19-1234; Rev 5; 8/03 KIT ATION EVALU E L B A AVAIL 900MHz Image-Reject Transceivers Features ♦ Receive/Transmit Mixers with 35dB Image Rejection ________________________Applications Cordless Phones Spread-Spectrum Communications Wireless Telemetry ♦ Adjustable-Gain LNA ♦ Up to +2dBm Combined Receiver Input IP3 ♦ 4dB Combined Receiver Noise Figure ♦ >35dB of Transmit Power Control Range ♦ PA Predriver Provides up to +2dBm ♦ Low Current Consumption: 23mA Receive 26mA Transmit 9.5mA Oscillator ♦ 0.5µA Shutdown Mode ♦ Operates from Single +2.7V to +4.8V Supply _______________Ordering Information PART TEMP RANGE PIN-PACKAGE MAX2420EAI -40°C to +85°C 28 SSOP MAX2421EAI MAX2422EAI MAX2460EAI MAX2463EAI -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C 28 SSOP 28 SSOP 28 SSOP 28 SSOP Functional Diagram appears on last page. ___________________Pin Configuration TOP VIEW VCC 1 28 GND CAP1 2 27 GND RXOUT 3 26 GND TXGAIN 4 25 TANK RXIN 5 Two-Way Paging VCC 6 Wireless Networks GND 7 ______________________Selector Guide GND 8 MAX2420 MAX2421 MAX2422 MAX2460 MAX2463 24 TANK 23 VCC 22 VCC 21 PREOUT 20 PREGND TXOUT 9 PART IF FREQ (MHz) INJECTION TYPE LO FREQ (MHz) LNAGAIN 10 19 MOD MAX2420 10.7 High side fRF + 10.7 VCC 11 18 DIV1 TXIN 12 17 VCOON MAX2421 46 High side fRF + 46 MAX2422 70 High side fRF + 70 N.C. 13 16 RXON CAP2 14 15 TXON MAX2460 10.7 Low side fRF - 10.7 MAX2463 110 Low side fRF - 110 SSOP ________________________________________________________________ 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 MAX2420/MAX2421/MAX2422/MAX2460/MAX2463 General Description The MAX2420/MAX2421/MAX2422/MAX2460/MAX2463 are highly integrated front-end ICs that provide the lowest cost solution for cordless phones and ISM-band radios operating in the 900MHz band. All devices incorporate transmit and receive image-reject mixers to reduce filter cost. They operate with a +2.7V to +4.8V power supply, allowing direct connection to a three-cell battery stack. The receive path incorporates an adjustable-gain LNA and an image-reject downconverter with 35dB image suppression. These features yield excellent combined downconverter noise figure (4dB) and high linearity with an input third-order intercept point (IP3) of up to +2dBm. The transmitter consists of a variable-gain IF amplifier with more than 35dB control range, an image-reject upconverter with 35dB image rejection, and a poweramplifier (PA) predriver that produces up to +2dBm (in some applications serving as the final power stage). All devices include an on-chip local oscillator (LO), requiring only an external varactor-tuned LC tank for operation. The integrated divide-by-64/65 dual-modulus prescaler can also be set to a direct mode, in which it acts as an LO buffer amplifier. Four separate powerdown inputs can be used for system power management, including a 0.5µA shutdown mode. These parts are compatible with commonly used modulation schemes such as FSK, BPSK, and QPSK, as well as frequency hopping and direct sequence spread-spectrum systems. All devices come in a 28-pin SSOP package. For applications using direct VCO or BPSK transmit modulation, as well as receive image rejection, consult the MAX2424/MAX2426 data sheet. For receive-only devices, refer to the MAX2440/MAX2441/MAX2442 data sheet. MAX2420/MAX2421/MAX2422/MAX2460/MAX2463 900MHz Image-Reject Transceivers ABSOLUTE MAXIMUM RATINGS VCC to GND ...........................................................-0.3V to +5.5V TXIN Input Power (330Ω system) ......................................-8dBm Voltage on TXOUT......................................