19-3469; Rev 0; 11/04 KIT ATION EVALU LE B A IL A AV Single-Chip Global Positioning System Receiver Front-End The MAX2742 complete single-chip global positioning system (GPS) RF front-end utilizes many innovative and leading-edge RF CMOS design techniques. This highperformance, state-of-the-art device consumes extremely low power and eliminates the need for costly SAW and bulky discrete IF filters. The MAX2742 incorporates a fully integrated low-noise amplifier (LNA) and mixer, IF section, digital sampler, and local oscillator synthesizer. The intended input signal for the MAX2742 is the L1 GPS signal 1.57542GHz. This device supports highaccuracy output quantization, which delivers the best performance obtainable for the GPS receiver. The power consumption of the MAX2742 is as low as 32mW at a +2.4V supply. The MAX2742 is available in a space-saving 48-pin TQFP package and is specified for the extended (-40°C to +85°C) temperature range. Features ♦ Complete Single-Chip GPS Front-End Receiver ♦ Single-Ended or Differential Outputs at 1.023MHz ♦ Low 4.5dB Typical Noise Figure ♦ No External IF SAW or Discrete Filters Required ♦ Very Low 32mW Power Consumption at +2.4V ♦ Wide +2.4V to +3.6V Operational Supply Voltage Range ♦ Extended -40°C to +85°C Temperature Range Applications Ordering Information In-Vehicle Navigation Systems (IVNS) Location-Based Services (PDAs and Accessories) PART TEMP RANGE PIN-PACKAGE MAX2742ECM -40°C to +85°C 48 TQFP-EP* *EP = Exposed paddle. Recreational Handheld/Walkie Talkies Geographical Information Systems (GISs) Block Diagram/ Pin Configuration Telematics (Vehicle, Asset Tracking, and Inventory Management) Consumer Electronics RBIAS VDD GND VDD CPOUT GND VTUNE I.C. VDD GND SHDN Digital Cameras/Camcorders XTALIN1 Emergency Response Systems XTALIN2 Emergency Roadside Assistance 48 47 46 45 44 43 42 41 40 39 38 37 36 I.C. 1 CBIAS 2 VDD 3 VDD 4 GND 5 BIAS CONTROL BLOCK CP 35 I.C. 34 I.C. TCXO BUFFER PFD 33 I.C. DIV 32 VDD MAX2742 31 DIN GND 6 RFIN 7 GND 8 29 CLKOUT2 GND 9 28 DOUT LNA 30 GND IFSEL 10 VGA 27 I.C. COMP 26 CLKOUT1 AGC I.C. 11 25 VDD 17 18 19 20 21 CLKENB1 VDD AGCFLT OUT- OUT+ I.C. 22 23 24 GND 16 I.C. 15 VDD 14 DCLK GND 13 CLKENB2 VDD 12 ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX2742 General Description MAX2742 Single-Chip Global Positioning System Receiver Front-End ABSOLUTE MAXIMUM RATINGS VDD to GND ...........................................................-0.3V to +3.7V All Other Pins to GND.................................-0.3V to (VDD + 0.3V) RF LNA Input Power .......................................................+10dBm Continuous Power Dissipation (TA = +70°C) 48-Pin TQFP-EP (derate 12.5mW/°C above +70°C) ....100mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Soldering Temperature (10s) ...........................................+300°C CAUTION! ESD SENSITIVE DEVICE Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. DC ELECTRICAL CHARACTERISTICS (MAX2742 EV kit, VDD = +2.4V to +3.6V, SHDN = VDD, TA = -40°C to +85°C. Typical values are at VDD = +3V and TA = +25°C, unless otherwise noted.) PARAMETER Supply Voltage Supply Current CONDITIONS MIN 2.4 VDD = +3.0V, TA = +25°C (Note 1) Shutdown mode TYP MAX 3.6 UNITS V 14 20 mA 10 Logic-Input High Voltage µA VDD - 0.5 V Logic-Input Low Voltage Logic-Input Bias Current -40 0.5 V +40 µA AC ELECTRICAL CHARACTERISTICS (MAX2742 EV kit, VDD = +2.4V to +3.6V, SHDN = VDD, TA = -40°C to +85°C. Typical values are at VDD = +3V and TA = +25°C, unless otherwise noted.) PARAMETER CONDITIONS MIN TYP MAX UNITS 102 117 dB GENERAL PERFORMANCE Maximum Conversion Gain (Notes 2, 3) Input Frequency Noise Figure 1575.42 MHz Measured at quantizer input 4.5 dB -15 dB f1 = 1.5MHz and f2 = 2.0MHz above carrier