DESCRIPTION
The LT®5502 is a 70MHz to 400MHz monolithic integrated quadrature IF demodulator. It consists of an IF limiter, quadrature down mixers, integrated lowpass filters, and divide-by-two LO buffers. The demodulator provides all building blocks for demodulation of I and Q baseband signals with a single supply voltage of 1.8V to 5.25V. The IF limiter has 84dB small-signal gain, and a built-in receive signal strength indicator (RSSI) with over 90dB linear range. The input referred noise-spectral-density is 1.45nV/√Hz, which is equivalent to a 4dB noise figure when the input is terminated with a 50Ω source. The integrated lowpass output filters act as antialiasing and pulse-shaping filters for demodulated I/Q-baseband signals.

FEATURES
■ Single 1.8V to 5.25V Supply
■ IF Frequency Range: 70MHz to 400MHz
■ 84dB Limiting IF Gain
■ 90dB Linear RSSI Range
■ 7.7MHz Lowpass Output Filter
■ Baseband I/Q Amplitude Imbalance: <0.7dB
■ 4dB Noise Figure
■ Low Supply Current: 25mA
■ Outputs Biased Up While in Standby
■ Shutdown Current: 1µA
■ 24-Lead Narrow SSOP Package

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