LT5502 LINER
Document overview
- Manufacturer or author: Provided By www.digicamel.com(FREE DATASHEET DOWNLOAD SITE)
- PDF pages: 12
Technical content
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. Final Electrical Specifications n IEEE802.11 n High Speed Wireless LAN n Wireless Local Loop n Single 1.8V to 5.25V Supply n IF Frequency Range: 70MHz to 400MHz n 84dB Limiting IF Gain n 90dB Linear RSSI Range n 7.7MHz Lowpass Output Filter n Baseband I/Q Amplitude Imbalance: <0.7dB n 4dB Noise Figure n Low Supply Current: 25mA n Outputs Biased Up While in Standby n Shutdown Current: 1mA n 24-Lead Narrow SSOP Package APPLICATIO SU FEATURES DESCRIPTIO U TYPICAL APPLICATIO U 400MHz Quadrature IF Demodulator with RSSI January 2001 , LTC and LT are registered trademarks of Linear Technology Corporation. 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/ÖHz, which is equivalent to a 4dB noise figure when the input is terminated with a 50 W source. The integrated lowpass output filters act as antialiasing and pulse-shaping filters for demodulated I/Q-baseband sig- nals. The 3dB cutoff frequency of the filters is about 7.7MHz. The VCO frequency 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. I/Q Output Swing, RSSI Output vs IF Input Power IF INPUT POWER (dBm) –85 DIFFERENTIAL OUTPUT SWING (mVP-P) 1200 1000 800 600 400 200 RSSI OUTPUT (V) 1.2 1.0 0.8 0.6 0.4 0.2 –70 –55 –40 –25
5502 TA01b
–10 5 2XLO+ 2XLO– IF+ IF– EN VCC IOUT+ IOUT– QOUT+ QOUT– 90° GND 1µF 1nF 1.8pF RSSI ENABLE 2XLO INPUT IF INPUT 240Ω 22nF BASEBAND DIFFERENTIAL I/Q OUTPUTS
5502 TA01a
TJMAX = 150°C, qJA = 85°C/W LT5502EGN ABSOLUTE AXI U RATI GSW WW U PACKAGE/ORDER I FOR ATIOUU W (Note 1) ELECTRICAL CHARACTERISTICSVCC = 3V, f2XLO = 570MHz, P2XLO = –10dBm, f IF = 280MHz, PIF = –50dBm, TA = 25°C, unless otherwise noted. (Note 3) Consult factory for parts specified with wider operating temperature ranges. TOP VIEW GN PACKAGE 24-LEAD NARROW PLASTIC SSOP Q OUT+ QOUT– VCC GND GND 2XLO 2XLO– VCC VCC RSSI GND IFt IOUT+ IOUT– GND VCC GND IF+ IF– GND GND EN STBY IFt SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS IF Input fIF Frequency Range 70 to 400 MHz 3dB Limiting Sensitivity –79 dBm Noise Figure Terminated 50 W 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 MAX = 10pF 1.5 k W DC Common Mode Voltage 1.84 V RSSI Linear Dynamic Range (Note 4) –3dB Linearity Error 90 dB Output Impedance 3.8 k W 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
TYPICAL PERFOR A CE CHARACTERISTICSUW Power Supply Current vs Temperature I/Q Output Swing vs Temperature I/Q Output Swing vs IF Input Power ELECTRICAL CHARACTERISTICSVCC = 3V, f2XLO = 570MHz, P2XLO = –10dBm, f IF = 280MHz, PIF = –50dBm, TA = 25°C, unless otherwise noted. (Note 3) (Note 3) IF INPUT POWER (dBm) –85 DIFFERENTIAL OUTPUT SWING (mVP-P)
5502 G03
TA = –40°C TA = 25°C TA = 85°C VCC = 3V fIF = 280MHz SUPPLY VOLTAGE (V) 1.8 SUPPLY CURRENT (mA) 5.5
5502 G01
2.5 3.5 4.5 TA = –40°C TA = 25°C TA = 85°C SUPPLY VOLTAGE (V) 1.8 DIFFERENTIAL OUTPUT SWING (mVP-P) 800 1000 5.5
5502 G02
2.5 3.5 4.5 1200 TA = –40°C TA = 25°C TA = 85°C fIF = 280MHz SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS 2XLO f2XLO Frequency Range 140 to 800 MHz P2XLO Input Power –20 –5 dBm DC Common Mode Voltage 2.6 V Power Supply VCC Supply Voltage 1.8 5.25 V ICC Supply Current EN = High 25 32 mA IOFF Shutdown Current EN = Low; Standby = Low 1 100 mA Standby Mode Current EN = Low; Standby = High 2.6 3.5 mA Note 1: Absolute Maximum Ratings are those values beyond which the life a device may be impaired. Note 2: Specifications over the –40°C to 85°C temperature range are assured by design, characterization and correlation with statistical process controls. Note 3: Tests are performed as shown in the configuration of Figure 3. Note 4: Tests are performed as shown in the configuration of Figure 1 for IF input.
