ADL5380, 400 MHz to 6 GHz Quadrature Demodulator

ADI's ADL5380 is a broadband quadrature I-Q demodulator that covers an RF / IF input frequency range from 400 MHz to 6 GHz. With a noise figure (NF) = 10.9 dB, input P1dB (IP1dB) = 11.6 dBm, and input IP3 (IIP3) = 29.7 dBm at 900 MHz, the ADL5380 demodulator offers outstanding dynamic range suitable for the demanding infrastructure direct-conversion requirements. The differential RF inputs provide a well-behaved broadband input impedance of 50 Ω and are best driven from a 1:1 balun for optimum performance.

Excellent demodulation accuracy is achieved with amplitude and phase balances of ~0.07 dB and ~0.2°, respectively. The demodulated in-phase (I) and quadrature (Q) differential outputs are fully buffered and provide a voltage conversion gain of ~7 dB. The buffered baseband outputs are capable of driving a 2 V_pp differential signal into 200 Ω.

The fully balanced design minimizes effects from second-order distortion. The leakage from the LO port to the RF port is <-50 dBm. Differential dc offsets at the I and Q outputs are typically <20 mV. Both of these factors contribute to the excellent IIP2 specification, which is >65 dBm.

The ADL5380 operates off a single 4.75 V to 5.25 V supply. The supply current is adjustable by placing an external resistor from the ADJ pin to either the positive supply, V_S, (to increase supply current and improve IIP3) or to ground (which decreases supply current at the expense of IIP3).

The ADL5380 is fabricated using the Analog Devices, Inc., advanced silicon-germanium bipolar process and is available in a 24-lead exposed paddle LFCSP.