AD834

·High Speed Real Time Computation
·Wideband Modulation and Gain Control
·Signal Correlation and RF Power Measurement
·Voltage Controlled Filters and Oscillators
·Linear Keyers for High Resolution Television
·Wideband True RMS

The AD834 is a monolithic laser-trimmed four-quadrant analog multiplier intended for use in high frequency applications, having a transconductance bandwidth (R_L = 50 ) 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 bandgap 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 to +70 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 to +85. The AD834S/883B is specified for operation over the military temperature range of 55 to +125 and is available in the 8-lead cerdip package. S-Grade chips are also available.

Two application notes featuring the AD834 (AN-212 and AN-216) can now be obtained by calling 1-800-ANALOG-D. For additional applications circuits consult the AD811 data sheet.