EL2244 Elantec Semiconductor, EL2244 Datasheet - Page 10

• Manufacturer Part Number: EL2244
• Description: Dual/Quad Low-Power 120MHz Unity-Gain Stable Op Amp
• Manufacturer: Elantec Semiconductor

EL2244C, EL2444C
Dual/Quad Low-Power 120MHz Unity-Gain Stable Op Amp
Applications Information
Product Description
The EL2244C/EL2444C are low-power wideband
monolithic operational amplifiers built on Elantec's pro-
prietary high-speed complementary bipolar process. The
EL2244C/EL2444C use a classical voltage-feedback
topology which allows them to be used in a variety of
applications where current-feedback amplifiers are not
appropriate because of restrictions placed upon the feed-
back element used with the amplifier. The conventional
topology of the EL2244C/EL2444C allows, for exam-
ple, a capacitor to be placed in the feedback path,
making it an excellent choice for applications such as
active filters, sample-and-holds, or integrators. Simi-
larly, because of the ability to use diodes in the feedback
network, the EL2244C/EL2444C are an excellent choice
for applications such as fast log amplifiers.
Power Dissipation
With the wide power supply range and large output drive
capability of the EL2244C/EL2444C, it is possible to
exceed the 150°C maximum junction temperatures
under certain load and power-supply conditions. It is
therefore important to calculate the maximum junction
temperature (T
power supply voltages, load conditions, or package type
need to be modified for the EL2244C/EL2444C to
remain in the safe operating area. These parameters are
related as follows:
T
where PDmaxtotal is the sum of the maximum power
dissipation of each amplifier in the package (PDmax).
PDmax for each amplifier can be calculated as follows:
PDmax= (2*V
where:
T
PDmax =Maximum Power Dissipation of 1 Amplifier
V
I
Smax
JA
Jmax
max
S
=Supply Voltage
=Thermal Resistance of the Package
=Maximum Ambient Temperature
=Maximum Supply Current of 1 Amplifier
= T
max
+ (
S
Jmax
*I
Smax
JA*
) for all applications to determine if
(PDmaxtotal))
+(V
S
-V
outmax
)*(V
outmax
/R
L
))
10
V
Application
R
To serve as a guide for the user, we can calculate maxi-
mum allowable supply voltages for the example of the
video cable-driver below since we know that T
150°C, T
ple) that we are driving a back-terminated video cable,
then the maximum average value (over duty-cycle) of
V
in Table 1.
Table 1
Single-Supply Operation
The EL2244C/EL2444C have been designed to have a
wide input and output voltage range. This design also
makes the EL2244C/EL2444C an excellent choice for
single-supply operation. Using a single positive supply,
the lower input voltage range is within 100mV of ground
(R
within 300 mV of ground. Upper input voltage range
reaches 4.2V, and output voltage range reaches 3.8V
with a 5V supply and R
output swing on a single 5V supply. This wide output
voltage range also allows single-supply operation with a
supply voltage as high as 36V or as low as 2.5V. On a
single 2.5V supply, the EL2244C/EL2444C still have
1V of output swing.
Gain-Bandwidth Product and the-3dB
Bandwidth
The EL2244C/EL2444C have a gain-bandwidth product
of 120 MHz while using only 5.2mA of supply current
per amplifier. For gains greater than 4, their closed-loop
-3 dB bandwidth is approximately equal to the gain-
EL2244CN
EL2244CS
QUADS
EL2444CN
EL2444CS
JA
L
outmax
outmax
L
=Load Resistance
s are shown in Table 1. If we assume (for this exam-
Duals
= 500 ), and the lower output voltage range is
is 1.4V, and R
=Maximum Output Voltage Swing of the
max
PDIP8
SO8
PDIP14
SO14
= 75°C, I
Package
L
Smax
L
95°C/W
150°C/W
70°C/W
110°C/W
= 150¾, giving the results seen
= 500 . This results in a 3.5V
JA
= 7.6mA, and the package
0.789W @ 75°C
0.500W @ 75°C
1.071W @ 75°C
0.682W @ 75°C
Max PDiss @ T
max
±16.6V
±10.7V
±11.5V
±7.5V
Max V
Jmax
S
=