EL2099C Ver la hoja de datos (PDF) - Elantec -> Intersil
Número de pieza
componentes Descripción
Fabricante
EL2099C Datasheet PDF : 16 Pages
| |||
EL2099C
Video Distribution Amplifier
Applications Information
Product Description
The EL2099C is a current mode feedback amplifi-
er that has high output current drive capability
It is built using Elantec’s proprietary dielectric
isolation process that produces NPN and PNP
complimentary transistors The high output cur-
rent can be useful to drive many standard video
loads in parallel as well as digital sync pulses
that are 8V or greater
aInput Resistor Value
A small value resistor located in the aInput lead
is necessary to keep the EL2099C from oscillat-
ing under certain conditions A 50X resistor is
recommended for all applications although
smaller values will work under some circum-
stances All tests listed in this datasheet are per-
formed with 50X in the aInput lead as well as
all typical performance curves The 50X resistor
along with the aInput bias current creates an
additional typical Offset Voltage of only 250 mV
at T e 25 C and a maximum of 1 25 mV over
temperature variations
Feedback Resistor Values
The EL2099C has been designed and specified
with RF e 510X and AV e a2 This value of
feedback resistor yields extremely flat frequency
response with little to no peaking However 3 dB
bandwidth is reduced somewhat because of this
Wider bandwidth at the expense of slight peak-
ing can be accomplished by reducing the value of
the feedback resistor For example at a gain of
a2 reducing the feedback resistor to 330X in-
creases the b3 dB bandwidth to 70 MHz with
3 dB of peaking Inversely larger values of feed-
back resistor will cause roll off to occur at a lower
frequency There is essentially no peaking with
RF l 510X
Power Supplies
The EL2099C may be operated with single or
split supplies as low as g5V (10V total) to as
high as g18V (36V total) Bandwidth and slew
rate are almost constant from VS e g10V to
g18V and decrease slightly as supplies are re-
duced to g5V as shown in the characteristic
curves It is not necessary to use equal value split
supplies For example b5V and b12V would be
fine for 0V to 1V video signals
Good power supply bypassing should be used to
reduce the risk of oscillation A 1 mF to 10 mF
tantalum capacitor in parallel with a 0 1 mF ce-
ramic capacitor is recommended for bypassing
each supply pin They should be kept as close as
possible to the device pins
Due to the internal construction of the TO-220
package the tab of the EL2099C is connected to
the VSb pin Therefore care must be taken to
avoid connecting the tab to the ground plane of
the system
Printed Circuit Board Layout
As with any high frequency device good printed
circuit board layout is necessary for optimum
performance Ground plane construction is high-
ly recommended Lead lengths should be as short
as possible For good AC performance parasitic
capacitances should be kept to a minimum espe-
cially at the inverting input which is sensitive to
stray capacitance This implies keeping the
ground plane away from this pin Metal film and
carbon resistors are both acceptable while use of
wire-wound resistors is not recommended be-
cause of their parasitic inductance Similarly ca-
pacitors should be low inductance for best per-
formance
Driving Cables and Capacitive Loads
The EL2099C was designed with driving multi-
ple coaxial cables in mind With 440 mA of out-
put drive and low output impedance driving six
75X double terminated coaxial cables to g11V
with one EL2099C is practical
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 decouple the EL2099C
from the capacitive cable and allow extensive ca-
pacitive drive For a discussion on some of the
other ways to drive cables see the application
section on driving cables in the EL2003 data
sheet
10
Share Link: 