전자부품 데이터시트 검색엔진
  Korean  ▼
ALLDATASHEET.CO.KR

X  

AD8883B 데이터시트(PDF) 9 Page - Analog Devices

부품명 AD8883B
상세설명  60 MHz, 2000 V/us Monolithic Op Amp
Download  16 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
제조업체  AD [Analog Devices]
홈페이지  http://www.analog.com
Logo AD - Analog Devices

AD8883B 데이터시트(HTML) 9 Page - Analog Devices

Back Button AD8883B Datasheet HTML 5Page - Analog Devices AD8883B Datasheet HTML 6Page - Analog Devices AD8883B Datasheet HTML 7Page - Analog Devices AD8883B Datasheet HTML 8Page - Analog Devices AD8883B Datasheet HTML 9Page - Analog Devices AD8883B Datasheet HTML 10Page - Analog Devices AD8883B Datasheet HTML 11Page - Analog Devices AD8883B Datasheet HTML 12Page - Analog Devices AD8883B Datasheet HTML 13Page - Analog Devices Next Button
Zoom Inzoom in Zoom Outzoom out
 9 / 16 page
background image
REV. D
AD844
–9–
It is important to understand that the low input impedance at
the inverting input is locally generated, and does not depend on
feedback. This is very different from the “virtual ground” of a
conventional operational amplifier used in the current summing
mode which is essentially an open circuit until the loop settles.
In the AD844, transient current at the input does not cause
voltage spikes at the summing node while the amplifier is settling.
Furthermore, all of the transient current is delivered to the
slewing (TZ) node (Pin 5) via a short signal path (the grounded
base stages and the wideband current mirrors).
The current available to charge the capacitance (about 4.5 pF)
at TZ node, is always proportional to the input error current, and
the slew rate limitations associated with the large signal response
of op amps do not occur. For this reason, the rise and fall times
are almost independent of signal level. In practice, the input
current will eventually cause the mirrors to saturate. When using
± 15 V supplies, this occurs at about 10 mA (or ± 2200 V/µs).
Since signal currents are rarely this large, classical “slew rate”
limitations are absent.
This inherent advantage would be lost if the voltage follower
used to buffer the output were to have slew rate limitations. The
AD844 has been designed to avoid this problem, and as a result
the output buffer exhibits a clean large signal transient response,
free from anomalous effects arising from internal saturation.
Response as a Noninverting Amplifier
Since current feedback amplifiers are asymmetrical with regard
to their two inputs, performance will differ markedly in nonin-
verting and inverting modes. In noninverting modes, the large
signal high speed behavior of the AD844 deteriorates at low
gains because the biasing circuitry for the input system (not
shown in Figure 4) is not designed to provide high input voltage
slew rates.
However, good results can be obtained with some care. The
noninverting input will not tolerate a large transient input; it
must be kept below
±1 V for best results. Consequently this mode
is better suited to high gain applications (greater than
×10).
TPC 20 shows a noninverting amplifier with a gain of 10 and a
bandwidth of 30 MHz. The transient response is shown in
TPCs 23 and 24. To increase the bandwidth at higher gains, a
capacitor can be added across R2 whose value is approximately
the ratio of R1 and R2 times Ct.
Noninverting Gain of 100
The AD844 provides very clean pulse response at high nonin-
verting gains. Figure 5 shows a typical configuration providing a
gain of 100 with high input resistance. The feedback resistor is
kept as low as practicable to maximize bandwidth, and a peak-
ing capacitor (CPK) can optionally be added to further extend
the bandwidth. Figure 6 shows the small signal response with
CPK = 3 nF, RL = 500
Ω, and supply voltages of either ±5 V or
±15 V. Gain bandwidth products of up to 900 MHz can be achieved
in this way.
The offset voltage of the AD844 is laser trimmed to the 50
µV
level and exhibits very low drift. In practice, there is an addi-
tional offset term due to the bias current at the inverting input
(IBN) which flows in the feedback resistor (R1). This can option-
ally be nulled by the trimming potentiometer shown in Figure 5.
8
OFFSET
TRIM
CPK 3nF
20
4.99
4.7
499
0.22 F
0.22 F
RL
VIN
+VS
–VS
AD844
R1
R2
4.7
+
Figure 5. Noninverting Amplifier Gain = 100, Optional
Offset Trim Is Shown
FREQUENCY – Hz
46
16
100k
1M
10M
40
34
28
22
20M
VS = 15V
VS = 5V
Figure 6. AC Response for Gain = 100, Configuration
Shown in Figure 5
USING THE AD844
Board Layout
As with all high frequency circuits considerable care must be
used in the layout of the components surrounding the AD844.
A ground plane, to which the power supply decoupling capaci-
tors are connected by the shortest possible leads, is essential
to achieving clean pulse response. Even a continuous ground
plane will exhibit finite voltage drops between points on the
plane, and this must be kept in mind in selecting the grounding
points. Generally speaking, decoupling capacitors should be
taken to a point close to the load (or output connector) since
the load currents flow in these capacitors at high frequencies.
The +IN and –IN circuits (for example, a termination resistor
and Pin 3) must be taken to a common point on the ground
plane close to the amplifier package.
Use low impedance capacitors (AVX SR305C224KAA or
equivalent) of 0.22
µF wherever ac coupling is required. Include
either ferrite beads and/or a small series resistance (approxi-
mately 4.7
Ω) in each supply line.


