8

Applications Information

Product Description

The EL2244 and EL2444 are low-power wideband

monolithic operational amplifiers built on Elantec's

proprietary high-speed complementary bipolar process. The

EL2244 and EL2444 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 EL2244 and EL2444 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 EL2244

and EL2444 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 EL2244 and EL2444, it is possible to exceed

the 150°C maximum junction temperatures under certain

load and power-supply conditions. It is therefore important to

applications to determine if power supply voltages, load

conditions, or package type need to be modified for the

EL2244 and EL2444 to remain in the safe operating area.

These parameters are related as follows:

where:

amplifier can be calculated as follows:

where:

θ

application

To serve as a guide for the user, we can calculate maximum

allowable supply voltages for the example of the video

package

θ

example) that we are driving a back-terminated video cable,

then the maximum average value (over duty-cycle) of

Table 1.

Single-Supply Operation

The EL2244 and EL2444 have been designed to have a

wide input and output voltage range. This design also makes

the EL2244 and EL2444 an excellent choice for single-

supply operation. Using a single positive supply, the lower

ALL PACKAGES USE THE SAME SCHEMATIC

TABLE 1.

PART

PACKAGE

Θ

JA

MAX PDISS

DUALS

EL2244CN

PDIP8

100°C/W

0.650W @85°C

±16.6V

EL2244CS

SO8

160°C/W

0.406W @85°C

±10.5V

QUADS

EL2444CN

PDIP14

81°C/W

0.802W @85°C

±11.5V

EL2444CS

SO14

120°C/W

0.542W @85°C

±7.5V

T

JMAX

T

MAX

Θ

JA

PD

MAXTOTAL

×

()

+

=

PD

MAX

2V

S

I

SMAX

V

S

(

- V

V

OUTMAX

R

L

----------------------------

×

+

×

×

=

EL2244, EL2444