The AD834 is a monolithic, laser-trimmed four-quadrant analog
multiplier intended for use in high-frequency applications, with
a transconductance bandwidth (RL = 50 W) 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 measurement)
the subsequent signal processing may not need to
have high bandwidth.
The transfer function is accurately trimmed such that when
X = Y = ±1 V, the differential output is ±4 mA. This absolute
calibration allows the outputs of two or more AD834s to be
summed with precisely equal weighting, independent of the
accuracy of the load circuit.
The AD834J is specified for use over the commercial temperature
range of 0∞C to 70∞C and is available in an 8-lead DIP package
and an 8-lead plastic SOIC package. AD834A is available in
cerdip and 8-lead plastic SOIC packages for operation over the
industrial temperature range of –40∞C to +85∞C. The AD834S/
D883B is specified for operation over the military temperature
range of –55∞C to +125∞C and is available in the 8-lead cerdip
package. S-grade chips are also available.