RSSI OUTPUT (V) LT5502 400MHz Quadrature IF Demodulator with RSSI FEATURES DESCRIPTIO n Single 1.8V to 5.25V Supply The LT 5502 is a 70MHz to 400MHz monolithic integrated n IF Frequency Range: 70MHz to 400MHz quadrature IF demodulator. It consists of an IF limiter, n 84dB Limiting IF Gain quadrature down mixers, integrated lowpass filters, and n 90dB Linear RSSI Range divide-by-two LO buffers. The demodulator provides all n 7.7MHz Lowpass Output Filter building blocks for demodulation of I and Q baseband n Baseband I/Q Amplitude Imbalance: <0.7dB signals with a single supply voltage of 1.8V to 5.25V. The n 4dB Noise Figure IF limiter has 84dB small-signal gain, and a built-in receive n Low Supply Current: 25mA signal strength indicator (RSSI) with over 90dB linear n Outputs Biased Up While in Standby range. The input referred noise-spectral-density is n Shutdown Current: 1m A 1.45nV/ Hz, which is equivalent to a 4dB noise figure n 24-Lead Narrow SSOP Package 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 sig- U nals. The 3dB cutoff frequency of the filters is about APPLICATIO S 7.7MHz. The VCO frequency is required to be twice the desired operating frequency to provide quadrature local n IEEE802.11 oscillator (LO) signals to the mixers. The standby mode n High Speed Wireless LAN provides fast transient response to the receive mode with n Wireless Local Loop reduced supply current when the I/Q outputs are AC-coupled to a baseband chip. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIO I/Q Output Swing, RSSI Output vs IF Input Power 2V C2 C1 1200 1.2 1F 1nF C3 22nF + 1000 1.0 IF V CC + I OUT IF R1 INPUT 800 0.8 240 IF BASEBAND I OUT 90 DIFFERENTIAL + 2XLO + I/Q OUTPUTS Q OUT 600 0.6 2XLO 2 INPUT Q OUT 0 2XLO 400 0.4 LT5502 RSSI ENABLE EN C4 GND 1.8pF 200 0.2 85 70 55 40 25 10 5 5502 TA01a IF INPUT POWER (dBm) 5502 TA01b Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 1 DIFFERENTIAL OUTPUT SWING (mV ) P-P U ULT5502 UUW ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) TOP VIEW ORDER PART Power Supply Voltage ............................................ 5.5V + + I 1 24 Q OUT OUT NUMBER LO Input Power .................................................. 10dBm I 2 23 Q OUT OUT IF Input Power .................................................... 10dBm LT5502EGN GND 3 22 V CC Operating Ambient V 4 21 GND CC Temperature (Note 2) ..............................40 C to 85 C GND 5 20 GND + + Storage Temperature Range ................. 65 C to 150 C IF 6 19 2XLO IF 7 18 2XLO Lead Temperature (Soldering, 10 sec).................. 300 C GND 8 17 V CC Voltage on any Pin not to Exceed ............................. V CC GND 9 16 V CC EN 10 15 RSSI STBY 11 14 GND + IFt 12 13 IFt GN PACKAGE 24-LEAD NARROW PLASTIC SSOP T = 150 C, q = 85 C/W JMAX JA Consult factory for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS V = 3V, f = 570MHz, P = 10dBm, f = 280MHz, CC 2XLO 2XLO IF P = 50dBm, T = 25 C, unless otherwise noted. (Note 3) IF A SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS IF Input f Frequency Range 70 to 400 MHz IF 3dB Limiting Sensitivity 79 dBm Noise Figure Terminated 50W Source 4 dB DC Common Mode Voltage 2.6 V Demodulator I/Q Output I/Q Output Voltage Swing Differential 850 mV P-P I/Q Amplitude Mismatch 0.1 0.7 dB I/Q Phase Mismatch 0.6 DEG Output Driving Capability Differential C = 10pF 1.5 kW MAX DC Common Mode Voltage 1.84 V RSSI Linear Dynamic Range (Note 4) 3dB Linearity Error 90 dB Output Impedance 3.8 kW Output Voltage Input = 70dBm 0.27 0.41 0.54 V Output Voltage Input = 0dBm 0.8 1.01 1.2 V Output Voltage Slope Input from 70dBm to 0dBm 8.7 mV/dB Linearity Error Input from 70dBm to 0dBm 1 dB Baseband Lowpass Filter 3dB Cutoff Frequency 7.7 MHz Group Delay Ripple 16.4 ns 2 U WWW