RSSI Output Voltage vs VCC IF Input Sensitivity vs Temperature IF Input Sensitivity vs IF Frequency TYPICAL PERFOR A CE CHARACTERISTICSUW LPF Frequency Response vs Baseband Frequency LPF Group Delay vs Baseband Frequency LPF Frequency Response vs VCC (Note 3) IF INPUT POWER (dBm) –85 RSSI OUTPUT (V)
5502 G07
1.2 1.0 0.8 0.6 0.4 0.2 fIF = 280MHz TA = 25°C VCC = 3V VCC = 5.5V VCC = 1.8V SUPPLY VOLTAGE (V) 1.8 INPUT SENSITIVITY (dBm) 5.5
5502 G08
2.5 3.5 4.5 –73 –75 –77 –79 –81 –83 TA = –40°C TA = 25°C TA = 85°C fIF = 280MHz IF FREQUENCY (MHz) INPUT SENSITIVITY (dBm) –79 –76
5502 G09
–82 –85 150 200 250 300 350 400100 –73 TA = –40°CTA = 25°C VCC = 3V TA = 85°C BASEBAND FREQUENCY (MHz) GAIN RESPONSE (dB) 12 20
5502 G10
–10 –15 –20 –25 –30 –35 VCC = 3V TA = 85°C TA = –40°C TA = 25°C BASEBAND FREQUENCY (MHz) GROUP DELAY (ns) 110 4 8 12 16
5502 G11
VCC = 3V TA = 85°C TA = –40°C TA = 25°C BASEBAND FREQUENCY (MHz) GAIN RESPONSE (dB) 12 20
5502 G12
–10 –15 –20 –25 –30 –35 110 VCC = 1.8V, 3V, 5.5V TA = 25°C GROUP DELAY (ns) I/Q Output Swing vs IF Input Power RSSI Output vs Temperature RSSI Output Voltage vs IF Frequency IF INPUT POWER (dBm) –85 DIFFERENTIAL OUTPUT SWING (mVP-P)
5502 G04
fIF = 70MHz fIF = 280MHz fIF = 400MHz VCC = 3V TA = 25°C IF INPUT POWER (dBm) –85 RSSI OUTPUT (V)
5502 G05
1.2 1.0 0.8 0.6 0.4 0.2 TA = –40°C TA = 85°C VCC = 3V fIF = 280MHz TA = 25°C IF INPUT POWER (dBm) –85 RSSI OUTPUT (V)
5502 G06
1.2 1.0 0.8 0.6 0.4 0.2 fIF = 70MHz fIF = 280MHz VCC = 3V TA = 25°C fIF = 400MHz
IOUT+ (Pin 1): Positive Baseband Output Pin of I-Channel. The DC bias voltage is VCC – 1.16V. This pin should not be shorted to ground. IOUT– (Pin 2): Negative Baseband Input Pin of I-Channel. The DC bias voltage is VCC – 1.16V. This pin should not be shorted to ground. GND (Pins 3, 5, 8, 9, 14, 20, 21): Ground Pin. VCC (Pins 4, 16, 17, 22): Power Supply Pin. This pin should be decoupled using 1000pF and 0.1mF capacitors. IF+ (Pin 6): Positive IF Input Pin. The DC bias voltage is VCC – 0.4V. IF– (Pin 7): Negative IF Input Pin. The DC bias voltage is VCC – 0.4V. EN (Pin 10): Enable Pin. When the input voltage is higher than 0.9V or up to VCC, the circuit is completely turned on. When the input voltage is less than 0.7V or down to ground, the circuit is turned off except the part of the circuit associated with standby mode. STBY (Pin 11): Standby Pin. When the input voltage is higher than 0.9V or up to V CC, the circuit of standby mode is turned on to bias the I/Q buffers to desired quiescent voltage. When the input voltage is less than 0.7V or down to ground, it is turned off. IFt+ (Pin 12): Interstage IF Positive Pin. The DC