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参数资料
| 型号： | EL2450C |
| 英文描述： | 125 MHz Single Supply Quad Op Amps(125 MHz，单电源四路运算放大器) |
| 中文描述： | 125 MHz的单电源四路运算放大器（125兆赫，单电源四路运算放大器） |
| 文件页数： | 4/18页 |
| 文件大小： | 469K |
| 代理商： | EL2450C |
12
EL2250C/EL2450C
125 MHz Single Supply Dual/Quad Op Amps
EL2250C/EL2450C
optimum performance. 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 bandwidth.
As far as the output stage of the amplifier is concerned,
RF + RG appear in parallel with RL for gains other than
+1. As this combination gets smaller, the bandwidth falls
off. Consequently, RF has a minimum value that should
not be exceeded for optimum performance.
For AV = +1, RF = 0 is optimum. For AV = -1 or +2
(noise gain of 2), optimum response is obtained with RF
between 500
and 1 k. For Av = -4 or +5 (noise gain
of 5), keep RF between 2 k and 10 k.
Video Performance
For good video performance, an amplifier is required to
maintain the same output impedance and the same fre-
quency response as DC levels are changed at the output.
This can be difficult when driving a standard video load
of 150
, because of the change in output current with
DC level. Differential Gain and Differential Phase for
the EL2250C/EL2450C are specified with the black
level of the output video signal set to +1.2V. This allows
ample room for the sync pulse even in a gain of +2 con-
figuration. This results in dG and dP specifications of
0.05% and 0.05
° while driving 150 at a gain of +2.
Setting the black level to other values, although accept-
able, will compromise peak performance. For example,
looking at the single supply dG and dP curves for
RL=150 , if the output black level clamp is reduced
from 1.2V to 0.6V dG/dP will increase from
0.05%/0.05
° to 0.08%/0.25° Note that in a gain of +2
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 EL2250C/EL2450C,
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
, if the input black level is kept above
1.25V, dG and dP are a respectable 0.03% and 0.03
°.
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 EL2250C/EL2450C are capable of providing
±100
mA of output current into a 10
load, or ±60 mA into
50
. With this large output current capability, a 50
load can be driven to
±3V with VS = ±5V, making it an
excellent choice for driving isolation transformers in
telecommunications applications.
Driving Cables and Capacitive Loads
When used as a cable driver, double termination is
always recommended for reflection-free performance.
For those applications, the back-termination series resis-
tor will de-couple the EL2250C/EL2450C from the
cable and allow extensive capacitive drive. However,
other applications may have high capacitive loads with-
out a back-termination resistor. In these applications, a
small series resistor (usually between 5
and 50 ) 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.
Video Sync Pulse Remover Application
All CMOS Analog to Digital Converters (A/Ds) have a
parasitic latch-up problem when subjected to negative
input voltage levels. Since the sync tip contains no use-
ful video information and it is a negative going pulse, we
can chop it off.
Figure 1 shows a unity gain connected amplifier A of an
EL2250C. Figure 2 shows the complete input video sig-
nal applied at the input, as well as the output signal with
the negative going sync pulse removed.
相关PDF资料 |
PDF描述 |
|---|---|
| EL2460CN | Dual/Quad 130 MHz Current Feedback Amplifiers |
| EL2460CS | Dual/Quad 130 MHz Current Feedback Amplifiers |
| EL2460C | Quad 130 MHz Current Feedback Amplifiers(130 MHz，四路电流反馈放大器) |
| EL2470CN | 70 MHz/1 mA Current Mode Feedback Amplifiers |
| EL2470CS | 70 MHz/1 mA Current Mode Feedback Amplifiers |
相关代理商/技术参数 |
参数描述 |
|---|---|
| EL2450CN | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:125MHz Single Supply Dual/Quad Op Amps |
| EL2450CS | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:125MHz Single Supply Dual/Quad Op Amps |
| EL2450CS-T13 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:125MHz Single Supply Dual/Quad Op Amps |
| EL2450CS-T7 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Intersil Corporation 功能描述: |
| EL2460 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Dual/Quad 130MHz Current Feedback Amplifiers |
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