參數(shù)資料
型號(hào): NCS2501
廠商: ON SEMICONDUCTOR
英文描述: 1.1mA 200MHz Current Feedback Op Amp with Enable Feature(1.1mA,200MHz電流反饋放大器)
中文描述: 一點(diǎn)一毫安200MHz的電流反饋運(yùn)算放大器與啟用功能(一點(diǎn)一毫安,200MHz的電流反饋放大器)
文件頁(yè)數(shù): 12/16頁(yè)
文件大?。?/td> 247K
代理商: NCS2501
NCS2501
http://onsemi.com
12
General Design Considerations
The current feedback amplifier is optimized for use in high
performance video and data acquisition systems. For current
feedback architecture, its closedloop bandwidth depends on
the value of the feedback resistor. The closedloop bandwidth
is not a strong function of gain, as is for a voltage feedback
amplifier, as shown in Figure 27.
Figure 27. Frequency Response vs. R
F
20
15
10
5
0
5
10
0.01
0.1
1.0
10
100
1000
10000
FREQUENCY (MHz)
G
R
F
= 1.8 k
R
F
= 1.2 k
R
F
= 1 k
A
V
= +2
V
CC
= +5 V
V
EE
= 5 V
The 3.0 dB bandwidth is, to some extent, dependent on the
power supply voltages. By using lower power supplies, the
bandwidth is reduced, because the internal capacitance
increases. Smaller values of feedback resistor can be used at
lower supply voltages, to compensate for this affect.
Feedback and Gain Resistor Selection for Optimum
Frequency Response
A current feedback operational amplifier’s key advantage
is the ability to maintain optimum frequency response
independent of gain by using appropriate values for the
feedback resistor. To obtain a very flat gain response, the
feedback resistor tolerance should be considered as well.
Resistor tolerance of 1% should be used for optimum flatness.
Normally, lowering RF resistor from its recommended value
will peak the frequency response and extend the bandwidth
while increasing the value of RF resistor will cause the
frequency response to roll off faster. Reducing the value of RF
resistor too far below its recommended value will cause
overshoot, ringing, and eventually oscillation.
Since each application is slightly different, it is worth some
experimentation to find the optimal RF for a given circuit. A
value of the feedback resistor that produces
peaking is the best compromise between stability and
maximal bandwidth. It is not recommended to use a current
feedback amplifier with the output shorted directly to the
inverting input.
0.1 dB of
Printed Circuit Board Layout Techniques
Proper high speed PCB design rules should be used for all
wideband amplifiers as the PCB parasitics can affect the
overall performance. Most important are stray capacitances at
the output and inverting input nodes as it can effect peaking
and bandwidth. A space (3/16
is plenty) should be left around
the signal lines to minimize coupling. Also, 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 less than 1/4
are
recommended.
Video Performance
This device designed to provide good performance with
NTSC, PAL, and HDTV video signals. Best performance is
obtained with back terminated loads as performance is
degraded as the load is increased. The back termination
reduces reflections from the transmission line and effectively
masks transmission line and other parasitic capacitances from
the amplifier output stage.
ESD Protection
This device is protected against electrostatic discharge
(ESD) on all pins as specified in the attributes table. Note:
Human Body Model for +IN and IN pins are rated at 0.8 kV
while all other pins are rated at 2.0 kV. Under closedloop
operation, the ESD diodes have no effect on circuit
performance. However, under certain conditions the ESD
diodes will be evident. If the device is driven into a slewing
condition, the ESD diodes will clamp large differential
voltages until the feedback loop restores closedloop
operation. Also, if the device is powered down and a large
input signal is applied, the ESD diodes will conduct.
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相關(guān)代理商/技術(shù)參數(shù)
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NCS2501D 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:1.1 mA 200 MHz Current Feedback Op Amp with Enable Feature
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NCS2501DR2G 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:1.1 mA 200 MHz Current Feedback Op Amp with Enable Feature
NCS2501SNT1 制造商:ONSEMI 制造商全稱:ON Semiconductor 功能描述:1.1 mA 200 MHz Current Feedback Op Amp with Enable Feature