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参数资料
| 型号： | AD8051 |
| 厂商： | Analog Devices, Inc. |
| 英文描述： | Low Cost, High Speed Rail-to-Rail Amplifiers |
| 中文描述： | 低成本，高速轨到轨放大器 |
| 文件页数： | 13/16页 |
| 文件大小： | 267K |
| 代理商： | AD8051 |
–13–
AD8051/AD8052/AD8054
REV. B
problems caused by junction isolation. These features allow the
construction of high frequency, low distortion amplifiers with low
supply currents. This design uses a differential output input stage
to maximize bandwidth and headroom (see Figure 1). The smaller
signal swings required on the first stage outputs (nodes S1P, S1N)
reduce the effect of nonlinear currents due to junction capacitances
and improve the distortion performance. With this design har-
monic distortion of –80 dBc @ 1 MHz into 100
with V
OUT
=
2 V p-p (Gain = +1) on a single 5 V supply is achieved.
The inputs of the device can handle voltages from –0.2 V below
the negative rail to within 1 V of the positive rail. Exceeding
these values will not cause phase reversal; however, the input
ESD devices will begin to conduct if the input voltages exceed
the rails by greater than 0.5 V. During this overdrive condition,
the output stays at the rail.
The rail-to-rail output range of the AD8051/AD8052/AD8054
is provided by a complementary common-emitter output stage.
High output drive capability is provided by injecting all out-
put stage predriver currents directly into the bases of the output
devices Q8 and Q36. Biasing of Q8 and Q36 is accomplished by
I8 and I5, along with a common-mode feedback loop (not
shown). This circuit topology allows the AD8051/AD8052 to drive
45 mA of output current and the AD8054 to drive 30mA of out-
put current with the outputs within 0.5V of the supply rails.
I10
R39
V
EE
I2
I3
Q25
Q51
R23 R27
I9
Q36
I5
V
EE
C3
V
OUT
C9
I8
V
CC
I11
I7
R3
R21
R5
Q3
SIP
SIN
C7
V
EE
V
IN
N
V
IN
P
Q4
R15
R2
V
CC
R26
Q50
Q22
Q21
Q27
Q7
Q8
Q23
Q31
Q39
Q13
Q1
Q24
Q47
Q11
Q2
Q5
Q40
Figure 41. AD8051/AD8052 Simplified Schematic
APPLICATIONS
Layout Considerations
The specified high speed performance of the AD8051/AD8052/
AD8054 requires careful attention to board layout and compo-
nent selection. Proper RF design techniques and low-parasitic
component selection are necessary.
The PCB should have a ground plane covering all unused por-
tions of the component side of the board to provide a low im-
pedance path. The ground plane should be removed from the
area near the input pins to reduce the parasitic capacitance.
Chip capacitors should be used for the supply bypassing. One
end should be connected to the ground plane and the other
within 3 mm of each power pin. An additional large (4.7
μ
F to
10
μ
F) tantalum electrolytic capacitor should be connected in
parallel, but not necessarily so close, to supply current for fast,
large signal changes at the output.
The feedback resistor should be located close to the inverting
input pin in order to keep the parasitic capacitance at this node
to a minimum. Parasitic capacitance of less than 1 pF at the
inverting input can significantly affect high speed performance.
Stripline design techniques should be used for long signal traces
(greater than about 25 mm). These should be designed with a
characteristic impedance of 50
or 75
and be properly termi-
nated at each end.
Active Filters
Active filters at higher frequencies require wider bandwidth op
amps to work effectively. Excessive phase shift produced by
lower frequency op amps can significantly impact active filter
performance.
Figure 42 shows an example of a 2MHz biquad bandwidth
filter that uses three op amps of an AD8054. Such circuits are
sometimes used in medical ultrasound systems to lower the
noise bandwidth of the analog signal before A/D conversion.
Please note that the unused amplifiers’ inputs should be tied to
ground.
12
13
14
2
1
R1
3k
V
V
IN
R2
2k
V
C1
50pF
R3
2k
V
6
5
7
R6
1k
V
R5
2k
V
9
10
8
AD8054
AD8054
C2
50pF
V
OUT
R4
2k
V
3
AD8054
Figure 42. 2MHz Biquad Bandpass Filter Using AD8054
The frequency response of the circuit is shown in Figure 43.
FREQUENCY – Hz
10k
100M
100k
1M
10M
0
2
10
2
20
2
30
2
40
G
Figure 43. Frequency Response of 2MHz Bandpass
Biquad Filter
A/D and D/A Applications
Figure 44 is a schematic showing the AD8051 used as a driver
for an AD9201, a 10-bit 20 MSPS dual A/D converter. This
converter is designed to convert I and Q signals in communica-
tion systems. In this application, only the I channel is being
driven. The I channel is enabled by applying a logic HIGH to
SELECT, Pin 27.
The AD8051 is running from a dual supply and is configured
for a gain of +2. The input signal is terminated in 50
and
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相关代理商/技术参数 |
参数描述 |
|---|---|
| AD8051_06 | 制造商:AD 制造商全称:Analog Devices 功能描述:Low Cost, High Speed, Rail-to-Rail Amplifiers |
| AD8051_07 | 制造商:AD 制造商全称:Analog Devices 功能描述:Low Cost, High Speed, Rail-to-Rail Amplifiers |
| AD8051AR | 功能描述:IC OPAMP VF R-R LDIST LP 8SOIC RoHS:否 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 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) |
| AD8051AR-EBZ | 功能描述:BOARD EVAL FOR AD8051AR RoHS:是 类别:编程器，开发系统 >> 评估板 - 运算放大器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:1 系列:- |
| AD8051AR-REEL | 制造商:Analog Devices 功能描述:OP Amp Single Volt Fdbk R-R O/P ±6V/12V 8-Pin SOIC N T/R 制造商:Rochester Electronics LLC 功能描述:SOIC SINGLE 200MHZ L/C RAIL-TO-RAIL AMP - Tape and Reel |
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