LT5502

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: 1mA
24-Lead Narrow SSOP Package


Application

IEEE802.11
High Speed Wireless LAN
Wireless Local Loop


Pinout




Specifications

Power Supply Voltage ............................................ 5.5V
LO Input Power .................................................. 10dBm
IF Input Power .................................................... 10dBm
Operating Ambient
Temperature (Note 2) ..............................40°C to 85°C
Storage Temperature Range ................. 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
Voltage on any Pin not to Exceed ............................. VCC

Description

The LT®5502 is a 70MHz to 400MHz monolithic integrated quadrature IF demodulator. LT5502 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 of LT5502 referred noise-spectral-density is 1.45nV/ÖHz, which is equivalent to a 4dB noise figure
when the input is terminated with a 50W source. The integrated lowpass output filters act as antialiasing and
pulse-shaping filters for demodulated I/Q-baseband signals. The 3dB cutoff frequency of the filters is about
7.7MHz. The VCO frequency of LT5502 is required to be twice the desired operating frequency to provide quadrature local
oscillator (LO) signals to the mixers. The standby mode provides fast transient response to the receive mode with
reduced supply current when the I/Q outputs are AC-coupled to a baseband chip.