EL2470CS ELANTEC [Elantec Semiconductor], EL2470CS Datasheet - Page 12

• Manufacturer Part Number: EL2470CS
• Description: 70 MHz/1 mA Current Mode Feedback Amplifiers
• Manufacturer: ELANTEC [Elantec Semiconductor]

Applications Information
Video Performance has also been measured with
a 500
tions the EL2170C EL2270C EL2470C have dG
and dP specifications of 0 01% and 0 02 respec-
tively while driving 500
Output Drive Capability
In spite of its low 1 mA of supply current the
EL2170C is capable of providing a minimum of
plifier of the EL2270C and the EL2470C is capa-
ble of providing a minimum of
output drive levels are unprecedented in amplifi-
ers running at these supply currents With a min-
imum
capable of driving 50
an excellent choice for driving isolation trans-
formers in telecommunications applications
Similarly the
each EL2270C and EL2470C amplifier allows
swings of
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 decouple the EL2170C
EL2270C EL2470C 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
50 ) can be placed in series with the output to
eliminate most peaking The gain resistor (R
can then be chosen to make up for any gain loss
which may be created by this additional resistor
at the output In many cases it is also possible to
simply increase the value of the feedback resistor
(R
g
EL2170C EL2270C EL2470C
70 MHz 1 mA Current Mode Feedback Amplifiers
80 mA of output current Similarly each am-
F
) to reduce the peaking
g
load at a gain of
80 mA of output drive the EL2170C is
g
2 5V into 50
g
50 mA minimum output drive of
loads to
a
loads
at A
1 Under these condi-
V
g
g
e a
50 mA These
4V making it
1
Contd
and
G
)
12
Current Limiting
The EL2170C EL2270C EL2470C have no inter-
nal current-limiting circuitry If any output is
shorted it is possible to exceed the Absolute
Maximum Ratings for output current or power
dissipation potentially resulting in the destruc-
tion of the device
Power Dissipation
With the high output drive capability of the
EL2170C EL2270C EL2470C it is possible to
exceed the 150 C Absolute Maximum junction
temperature under certain very high load current
conditions Generally speaking when R
low about 25
maximum junction temperature (T
application to determine if power-supply volt-
ages load conditions or package type need to be
modified for the EL2170C EL2270C EL2470C to
remain in the safe operating area These parame-
ters are calculated as follows
T
where
T
n
PD
PD
follows
PD
where
V
I
V
R
SMAX
JA
JMAX
MAX
S
OUTMAX
L
MAX
MAX
MAX
(V
S
e
e
for each amplifier can be calculated as
e
e
e
e
b
T
(2 V
e
e
e
e
Maximum Ambient Temperature
Thermal Resistance of the Package
Number of Amplifiers in the Pack-
age
Maximum Power Dissipation of
Each Amplifier in the Package
V
MAX
OUTMAX
Supply Voltage
Maximum Supply Current of 1
Amplifier
Max Output Voltage of the Ap-
plication
Load Resistance
it is important to calculate the
S
a
(
I
SMAX
JA
) (V
n PD
)
OUTMAX
a
MAX
JMAX
R
L
)
L
) for the
falls be-
))
1
2