EL5174, EL5374
Simplified Schematic
V
S
+
R
3
R
7
R
4
R
8
R
1
R
2
IN+
IN-
FBP
FBN
V
B1
OUT+
R
CD
R
CD
REF
R
9
R
10
C
C
V
B2
C
C
R
5
V
S
-
R
6
OUT-
Description of Operation and Application
Information
Product Description
The EL5174 and EL5374 are wide bandwidth, low power
and single/differential ended to differential output amplifiers.
The EL5174 is a single channel differential amplifier. Since
the I
N
- pin and REF pin are tired together internally, the
EL5174 can be used as a single ended to differential
converter. The EL5374 is a triple channel differential
amplifier. The EL5374 have a separate I
N
- pin and REF pin
for each channel. It can be used as single/differential ended
to differential converter. The EL5174 and EL5374 are
internally compensated for closed loop gain of +1 of greater.
Connected in gain of 1 and driving a 1kΩ differential load,
the EL5174 and EL5374 have a -3dB bandwidth of 550MHz.
Driving a 200Ω differential load at gain of 2, the bandwidth is
about 130MHz. The EL5374 is available with a power down
feature to reduce the power while the amplifier is disabled.
Differential and Common Mode Gain Settings
For EL5174, since the I
N
- pin and REF pin are bounded
together as the REF pin in an 8-pin 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
N
+ pin. For a ±5V supply, just tire the REF
pin to GND if the I
N
+ pin is biased at 0V with a 50Ω or 75Ω
termination resistor. For a single supply application, if the
I
N
+ is biased to half of the rail, the REF pin should be biased
to half of the rail also.
The gain setting for EL5174 is:
R
F1
+
R
F2
-
V
ODM
=
V
IN
+
×
1
+ ---------------------------
R
G
2R
F
-
V
ODM
=
V
IN
+
=
1
+ ----------
R
G
V
OCM
=
V
REF
=
0V
Input, Output, and Supply Voltage Range
The EL5174 and EL5374 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 EL5174 and EL5374 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.
Where:
V
REF
= 0V
R
F1
= R
F2
= R
F
EL5374 have a separate I
N
- pin and REF pin. It can be 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.
10
FN7313.5
August 8, 2005
INTERSIL [ INTERSIL CORPORATION ]