유사한 부품 번호 - AD8883B

제조업체부품명데이터시트상세설명
logo
Analog Devices
AD880 AD-AD880 Datasheet
341Kb / 4P
   Optical Disk Servo/Data Channel Processing Element
AD8801 AD-AD8801 Datasheet
213Kb / 16P
   Octal 8-Bit TrimDAC with Power Shutdown
REV. A
AD8801AN AD-AD8801AN Datasheet
213Kb / 16P
   Octal 8-Bit TrimDAC with Power Shutdown
REV. A
AD8801AN AD-AD8801AN Datasheet
216Kb / 16P
   Octal 8-Bit TrimDAC with Power Shutdown
REV. A
AD8801AR AD-AD8801AR Datasheet
213Kb / 16P
   Octal 8-Bit TrimDAC with Power Shutdown
REV. A
More results

유사한 설명 - AD8883B

제조업체부품명데이터시트상세설명
logo
Analog Devices
AD844 AD-AD844 Datasheet
493Kb / 12P
   60 MHz, 2000 V/us Monolithic Op Amp
REV. C
AD844ANZ AD-AD844ANZ Datasheet
422Kb / 20P
   60 MHz 2000 V Monolithic Op Amp
Rev. F
AD844 AD-AD844_15 Datasheet
422Kb / 20P
   60 MHz 2000 V/s Monolithic Op Amp
Rev. F
logo
Texas Instruments
TLV9051 TI1-TLV9051_19 Datasheet
2Mb / 50P
[Old version datasheet]   5-MHz, 15-V/us high slew-rate, RRIO op amp
logo
Linear Technology
LT1357 LINER-LT1357 Datasheet
288Kb / 12P
   25MHz, 600V/us Op Amp
logo
Analog Devices
AD846 AD-AD846 Datasheet
513Kb / 12P
   450 V/us, Precision, Current-Feedback Op Amp
REV. C
logo
Linear Technology
LT1354 LINER-LT1354 Datasheet
296Kb / 12P
   12MHz, 400V/us Op Amp
LT1363 LINER-LT1363 Datasheet
251Kb / 12P
   70MHz, 1000V/us Op Amp
LT1360 LINER-LT1360 Datasheet
263Kb / 16P
   50MHz, 800V/us Op Amp
logo
National Semiconductor ...
CLC415 NSC-CLC415 Datasheet
338Kb / 6P
   Quad, Wideband Monolithic Op Amp
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16


데이터시트 다운로드

Go To PDF Page


링크 URL




개인정보취급방침
ALLDATASHEET.CO.KR
ALLDATASHEET 가 귀하에 도움이 되셨나요?  [ DONATE ] 

Alldatasheet는?   |   광고문의   |   운영자에게 연락하기   |   개인정보취급방침   |   링크교환   |   제조사별 검색
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com