Precise Control of I/Q Modulator Output Power Using the ADL5386 Quadrature Modulator and the AD5621 12-Bit DAC

Application circuit provides up conversion of I/Q modulated data and automatic power control of the RF/IF carrier level. The output power is set by a 12-bit digital-to-analog converter (DAC) and can be precisely set over a linear-in-dB range of up to 30 dB. Stability over temperature is typically ±0.2 dB from -40 to +85 degree-C. It shows operation at an output frequency of 350 MHz, however the circuit operates from 50 MHz to 2.2. GHz