The EL4095 is a versatile variable-gain
building block. At its core is a fader
which can variably blend two inputs
together and an output amplifier that can drive heavy loads.
Each input appears as the input of a current-feedback
amplifier and with external resistors can separately provide
any gain desired. The output is defined as:
VOUT = A*VINA (0. 5V + VGAIN) + B*VINB (0.5V–VGAIN),
where A and B are the fed-back gains of each channel.
Additionally, two logic inputs are provided which each
override the analog VGAIN control and force 100% gain for
one input and 0% for the other. The logic inputs switch in
only 25ns and provide high attenuation to the off channel,
while generating very small glitches.
Signal bandwidth is 60MHz, and gain-control bandwidth
20MHz. The gain control recovers from overdrive in only
70ns.
The EL4095 operates from ±5V to ±15V power supplies, and
is available in both 14-pin DIP and narrow surface mount
packages.