- 您現(xiàn)在的位置：買(mǎi)賣IC網(wǎng) > PDF目錄375244 > AD842 (Analog Devices, Inc.) Wideband, High Output Current,Fast Settling Op Amp(寬帶,高輸出電流,快速運(yùn)算放大器) PDF資料下載
參數(shù)資料
| 型號(hào)： | AD842 |
| 廠商： | Analog Devices, Inc. |
| 英文描述： | Wideband, High Output Current,Fast Settling Op Amp(寬帶,高輸出電流,快速運(yùn)算放大器) |
| 中文描述： | 寬帶，高輸出電流，快速沉降運(yùn)算放大器（寬帶，高輸出電流，快速運(yùn)算放大器） |
| 文件頁(yè)數(shù)： | 7/8頁(yè) |
| 文件大?。?/td> | 236K |
| 代理商： | AD842 |
AD842
REV. D
–7–
Figure 23. Settling Time Test Circuit
Figure 23 shows how measurement of the AD842’s 0.01% set-
tling in 100 ns was accomplished by amplifying the error signal
from a false summing junction with a very high-speed propri-
etary hybrid error amplifier specially designed to enable testing
of small settling errors. T he device under test was driving a
300
load. T he input to the error amp is clamped in order to
avoid possible problems associated with the overdrive recovery
of the oscilloscope input amplifier. T he error amp gains the er-
ror from the false summing junction by 15, and it contains a
gain vernier to fine trim the gain.
Figure 24 shows the “l(fā)ong term” stability of the settling charac-
teristics of the AD842 output after a 10 V step. T here is no evi-
dence of settling tails after the initial transient recovery time.
T he use of a junction isolated process, together with careful
layout, avoids these problems by minimizing the effects of tran-
sistor isolation capacitance discharge and thermally induced
shifts in circuit operating points. T hese problems do not occur
even under high output current conditions.
GROUNDING AND BY PASSING
In designing practical circuits with the AD842, the user must re-
member that whenever high frequencies are involved, some
Figure 24. AD842 Settling Demonstrating No Settling
Tails
special precautions are in order. Circuits must be built with
short interconnect leads. Large ground planes should be used
whenever possible to provide a low resistance, low inductance
circuit path, as well as minimizing the effects of high frequency
coupling. Sockets should be avoided because the increased
interlead capacitance can degrade bandwidth.
Feedback resistors should be of low enough value to assure that
the time constant formed with the circuit capacitances will not
limit the amplifier performance. Resistor values of less than
5 k
are recommended. If a larger resistor must be used, a small
(<10 pF) feedback capacitor connected in parallel with the feed-
back resistor, R
F
, may be used to compensate for these stray ca-
pacitances and optimize the dynamic performance of the
amplifier in the particular application.
Power supply leads should be bypassed to ground as close as
possible to the amplifier pins. A 2.2
μ
F capacitor in parallel with
a 0.1
μ
F ceramic disk capacitor is recommended.
CAPACIT IVE LOAD DRIVING ABILIT Y
Like all wideband amplifiers, the AD842 is sensitive to capaci-
tive loading. T he AD842 is designed to drive capacitive loads of
up to 20 pF without degradation of its rated performance. Ca-
pacitive loads of greater than 20 pF will decrease the dynamic
performance of the part although instability should not occur
unless the load exceeds 100 pF.
USING A HE AT SINK
T he AD842 draws less quiescent power than most precision
high speed amplifiers and is specified for operation without a
heat sink. However, when driving low impedance loads, the cur-
rent to the load can be 10 times the quiescent current. T his will
create a noticeable temperature rise. Improved performance can
be achieved by using a small heat sink such as the Aavid Engi-
neering #602B.
T E RMINAT E D LINE DRIVE R
T he AD842 is optimized for high speed line driver applications.
Figure 25 shows the AD842 driving a doubly terminated cable
in a gain-of-2 follower configuration. T he AD842 maintains a
typical slew rate of 375 V/
μ
s, which means it can drive a
±
10 V,
6.0 MHz signal or a
±
3 V, 19.9 MHz signal.
T he termination resistor, R
T
, (when equal to the characteristic
impedance of the cable) minimizes reflections from the far end
of the cable. A back-termination resistor (R
BT
, also equal to the
characteristic impedance of the cable) may be placed between
the AD842 output and the cable in order to damp any stray sig-
nals caused by a mismatch between R
T
and the cable’s charac-
teristic impedance. T his will result in a “cleaner” signal. With
this circuit, the voltage on the line equals V
IN
because one half
of V
OUT
is dropped across R
BT
.
T he AD842 has
±
100 mA minimum output current and, there-
fore, can drive
±
5 V into a 50
cable.
T he feedback resistors, R
1
and R
2
, must be chosen carefully.
Large value resistors are desirable in order to limit the amount
of current drawn from the amplifier output. But large resistors
can cause amplifier instability because the parallel resistance
R
1
i
R
2
combines with the input capacitance (typically 2–5 pF) to
create an additional pole. Also, the voltage noise of the AD842
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| AD8515 | 1.8 V Low Power CMOS Rail-to-Rail Input/Output Operational Amplifier |
| AD8515AKS | 1.8 V Low Power CMOS Rail-to-Rail Input/Output Operational Amplifier |
| AD8515ART | 1.8 V Low Power CMOS Rail-to-Rail Input/Output Operational Amplifier |
| AD8517 | 7 MHz Rail-to-Rail Low Voltage Operational Amplifiers |
| AD8517ART-REEL | 7 MHz Rail-to-Rail Low Voltage Operational Amplifiers |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AD8420 | 制造商:AD 制造商全稱:Analog Devices 功能描述:Low Noise, Low Gain Drift, G = 2000 |
| AD8420_12 | 制造商:AD 制造商全稱:Analog Devices 功能描述:Wide Supply Range, Micropower, |
| AD8420ARMZ | 功能描述:IC OP INSTR R-R MICROPWR 8-MSOP RoHS:是 類別:集成電路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 產(chǎn)品培訓(xùn)模塊:Differential Circuit Design Techniques for Communication Applications 標(biāo)準(zhǔn)包裝:1 系列:- 放大器類型:RF/IF 差分 電路數(shù):1 輸出類型:差分 轉(zhuǎn)換速率:9800 V/µs 增益帶寬積:- -3db帶寬:2.9GHz 電流 - 輸入偏壓:3µA 電壓 - 輸入偏移:- 電流 - 電源:40mA 電流 - 輸出 / 通道:- 電壓 - 電源，單路/雙路(±):3 V ~ 3.6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:16-VQFN 裸露焊盤(pán)，CSP 供應(yīng)商設(shè)備封裝:16-LFCSP-VQ 包裝:剪切帶 (CT) 產(chǎn)品目錄頁(yè)面:551 (CN2011-ZH PDF) 其它名稱:ADL5561ACPZ-R7CT |
| AD8420ARMZ_PROMO | 制造商:Analog Devices 功能描述:IC AMP INSTR RRO MSOP-8 |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。