bias voltage is VCC – 0.25V. IFt– (Pin 13): Interstage IF Negative Pin. The DC bias voltage is VCC – 0.25V. RSSI (Pin 15): RSSI Output Pin. 2XLO– (Pin 18): Negative Carrier Input Pin. The input- signal’s frequency must be twice that of the desired demodulator LO frequency. The DC bias voltage is VCC – 0.4V. 2XLO+ (Pin 19): Positive Carrier Input Pin. The input- signal’s frequency must be twice that of the desired demodulator LO frequency. The DC bias voltage is V CC – 0.4V. QOUT– (Pin 23): Negative Baseband Output Pin of the Q-Channel. The DC bias voltage is VCC – 1.16V. This pin should not be shorted to ground. QOUT+ (Pin 24): Positive Baseband Output Pin of the Q-Channel. The DC bias voltage is VCC – 1.16V. This pin should not be shorted to ground. BLOCK DIAGRA W 2XLO+ 2XLO– IF+ IF– EN BIAS 5502 BD LIMITER LIMITER 12 13 1015 RSSI RSSI LO BUFFERS IFt+ IFt– IOUT+ IOUT– QOUT+ QOUT– Q-MIXER I-MIXER LPF LPF DIVIDE 2 0°/90° 19 18
grated lowpass filters (LPFs), and bias circuitry. bandwidth, the input sensitivity is improved to –86dBm. Figure 1. IF Input Matching Network at 280MHz Table 1. The Component Values of Matching Network
5502 F01
capacitor C7 is needed to reduce the RSSI voltage ripple. nitudes are well matched, and their phases are 90° apart. and the maximum charging current is more than 10mA. Table 2. The logic of different operating modes
5502 F02
Figure 2. Simplified Circuit Schematic
Figure 3. Evaluation Circuit Schematic With I/Q Output Buffers
Dimensions in inches (millimeters) unless otherwise noted. 0.337 – 0.344* (8.560 – 8.738) GN24 (SSOP) 1098 * DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 12 3 4 5 6 7 8 9 10 11 12 0.229 – 0.244 (5.817 – 6.198) 0.150 – 0.157 (3.810 – 3.988) 161718192021222324 15 1413 0.016 – 0.050 (0.406 – 1.270) 0.015 – 0.004 0° – 8° TYP0.007 – 0.0098 (0.178 – 0.249) 0.053 – 0.068 (1.351 – 1.727) 0.008 – 0.012 (0.203 – 0.305) 0.004 – 0.0098 (0.102 – 0.249) 0.0250 (0.635) BSC 0.033 (0.838) REF 24-Lead Plastic SSOP (Narrow 0.150) (LTC DWG # 05-08-1641)
Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 l FAX: (408) 434-0507 l www.linear-tech.com ª LINEAR TECHNOLOGY CORPORATION 2001 5502i LT/TP 0101 2K • PRINTED IN USA TYPICAL APPLICATIO U Example: 2.4GHz to 2.5GHz Receiver Application (RX IF = 280MHz)
5502 TA02
I OUTPUTS Q OUTPUTS A/D A/D BASEBAND PROCESSOR BUFFER BUFFER LPF LPF 90° LIMITER LIMITER STBY ENLT5502 30nH 30nH 200Ω 2.7pF 100pF 2.7pF IF SYNTHESIZER 3,5,8,9, 14,20,21 18 191.8pF 120nH 22nF3.3pF 4,16,17,22VCC 0.1µF 12 13 280MHz IF SAW BP FILTER RX FRONT END RX INPUT: 2.4GHz TO 2.5GHz MAIN SYNTHESIZER 3.3pF RSSI 2nd LO, 560MHz 1st LO, 2.12GHz TO 2.22GHz 1nF1nF