30 MH TO 2 GH Quadrature Demodulator

The ADL5387 is a broadband quadrature I/Q demodulator that covers an RF/IF input frequency range from 30 MHz to 2 GHz. With a NF = 13.2 dB, IP1dB = 12.7 dBm, and IIP3 = 32 dBm @ 450 MHz, the ADL5387 demodulator offers outstanding dynamic range suitable for the demanding infrastructure direct-conversion requirements. The differential RF/IF inputs provide a well-behaved broadband input impedance of 50 Ω and are best driven from a 1:1 balun for optimum performance.

Ultrabroadband operation is achieved with a divide-by-2 method for local oscillator (LO) quadrature generation. Over a wide range of LO levels, excellent demodulation accuracy is achieved with amplitude and phase balances ~0.05 dB and ~0.4°, respectively. The demodulated in-phase (I) and quadrature (Q) differential outputs are fully buffered and provide a voltage conversion gain of >4 dB. The buffered baseband outputs are capable of driving a 2 Vp-p 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 <−70 dBc. Differential dc-offsets at the I and Q outputs are <10 mV. Both of these factors contribute to the excellent IIP2 specifications > 60 dBm.

The ADL5387 operates off a single 4.75 V to 5.25 V supply. The supply current is adjustable with an external resistor from the BIAS pin to ground.

The ADL5387 is fabricated using the Analog Devices, Inc. advanced silicon-germanium bipolar process and is available in a 24-lead exposed paddle LFCSP.

APPLICATIONS

* QAM/QPSK RF/IF demodulators

* W-CDMA/CDMA/CDMA2000/GSM

* Microwave point-to-(multi)point radios

* Broadband wireless and WiMAX

* Broadband CATVs

* Operating RF frequency

30 MHz to 2 GHz

* Voltage conversion gain > 4 dB

60 MHz to 4 GHz

* Input IP3: 31 dBm @ 900 MHz

* Input IP2: 62 dBm @ 900 MHz

* Input P1dB: 13 dBm @ 900 MHz

* Noise figure (NF)

12.0 dB @ 140 MHz

14.7 dB @ 900 MHz