-0.3V to (VCC + 1.0V) Voltage on TXGAIN, LNAGAIN, TXON, RXON, VCOON, DIV1, MOD ....................-0.3V to (VCC + 0.3V) RXIN Input Power..............................................................10dBm TANK, TANK Input Power ...................................................2dBm Continuous Power Dissipation (TA = +70°C) SSOP (derate 9.50mW/°C above +70°C) ......................762mW Operating Temperature Range MAX242_EAI/MAX246_EAI ................................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +165°C Lead Temperature (soldering, 10s) .................................+300°C 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. CAUTION! ESD SENSITIVE DEVICE DC ELECTRICAL CHARACTERISTICS (VCC = +2.7V to +4.8V, no RF signals applied, LNAGAIN = TXGAIN = open, VCOON = 2.4V, RXON = TXON = MOD = DIV1 = 0.45V, PREGND = GND, TA = TMIN to TMAX. Typical values are at TA = +25°C, VCC = +3.3V, unless otherwise noted.) (Note 1) CONDITIONS PARAMETER Supply-Voltage Range Oscillator Supply Current MIN TYP 2.7 PREGND = floating Prescaler Supply Current (divide-by-64/65 mode) (Note 2) MAX UNITS 4.8 V 9.5 14 mA 4.2 6 mA Prescaler Supply Current (buffer mode) (Note 3) DIV1 = 2.4V 5.4 8.5 mA Receive Supply Current (Note 4) RXON = 2.4V, PREGND = floating 23 36 mA Transmitter Supply Current (Note 5) RXON = 0.45V, TXON = 2.4V, PREGND = floating 26 42 mA TA = +25°C Shutdown Supply Current VCOON = RXON = TXON = MOD = DIV1 = GND Digital Input Voltage High RXON, TXON, DIV1, VCOON, MOD Digital Input Voltage Low RXON, TXON, DIV1, VCOON, MOD Digital Input Current Voltage on any one digital input = VCC or GND 0.5 TA = TMIN to TMAX 10 2.4 µA µA V ±1 0.45 V ±10 µA ≥25°C guaranteed by production test, <25°C guaranteed through correlation to worst-case temperature testing. Calculated by measuring the combined oscillator and prescaler supply current and subtracting the oscillator supply current. Calculated by measuring the combined oscillator and LO buffer supply current and subtracting the oscillator supply current. Calculated by measuring the combined receive and oscillator supply current and subtracting the oscillator supply current. With LNAGAIN = GND, the supply current drops by 4.5mA. Note 5: Calculated by measuring the combined transmit and oscillator supply current and subtracting the oscillator supply current. Note 1: Note 2: Note 3: Note 4: 2 _______________________________________________________________________________________ 900MHz Image-Reject Transceivers (MAX242X/246X EV kit, V CC = +3.3V; f LO = 925.7MHz (MAX2420), f LO = 961MHz (MAX2421), f LO = 985MHz (MAX2422), fLO = 904.3MHz (MAX2460); fLO = 805MHz (MAX2463); fRXIN = 915MHz; PRXIN = -35dBm; PTXIN = -15dBm (330Ω); LNAGAIN = 2V; TXGAIN = VCC; VCOON = 2.4V; RXON = TXON = MOD = DIV1 = PREGND = GND; TA = +25°C; unless otherwise noted.) PARAMETER CONDITIONS MIN TYP MAX UNITS 1000 MHz RECEIVER (RXON = 2.4V) Input Frequency Range (Notes 6, 7) IF Frequency Range (Notes 6, 7) 800 MAX2420/MAX2460 8.5 10.7 12.5 MAX2421 36 46 55 MAX2422 55 70 85 MAX2463 86 110 132 Image Frequency Rejection 26 35 MAX2420/MAX2421/MAX2460 20 22 24.5 MAX2422 19 21 23.5 MAX2463 18 20 22.5 LNAGAIN = VCC, MAX2420/MAX2421/MAX2460 TA = TMIN to TMAX MAX2422 (Note 6) MAX2463 19.5 25 18 24 LNAGAIN = VCC, TA = +25°C Conversion Power Gain (Note 8) 12 LNAGAIN = GND -16 DIV1 = VCC LNAGAIN = 1V Input Third-Order Intercept (Notes 6, 9) LNAGAIN = VCC LNAGAIN = VCC 4 LNAGAIN = 1V 12 -19 dB dB 23 LNAGAIN = 1V Noise Figure (Notes 6, 8) Input 1dB Compression 17 MHz 5 -17 LNAGAIN = 1V -8 LNAGAIN = VCC -26 