EL5378 INTERSIL [Intersil Corporation], EL5378 Datasheet - Page 12

• Manufacturer Part Number: EL5378
• Description: 700MHz Differential Twisted-Pair Drivers
• Manufacturer: INTERSIL [Intersil Corporation]

Simplified Schematic
Description of Operation and Application
Information
Product Description
The EL5178 and EL5378 are wide bandwidth, low power
and single/differential ended to differential output amplifiers.
The EL5178 is a single channel differential amplifier. Since
the I
EL5178 can be used as a single ended to differential
converter. The EL5378 is a triple channel differential
amplifier. The EL5378 have a separate I
for each channel. It can be used as single/differential ended
to differential converter. The EL5178 and EL5378 are
internally compensated for closed loop gain of 1 of greater.
Connected in gain of 2 and driving a 1kΩ differential load,
the EL5178 and EL5378 have a -3dB bandwidth of 700MHz.
Driving a 200Ω differential load at gain of 2, the bandwidth is
about 320MHz. The EL5378 is available with a power down
feature to reduce the power while the amplifier is disabled.
Input, Output, and Supply Voltage Range
The EL5178 and EL5378 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 -4.3V 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 3.7V. 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 EL5178 and EL5378 can swing from -3.8V
to +3.8V at 1kΩ differential load at ±5V supply. As the load
resistance becomes lower, the output swing is reduced.
N
- pin and REF pin are tired together internally, the
IN+
R
IN-
1
12
FBP
N
- pin and REF pin
V
FBN
R
S
2
+
C
C
EL5178, EL5378
R
R
3
5
R
7
V
S
-
R
R
R
8
4
6
Differential and Common Mode Gain Settings
For EL5178, since the I
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
the I
the I
resistor. For a single supply application, if the I
to half of the rail, the REF pin should be biased to half of the
rail also.
The gain setting for EL5178 is:
V
V
V
Where:
EL5378 have a separate I
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.
ODM
ODM
OCM
V
R
REF
F1
V
V
N
N
B1
B2
+ pin. For a ±5V supply, just tire the REF pin to GND if
+ pin is biased at 0V with a 50Ω or 75Ω termination
=
=
=
= R
= 0V
V
V
V
C
C
IN
IN
REF
F2
+
+
= R
×
×
=
⎛
⎜
⎝
⎛
⎜
⎝
1
1
0V
F
+
+
OUT+
OUT-
R
--------------------------- -
2R
---------- -
R
F1
G
F
R
R
R
N
⎞
⎟
⎠
CD
CD
+
G
- pin and REF pin are bounded
N
R
- pin and REF pin. It can be used
F2
R
⎞
⎟
⎠
9
R
10
REF
N
+ is biased
May 16, 2007
FN7491.3