frequency -32 dBm 1.023 MHz Return Loss (S11) LNA/Mixer Input IP3 Output IF Frequency OUTPUT STAGE Output Rise/Fall Time Output-Voltage-Level Low Output-Voltage-Level High 2 Differential (VOUT+, VOUT-), CL < 20pF 25 Single ended (DOUT), CL < 20pF 5 Differential Single ended Differential Single ended VDD - 0.9 0 VDD _______________________________________________________________________________________ ns V V Single-Chip Global Positioning System Receiver Front-End (MAX2742 EV kit, VDD = +2.4V to +3.6V, SHDN = VDD, TA = -40°C to +85°C. Typical values are at VDD = +3V and TA = +25°C, unless otherwise noted.) PARAMETER CONDITIONS MIN TYP MAX UNITS SYNTHESIZER TCXO Input Frequency Fundamental frequency crystal Charge-Pump Current Phase Noise 18.414 MHz 0.4 mA fOFFSET = 10kHz offset, BWLOOP = 70kHz -71 fOFFSET = 1MHz offset, BWLOOP = 70kHz -106 dBc/Hz Comparison Frequency Spur BWLOOP = 70kHz VCO Turning Range (Notes 2, 3) 148 210 -66 277 MHz dBc VCO Tuning Gain (Notes 2, 3) 139 200 305 MHz/V IF STAGE IF Stage Gain VGA set at maximum gain 77 dB 50 dB Low-frequency corner 0.1 High-frequency corner 3.2 Dynamic Range IF Stage Gain Bandpass Filter 1dB Corner Frequency MHz Bandpass Filter 60dB High-Side Rejection 5.0 MHz Image Rejection 18 dB In-Band Ripple 1 dB AGC Loop Lock Time 1 ms Note 1: At TA = +25°C, min/max limits are guaranteed by production test. Note 2: At TA = -40°C, min/max limits are guaranteed by design and characterization. Note 3: At TA = +25°C and +85°C, min/max limits are guaranteed by production test. _______________________________________________________________________________________ 3 MAX2742 AC ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (MAX2742 EV kit, VDD = +3V, and TA = +25°C, unless otherwise noted.) LNA/MIXER GAIN vs. TEMPERATURE SUPPLY CURRENT vs. TEMPERATURE 14 VCC = +2.7V 13 VCC = +2.4V VCC = +2.4V 28 27 26 25 24 23 VCC = +3.0V VCC = +2.7V 22 11 MAX2742 toc02 VCC = +3.0V 29 LNA-MIXER GAIN (dB) SUPPLY CURRENT (mA) 15 12 30 MAX2742 toc01 16 21 20 10 -40 -20 0 20 40 60 -40 80 -20 0 MAXIMUM IF STAGE GAIN vs. TEMPERATURE 40 60 80 TOTAL CONVERSION GAIN vs. TEMPERATURE 104 SYSTEM GAIN (dB) 79 VCC = +2.7V 78 77 MAX2742 toc04 105 MAX2742 toc03 80 VCC = +3.0V 20 TEMPERATURE (°C) TEMPERATURE (°C) VGA GAIN (dB) MAX2742 Single-Chip Global Positioning System Receiver Front-End VCC = +3.0V 103 102 VCC = +2.7V 76 101 VCC = +2.4V VCC = +2.4V 75 100 -40 -20 0 20 40 TEMPERATURE (°C) 4 60 80 -40 -20 0 20 40 TEMPERATURE (°C) _______________________________________________________________________________________ 60 80 Single-Chip Global Positioning System Receiver Front-End PIN NAME FUNCTION 1 RBIAS External Bias Resistor. Connect a 100kΩ ±1% resistor in parallel with a 0.1µF capacitor in series with a 71kΩ resistor to GND. External Bias Capacitor. Connect a 0.1µF capacitor to GND. 2 CBIAS 3, 4, 12, 17, 23, 25, 32, 39, 44, 46 VDD Supply Voltage. Bypass to GND with a capacitor as close to the pin as possible. 5, 6, 8, 9, 13, 24, 30, 38, 42, 45 GND Ground. Connect to PC board ground plane. 7 RFIN LNA Input. Requires external matching network. 10 IFSEL IF Output Select. Selects output type. Drive high for single-ended output, drive low for differential output. 11, 21, 22, 27, 33–36, 40 I.C. Internally Connected. Leave unconnected. 14 DCLK 15 CLKENB2 Digital Control Clock 16 CLKENB1 18 AGCFLT 19, 20 OUT-, OUT+ 26 CLKOUT1 28 DOUT 29 CLKOUT2 31 DIN 37 SHDN Shutdown. Drive SHDN high to disable all device functions. Drive SHDN low for normal operation. 41 VTUNE VCO Tuning Input 43 CPOUT Charge-Pump Output. Connect directly to loop filter. 