EL5171 INTERSIL [Intersil Corporation], EL5171 Datasheet - Page 10

• Manufacturer Part Number: EL5171
• Description: 250MHz Differential Twisted-Pair Drivers
• Manufacturer: INTERSIL [Intersil Corporation]

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
I
can be used as a single-ended to differential converter. The
EL5371 is a triple channel differential amplifier. The EL5371
has a separate I
be used as a single/differential ended to differential
converter. The EL5171 and EL5371 are internally
compensated for closed loop gain of +1 or greater.
Connected in gain of 1 and driving a 1kΩ differential load,
the EL5171 and EL5371 have a -3dB bandwidth of 250MHz.
Driving a 200Ω 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 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 to become distorted.
The output of the EL5171 and EL5371 can swing from -3.9V
to +3.9V at 1kΩ differential load at ±5V supply. As the load
resistance becomes lower, the output swing is reduced.
Differential and Common Mode Gain Settings
For EL5171, since the I
as the REF pin in an 8 Ld package, the signal at the REF pin is
N
- pin and REF pin are tied together internally, the EL5171
N
- pin and REF pin for each channel. It can
IN+
N
- pin and REF pin are bound together
R
IN-
1
10
FBP
V
FBN
R
S
2
+
C
C
EL5171, EL5371
R
R
3
5
R
7
V
S
-
R
R
R
8
4
6
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 tied to the same bias level as the I
supply, just tie the REF pin to GND if the I
with a 50Ω or 75Ω termination resistor. For a single supply
application, if the I
should be biased to half of the rail also.
The gain setting for EL5171 is expressed in Equation 1:
V
V
V
Where:
• V
• R
The EL5371 has a separate I
used 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.
The gain setting for EL5371 is expressed in Equation 2:
V
V
V
Where:
• R
ODM
ODM
OCM
ODM
OCM
ODM
REF
F1
F1
V
V
B1
B2
=
=
=
= R
=
=
=
= R
= 0V
V
V
V
(
V
(
C
V
V
C
IN
IN
REF
F2
REF
F2
IN
IN
+
+
+ V
+ V
= R
= R
×
×
=
–
–
⎛
⎜
⎝
⎛
⎜
⎝
1
1
0V
F
F
N
IN
IN
+
+
+ is biased to half of the rail, the REF pin
OUT+
OUT-
R
--------------------------- -
2R
---------- -
- )
- )
R
F1
G
×
×
F
R
R
R
⎛
⎜
⎝
⎛
⎜
⎝
⎞
⎟
⎠
CD
CD
+
G
1
1
R
+
+
F2
2R
---------- -
R
--------------------------- -
N
R
R
⎞
⎟
⎠
F1
- pin and REF pin. It can be
G
F
9
R
⎞
⎟
⎠
+
G
R
F2
R
10
⎞
⎟
⎠
REF
N
+ pin is biased at 0V
N
+ pin. For a ±5V
August 10, 2010
(EQ. 1)
(EQ. 2)
FN7307.7