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參數(shù)資料
| 型號： | EL2357C |
| 英文描述： | 125 MHz Single Supply, Clamping Op Amps(125 MHz，單電源鉗位運算放大器) |
| 中文描述： | 125 MHz的單電源，夾緊運算放大器（125兆赫，單電源鉗位運算放大器） |
| 文件頁數(shù)： | 6/24頁 |
| 文件大?。?/td> | 518K |
| 代理商： | EL2357C |
EL2257CEL2357C
125 MHz Single Supply Clamping Op Amps
Applications Information
Contd
time domain and peaking in the frequency do-
main Therefore RF has some maximum value
which should not be exceeded for optimum per-
formance If a large value of RF must be used a
small capacitor in the few picofarad range in par-
allel with RF can help to reduce this ringing and
peaking at the expense of reducing the band-
width
As far as the output stage of the amplifier is con-
cerned RF a R G appear in parallel with RL for
gains other than a1 As this combination gets
smaller the bandwidth falls off Consequently
RF has a minimum value that should not be ex-
ceeded for optimum performance
For AV ea1 RF e 0X is optimum For AV e
b
1or a2 (noise gain of 2) optimum response is
obtained with RF between 500X and 1 kX For
AV eb4or a5 (noise gain of 5) keep RF be-
tween 2 k
X and 10 kX
Video Performance
For good video performance an amplifier is re-
quired to maintain the same output impedance
and the same frequency response as DC levels are
changed at the output This can be difficult when
driving a standard video load of 150
X because of
the change in output current with DC level Dif-
ferential Gain and Differential Phase for the
EL2257CEL2357C are specified with the black
level of the output video signal set to a12V
This allows ample room for the sync pulse even
in a gain of a2 configuration This results in dG
and dP specifications of 005% and 005 while
driving 150
X at a gain of a2 Setting the black
level to other values although acceptable will
compromise peak performance
For example
looking at the single supply dG and dP curves for
RLe150X if the output black level clamp is re-
duced from 12V to 06V dGdP will increase
from 005%005 to 008%025
Note that in a
gain of a2 configuration this is the lowest black
level allowed such that the sync tip doesn’t go
below 0V
If your application requires that the output goes
to
ground
then
the
output
stage
of
the
EL2257CEL2357C like all other single supply
op amps requires an external pull down resistor
tied to ground As mentioned above the current
flowing through this resistor becomes the DC
bias current for the output stage NPN transistor
As this current approaches zero the NPN turns
off and dG and dP will increase This becomes
more critical as the load resistor is increased in
value While driving a light load such as 1 k
X if
the input black level is kept above 125V dG and
dP are a respectable 003% and 003
For other biasing conditions see the Differential
Gain and Differential Phase vs Input Voltage
curves
Output Drive Capability
In spite of their moderately low 5 mA of supply
current the EL2257CEL2357C are capable of
providing g100 mA of output current into a 10
X
load or g60 mA into 50
X With this large output
current capability a 50
X load can be driven to
g
3V with VS e g5V making it an excellent
choice for driving isolation transformers in tele-
communications applications
Driving Cables and Capacitive Loads
When used as a cable driver double termination
is always recommended for reflection-free per-
formance For those applications the back-termi-
nation
series
resistor
will
de-couple
the
EL2257CEL2357C from the cable and allow ex-
tensive capacitive drive However other applica-
tions may have high capacitive loads without a
back-termination resistor In these applications a
small series resistor (usually between 5
X and
50
X) can be placed in series with the output to
eliminate most peaking The gain resistor (RG)
can then be chosen to make up for any gain loss
which may be created by this additional resistor
at the output
14
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PDF描述 |
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| EL2360C | Triple 130 MHz Current Feedback Amplifier |
| EL2360CN | Triple 130 MHz Current Feedback Amplifier |
| EL2360CS | Triple 130 MHz Current Feedback Amplifier |
| EL2386 | 250 MHz Triple Current Feedback Amp w/Disable |
| EL2386C | 250 MHz Triple Current Feedback Amp w/Disable |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| EL2357CN | 制造商:Rochester Electronics LLC 功能描述: 制造商:Intersil Corporation 功能描述: |
| EL2357CS | 制造商:ELANTEC 制造商全稱:ELANTEC 功能描述:125 MHz Single Supply, Clamping Op Amps |
| EL2357CS-02 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Intersil Corporation 功能描述: |
| EL2360 | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:Triple 130MHz Current Feedback Amplifier |
| EL2360C | 制造商:ELANTEC 制造商全稱:ELANTEC 功能描述:Triple 130 MHz Current Feedback Amplifier |
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