9

FN7307.6

October 30, 2006

Simplified Schematic

Description of Operation and Application

Information

Product Description

The EL5171 and EL5371 are wide bandwidth, low power

and single ended to differential output amplifiers. The

EL5171 is a single channel differential amplifier. Since the

can be used as a single ended to differential converter. The

EL5371 is a triple channel differential amplifier. The EL5371

be used as single/differential ended to differential converter.

The EL5171 and EL5371 are internally compensated for

closed loop gain of +1 of greater. Connected in gain of 1 and

driving a 1k

Ω differential load, the EL5171 and EL5371 have

a -3dB bandwidth of 250MHz. Driving a 200

Ω differential

load at gain of 2, the bandwidth is about 30MHz. The

EL5371 is available with a power down feature to reduce the

power while the amplifier is disabled.

Input, Output, and Supply Voltage Range

The EL5171 and EL5371 have been designed to operate

with a single supply voltage of 5V to 10V or a split supplies

with its total voltage from 5V to 10V. The amplifiers have an

input common mode voltage range from -4.5V to 3.4V for

±5V supply. The differential mode input range (DMIR)

between the two inputs is from -2.3V to +2.3V. The input

voltage range at the REF pin is from -3.3V to 3.8V. If the

input common mode or differential mode signal is outside the

above-specified ranges, it will cause the output signal

distorted.

The output of the EL5171 and EL5371 can swing from -3.9V

to +3.9V at 1k

Ω differential load at ±5V supply. As the load

resistance becomes lower, the output swing is reduced.

Differential and Common Mode Gain Settings

together as the REF pin in an 8 Ld package, the signal at the

REF pin is part of the common mode signal and also part of

the differential mode signal. For the true balance differential

outputs, the REF pin must be tired to the same bias level as

to half of the rail, the REF pin should be biased to half of the

rail also.

The gain setting for EL5171 is:

Where:

as a single/differential ended to differential converter. The

voltage applied at REF pin can set the output common mode

voltage and the gain is one.

REF

OUT+

OUT-

FBN

FBP

IN-

IN+

+

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

+

⎝⎠

⎜⎟

⎛⎞

×

=

-----------

+

⎝⎠

⎜⎟

⎛⎞

×

=

=

=

EL5171, EL5371