DESCRIPTION
The LT®5506 is a 40MHz to 500MHz monolithic integrated quadrature demodulator with variable gain amplifier (VGA), designed for low voltage operation. It supports standards that use a linear modulation format. The chip consists of a VGA, quadrature down-converting mixers and lowpass noise filters. The LO port consists of a divide-by-two stage and LO buffers. The IC provides all building blocks for IF down-conversion to I and Q baseband signals with a single supply voltage of 1.8V to 5.25V. The VGA gain has a linearin-dB relationship to the control input voltage.

FEATURES
■ Wide Range 1.8V to 5.25V Supply
■ Frequency Range: 40MHz to 500MHz
■ –4dB to 59dB Variable Power Gain
■ THD < 0.12% (–58dBc) at 800mVP-P Differential Output Level
■ 8.8MHz I/Q Lowpass Output Noise Filters
■ IF Overload Detector
■ Baseband I/Q Amplitude Imbalance: 0.2dB
■ Baseband I/Q Phase Imbalance: 0.6°
■ 6.8dB Noise Figure at Max Gain
■ Input IP3 at Low Gain: –0.5dBm
■ Low Supply Current: 27mA
■ Low Delay Shift Over Gain Control Range: 2ps/dB
■ Outputs Biased Up While in Standby
■ 16-Lead QFN 4mm x 4mm Package with Exposed Pad

APPLICATIONS
■ IEEE802.11
■ High Speed Wireless LAN
■ Wireless Local Loop