47, 48 XTALIN1, XTALIN2 EP GND Clock Output Enable 2. Drive high to enable limited-swing clock output. Clock Output Enable 1. Drive high to enable full-swing clock output. AGC External Filter Differential Comparator Outputs Full-Swing Clock Output Digital Output Limited-Swing Clock Output Digital-Control Data Input Connect XTALIN1 and XTALIN2 together and to the TCXO output through a coupling capacitor. Exposed Paddle. Connect to PC board ground plane for optimal performance. _______________________________________________________________________________________ 5 MAX2742 Pin Description MAX2742 Single-Chip Global Positioning System Receiver Front-End Detailed Description LNA/Mixer The RF input from the GPS antenna is fed through an LNA with a 24dB gain. The amplified signal is then fed to a mixer that downconverts the signal (1575.42MHz) to a quadrature differential IF of 1.023MHz. IF Stage The quadrature IF signals pass through the IF filter, which rejects the out-of-band spurs by more than 60dB and the image noise by 18dB (typ). After the image reject filter, the signal is converted from quadrature to differential. The filtered IF signal is then amplified by the AGC block, which sets the VGA output signal level to a predetermined value through the application using 50dB of dynamic range. The internal offset-cancellation mechanism generates a highpass characteristic for the IF section with a 1dB corner frequency of about 100kHz. IF Output Selection The sampled outputs of the GPS signal are available in a single-ended or differential format. The IFSEL pin controls the output format. VCO, TCXO buffer, main frequency divider, phase-frequency detector, and charge pump. It uses an off-chip PLL loop filter and TCXO. Connect the output of the TCXO to XTALIN1 and XTALIN2 through a coupling capacitor. The main division ratio for the synthesizer is 684. With this division ratio, a low-side injection LO can be synthesized with an 18.414MHz TXCO. Applications Information Layout Issues A properly designed PC board is an essential part of any RF/microwave circuit. On all high-frequency inputs and outputs, use controlled impedance lines and keep them as short as possible to minimize losses and radiation. Keeping the traces short also reduces parasitic inductance. To further reduce the parasitic inductance, use wider traces and a solid ground or power plane below the signal traces. Also, place decoupling capacitors as close to the supply pins as possible. For proper power dissipation and operation, connect the metal exposed paddle solidly to the ground plane of the PC board. Synthesizer An on-chip VCO provides quadrature differential LO signals to the downconverting mixer and controls the frequency. An on-board TCXO generates the reference frequency. The integrated synthesizer includes the 6 _______________________________________________________________________________________ Single-Chip Global Positioning System Receiver Front-End 48 GND RFIN GND GND IFSEL 41 39 SHDN GND VDD I.C. 40 38 37 36 I.C. 1 BIAS 2 3 CONTROL BLOCK CP 35 I.C. 34 I.C. TCXO BUFFER PFD 4 33 I.C. DIV 5 32 MAX2742 31 6 LNA 7 30 8 29 9 28 10 VGA I.C. 11 26 25 12 18 19 OUT- 17 AGCFLT 16 VDD 15 CLKENB1 14 CLKENB2 GND 13 20 VDD DIN GND CLKOUT2 DOUT 27 I.C. COMP AGC DCLK VDD VTUNE CPOUT VDD GND GND 42 21 22 23 CLKOUT1 VDD 24 GND GND 43 VDD VDD 44 I.C. VDD 45 I.C. CBIAS 46 OUT+ RBIAS 47 VDD XTALIN1 XTALIN2 TCXO Chip Information PROCESS: CMOS TRANSISTOR COUNT: 18443 _______________________________________________________________________________________ 7 MAX2742 Typical Application Circuit Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) 48L,TQFP.EPS MAX2742 Single-Chip Global Positioning System Receiver Front-End PACKAGE OUTLINE, 32/48L TQFP, 7x7x1.0mm EP OPTION 21-0065 F 1 2 PACKAGE OUTLINE, 32/48L TQFP, 7x7x1.0mm EP OPTION 21-0065 F 2 2 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.