplifier. For offset errors, refer to the equa-
tion below. For noise error, the terms are root-sum-squared to
give a net output error. In the circuit shown in Figure 5 they
are input offset (VIO), which appears at the output multiplied by
the noise gain of the circuit (1 + R F/RI), noninverting input
current (IBN
× RN), also multiplied by the noise gain, and the
inverting input current, which, when divided between RF and RI
and subsequently multiplied by the noise gain, always appears
at the output as IBN
× RF. The input voltage noise of the AD8002
is a low 2 nV/
√Hz. At low gains, though, the inverting input
current noise times RF is the dominant noise source. Careful
layout and device matching contribute to better offset and
drift specifications for the AD8002 compared to many other
current feedback amplifiers. The typical performance curves in
conjunction with the equations below can be used to predict the
performance of the AD8002 in any application.
VV
R
IR
R
IR
OUT
IO
F
I
BN
N
F
I
BI
F
=×
+
±×
×
+
±×
11
RF
RI
RN
IBN
VOUT
IBI
Figure 5. Output Offset Voltage
相關(guān)PDF資料
PDF描述
C22M2 FUSE INDUST 2A 690V CLASS AM
RMCF1206JT330K RES 330K OHM 1/4W 5% 1206 SMD
C22M6 FUSE INDUST 6A 690V CLASS AM
C22M12 FUSE INDUST 12A 690V CLASS AM
CS3014-FSZ IC OP AMP DUAL LOW NOISE 8-SOIC
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AD-800-2-N 制造商:Thomas & Betts 功能描述:
AD8003 制造商:AD 制造商全稱:Analog Devices 功能描述:Triple, 1.5 GHz Op Amp
AD80032KR 制造商:Analog Devices 功能描述:
AD80038JBC 制造商:Analog Devices 功能描述:
AD8003ACP-EBZ 功能描述:BOARD EVAL FOR AD8003ACP RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評(píng)估板 - 運(yùn)算放大器 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:-
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*