50 MHz to 1000 MHz Quadrature Demodulator

The AD8348 is a broadband quadrature demodulator with an integrated intermediate frequency (IF), variable gain amplifier (VGA), and integrated baseband amplifiers. It is suitable for use in communications receivers, performing quadrature demodulation from IF directly to baseband frequencies. The baseband amplifiers are designed to interface directly with dual-channel ADCs, such as the AD9201, AD9283, and AD9218, for digitizing and post-processing.

The IF input signal is fed into two Gilbert cell mixers through an X-AMP® VGA. The IF VGA provides 44 dB of gain control. A precision gain control circuit sets a linear-in-decibel gain characteristic for the VGA and provides temperature compensation. The LO quadrature phase splitter employs a divide-by-2 frequency divider to achieve high quadrature accuracy and amplitude balance over the entire operating frequency range.

The AD8348 is fabricated on an advanced bipolar process, operating on a single 3 or 5 volt supply, packaged in space saving 28 lead thin shrunk small outline (TSSOP) package and fully specified over the –40 to +85 C temperature range

Samples AD8348ARU and evaluation boards AD8348-EVAL are available

OTHER MODULATOR/DEMODULATOR PRODUCTS

AD8345 250MHz – 1GHz RF/IF Modulator

AD8346 800MHz – 2.5GHz Modulator

AD8347 800MHz – 2.7GHz Demodulator

AD8349 700MHz – 2.7GHz Modulator

* 50 MHz – 1000 MHz RF input range

* Integrated 45 dB linear-in-dB VGA IF amplifier

* Integrated baseband output amplifiers

* Demodulation bandwidth 75 MHz

* Quadrature phase accuracy 0.5°

* Amplitude balance 0.25 dB