EL2210C/11C, EL2310C/11C, EL2410C/11C
EL2210C/11C, EL2310C/11C, EL2410C/11C
Low Cost, Dual, Triple and Quad Video Op Amps
Application Information
Product Description
The EL2210C, EL2310C, and EL2410C are dual, triple,
and quad operational amplifiers stable at a gain of 1. The
EL2211C, EL2311C, and EL2411C are dual, triple, and
quad operational amplifiers stable at a gain of 2. All six
are built on Elantec's proprietary complimentary process
and share the same voltage mode feedback topology.
This topology allows them to be used in a variety of
applications where current mode feedback amplifiers are
not appropriate because of restrictions placed on the
feedback elements. These products are especially
designed for applications where high bandwidth and
good video performance characteristics are desired but
the higher cost of more flexible and sophisticated prod-
ucts are prohibitive.
The negative swing can be increased by adding an exter-
nal resistor of appropriate value from the output to the
negative supply. The simplified block diagram shows an
820Ω external pull-down resistor. This resistor is in par-
allel with the internal 1250Ω resistor. This will increase
the negative swing to
1250
×
820
V
EE
= 150
÷
-------------------------- + 150
-
1250 + 820
Or -1.16V
Power Dissipation and Loading
Without any load and a 10V supply difference the power
dissipation is 70mW per amplifier. At 12V supply dif-
ference this increases to 105mW per amplifier. At 12V
this translates to a junction temperature rise above ambi-
ent of 33°C for the dual and 40°C for the quad amplifier.
When the amplifiers provide load current the power dis-
sipation can rapidly rise.
In ±5V operation each output can drive a grounded
150Ω load to more than 2V. This operating condition
will not exceed the maximum junction temperature limit
as long as the ambient temperature is below 85°C, the
device is soldered in place, and the extra pull-down
resistor is 820Ω or more.
If the load is connected to the most negative voltage
(ground in single supply operation) you can easily
exceed the absolute maximum die temperature. For
example the maximum die temperature should be
150°C. At a maximum expected ambient temperature of
85°C, the total allowable power dissipation for the SO8
package would be:
150 – 85-
P
D
= ----------------------- = 361mW
160°C/W
Power Supplies
These amplifiers are designed to work at a supply volt-
age difference of 10V to 12V. These amplifiers will
work on any combination of ± supplies. All electrical
characteristics are measured with ±5V supplies. Below
9V total supply voltage the amplifiers’ performance will
degrade dramatically. The quiescent current is a direct
function of total supply voltage. With a total supply volt-
age of 12V the quiescent supply current will increase
from a typical 6.8mA per amplifier to 10mA per
amplifier.
Output Swing vs Load
Please refer to the simplified block diagram. These
amplifiers provide an NPN pull-up transistor output and
a passive 1250Ω pull-down resistor to the most negative
supply. In an application where the load is connected to
V
S
- the output voltage can swing to within 200mV of
V
S
-. In split supply applications where the DC load is
connected to ground the negative swing is limited by the
voltage divider formed by the load, the internal 1250Ω
resistor and any external pull-down resistor. If R
L
were
150Ω then it and the 1250Ω internal resistor limit the
maximum negative swing to
150
-
V
EE
= --------------------------
1250 + 150
Or--0.53V
7
At 12V total supply voltage each amplifier draws a max-
imum of 10mA and dissipates 12V * 10mA = 120mW or
240mW for the dual amplifier. Which leaves 121mW of
increased power due to the load. If the load were 150Ω
connected to the most negative voltage and the maxi-
mum voltage out were V
S
- +1V the load current would
be 6.67mA. Then an extra 146mW ((12V - 1V) *
6.67mA * 2) would be dissipated in the EL2210C or
ELANTEC [ ELANTEC SEMICONDUCTOR ]
