EL2445 INTERSIL [Intersil Corporation], EL2445 Datasheet - Page 9

• Manufacturer Part Number: EL2445
• Description: Dual/Quad Low-Power 100MHz Gain-of-2 Stable Op Amp
• Manufacturer: INTERSIL [Intersil Corporation]

Burn-In Circuit
Applications Information
Product Description
The EL2245 and EL2445 are dual and quad low-power
wideband monolithic operational amplifiers built on Elantec's
proprietary high-speed complementary bipolar process. The
EL2245 and EL2445 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
feedback element used with the amplifier. The conventional
topology of the EL2245 and EL2445 allows, for example, 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. Similarly, because of the
ability to use diodes in the feedback network, the EL2245
and EL2445 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 EL2245 and EL2445, 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
applications to determine if power supply voltages, load
conditions, or package type need to be modified for the
EL2245 and EL2445 to remain in the safe operating area.
These parameters are related as follows:
where:
PD
of each amplifier in the package (PD
amplifier can be calculated as follows:
MAXTOTAL
PD
MAX
ALL PACKAGES USE THE SAME SCHEMATIC
=
T
2
is the sum of the maximum power dissipation
JMAX
×
V
S
×
=
(Per Amplifier)
I
T
SMAX
MAX
+
+
9
(
(
Θ
V
S
JA
–
×
V
MAX
PD
OUTMAX
MAXTOTAL
). PDmax for each
)
×
JMAX
V
--------------------------- -
OUTMAX
)
R
) for all
EL2245, EL2445
L
where:
To serve as a guide for the user, we can calculate maximum
allowable supply voltages for the example of the video cable-
driver below since we know that T
85°C, I
are shown in Table 1. If we assume (for this example) that we
are driving a back-terminated video cable, then the
maximum average value (over duty-cycle) of V
1.4V, and R
Single-Supply Operation
The EL2245 and EL2445 have been designed to have a
wide input and output voltage range. This design also makes
the EL2245 and EL2445 an excellent choice for single-
supply operation. Using a single positive supply, the lower
input voltage range is within 100mV of ground (R
and the lower output voltage range is within 300mV of
ground. Upper input voltage range reaches 4.2V, and output
voltage range reaches 3.8V with a 5V supply and
R
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 EL2245 and
EL2445 still have 1V of output swing.
Gain-Bandwidth Product and the -3dB Bandwidth
The EL2245 and EL2445 have a bandwidth at gain-of-2 of
100MHz while using only 5.2mA of supply current per
amplifier. For gains greater than 4, their closed-loop -3dB
bandwidth is approximately equal to the gain-bandwidth
product divided by the noise gain of the circuit. For gains
less than 4, higher-order poles in the amplifiers' transfer
DUALS
EL2245CN
EL2245CS
QUADS
EL2445CN
EL2445CS
L
T
θ
PD
V
I
V
application
R
SMAX
JA
= 500Ω. This results in a 3.5V output swing on a single
PART
MAX
S
OUTMAX
L
MAX
= Load resistance
= Supply voltage
= Thermal resistance of the package
SMAX
= Maximum ambient temperature
= Maximum supply current of each amplifier
= Maximum power dissipation of each amplifier
L
= Maximum output voltage swing of the
= 7.6mA per amplifier, and the package θ
PACKAGE
= 150Ω, giving the results seen in Table 1.
PDIP14
PDIP8
SO14
SO8
100°C/W
160°C/W
120°C/W
TABLE 1.
81°C/W
Θ
JA
JMAX
0.650W @85°C
0.406W @85°C
0.802W @85°C
0.542W @85°C
MAX PDISS
@T
= 150°C, T
MAX
OUTMAX
L
= 500Ω),
MAX
MAX V
±16.6V
±10.5V
±11.5V
±7.5V
JA
is
=
s
S