The AD834 is a monolithic, laser-trimmed four-quadrant analog
multiplier intended for use in high frequency applications, with
a transconductance bandwidth (RL = 50 Ω) in excess of 500 MHz
from either of the differential voltage inputs. In multiplier
modes, the typical total full-scale error is 0.5%, dependent on
the application mode and the external circuitry. Performance
is relatively insensitive to temperature and supply variations due
to the use of stable biasing based on a band gap reference generator
and other design features.
To preserve the full bandwidth potential of the high speed bipolar
process used to fabricate the AD834, the outputs appear as a
differential pair of currents at open collectors. To provide a
single-ended ground referenced voltage output, some form of
external current-to-voltage conversion is needed. This may take
the form of a wideband transformer, balun, or active circuitry
such as an op amp. In some applications (such as power measure-
ment), the subsequent signal processing may not need to have
high bandwidth
