The ADL5387 is a wideband quadratureI/Q demodulatorcovering the RF/IF input frequency range from 30 MHz to 2 GHz. At 450 MHz, its noise figure (NF) is 13.2 dB, IP1dB is 12.7 dBm, and the third-order intercept point (IIP3) is 32 dBm. Excellent dynamic range for demanding infrastructure direct conversion applications. The differential RF/IF input provides good 50 Ω wideband input impedance and should be driven by a 1:1 balun for best performance.
Local oscillator (LO) quadrature generation uses a two-way approach for ultra-wideband operation. With amplitude balance and phase balance of approximately 0.05 dB and 0.4?, respectively, excellent demodulation accuracy is achieved over a wide LO level range. The demodulated in-phase (I) and quadrature (Q) differential outputs are fully buffered to provide more than 4 dB of voltage conversion gain. The buffered baseband output drives a 2 V p-p differential signal into a 200 Ω load.
A fully balanced design greatly reduces the effects of second-order distortion. The leakage from the LO port to the RF port is less than −70 dBc. The differential dc offset voltage at the I and Q outputs is less than 10 mV. These factors give the device excellent IIP2 characteristics above 60 dBm.
The ADL5387 operates from a single 4.75 V to 5.25 V supply and regulates the supply current using an external resistor connected to ground from the BIAS pin.
The ADL5387 is fabricated using Analog Devices' advanced silicon-germanium bipolar process and is available in a 24-lead, exposed pad LFCSP package.
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