EL4452C
Wideband Variable-Gain Amplifier with Gain of 10
Typical Performance Curves
Contd
Supply Current
vs Die Temperature
Applications Information
The EL4452 is a complete two-quadrant multipli-
er gain control with 50 MHz bandwidth It has
three sets of inputs a differential signal input
VIN a differential gain-controlling input VGAIN
and another differential input which is used to
complete a feedback loop with the output Here is
a typical connection
14-Pin Package
Power Dissipation vs
Ambient Temperature
4452 – 21
4452 – 22
4451-23
The gain of the feedback divider is H The trans-
fer function of the part is
VOUT e AO c (((VINa) b (VINb)) c ((VGAINa) b (VGAINb)) a
(VREF b VFB))
VFB is connected to VOUT through a feedback
network so VFB e H c VOUT AO is the open-
loop gain of the amplifier and is approximately
3300 The large value of AO drives
((VINa) b (VINb)) c ((VGAINa) b (VGAINb)) a (VREF b VFB)
x0
Rearranging and substituting for VFB
VOUT e (((VINa) b (VINb)) c ((VGAINa) b (VGAIN)) a VREF) H
or
VOUT e (VIN c VGAIN a VREF) H
7