LNAGAIN = 1V -18 dB dBm dBm LO to RXIN Leakage Receiver on or off -60 dBm Receiver Turn-On Time (Note 10) 500 ns TRANSMITTER (TXON = 2.4V) Output Frequency Range (Notes 6, 7) IF Frequency Range 800 MAX2420/MAX2460 8.5 10.7 12.5 MAX2421 36 46 55 MAX2422 55 70 85 MAX2463 86 110 132 26 35 MAX2420/2460 11 13.5 MAX2421 10 12.5 15 MAX2422 9 12 14.5 8 11 Image Frequency Rejection TA = +25°C Conversion Gain 1000 MAX2463 MAX2420/2460 MHz MHz dB 16 13.5 10.5 16.5 TA = TMIN to TMAX MAX2421 (Note 6) MAX2422 10 15.5 9 15 MAX2463 8 14 dB _______________________________________________________________________________________ 3 MAX2420/MAX2421/MAX2422/MAX2460/MAX2463 AC ELECTRICAL CHARACTERISTICS MAX2420/MAX2421/MAX2422/MAX2460/MAX2463 900MHz Image-Reject Transceivers AC ELECTRICAL CHARACTERISTICS (continued) (MAX242X/246X EV kit, V CC = +3.3V; f LO = 925.7MHz (MAX2420), f LO = 961MHz (MAX2421), f LO = 985MHz (MAX2422), fLO = 904.3MHz (MAX2460); fLO = 805MHz (MAX2463); fRXIN = 915MHz; PRXIN = -35dBm; PTXIN = -15dBm (330Ω); LNAGAIN = 2V; TXGAIN = VCC; VCOON = 2.4V; RXON = TXON = MOD = DIV1 = PREGND = GND; TA = +25°C; unless otherwise noted.) PARAMETER CONDITIONS MIN TYP MAX UNITS Output 1dB Compression 2 dBm Output Third-Order Intercept (Note 11) 11 dBm LO to TXOUT Suppression (Note 12) 34 dBc Noise Figure 23 dB 33 dB/V Gain Control Range (Note 13) 36 dB Transmitter Turn-On Time (Note 14) 400 ns TXGAIN Control Slope (Note 13) 1V ≤ TXGAIN ≤ 2V OSCILLATOR AND PRESCALER Oscillator Frequency Range (Notes 6, 15) Oscillator Phase Noise 690 1100 MHz 10kHz offset (Note 16) 82 Standby to TX, or standby to RX 8 Oscillator Pulling RX to TX with PRXIN = -45dBm (RX mode) to PRXIN = 0dBm (TX mode) (Note 17) 70 Prescaler Output Level ZL = 100kΩ | | 10pF 500 Oscillator Buffer Output Level (Note 6) DIV1 = 2.4V, ZL = 50Ω, TA = +25°C -11 DIV1 = 2.4V, ZL = 50Ω, TA = TMIN to TMAX -12 Required Modulus Setup Time (Note 6) Divide-by-64/65 mode (Note 18) 10 ns Required Modulus Hold Time (Note 6) Divide-by-64/65 mode (Note 18) 0 ns -8 dBc/Hz kHz mVP-P dBm Note 6: Guaranteed by design and characterization. Note 7: Image rejection typically falls to 30dBc at the frequency extremes. Note 8: Refer to the Typical Operating Characteristics for plots showing receiver gain vs. LNAGAIN voltage, input IP3 vs. LNAGAIN voltage, and noise figure vs. LNAGAIN voltage. Note 9: Two tones at PRXIN = -45dBm each, f1 = 915.0MHz and f2 = 915.2MHz. Note 10: Time delay from RXON = 0.45V to RXON = 2.4V transition to the time the output envelope reaches 90% of its final value. Note 11: Two tones at PTXIN = -21dBm each (330Ω), f1 = 10.6MHz, f2 = 10.8MHz (MAX2420/MAX2460), f1 = 45.9MHz, f2 = 46.1MHz (MAX2421), f1 = 69.9MHz, f2 = 70.1MHz (MAX2422). Note 12: Refer to the Typical Operating Characteristics for statistical data. Note 13: Refer to the Typical Operating Characteristics for a plot showing transmitter gain vs. TXGAIN voltage. Note 14: Time delay from TXON = 0.45V to TXON = 2.4V transition to the time the output envelope reaches 90% of its final value. Note 15: Refers to useable operating range. Tuning range of any given tank circuit design is typically much narrower (refer to Figure 2). Note 16: Using tank components L3 = 5.0nH (Coilcraft A02T), C2 = C3 = C26 = 3.3pF, R6 = R7 = 10Ω. Note 17: This approximates a typical application in which TXOUT is followed by an external PA and a T/R switch with finite isolation. Note 18: Relative to the rising edge of PREOUT. 4 _______________________________________________________________________________________ 900MHz Image-Reject Transceivers TRANSMITTER SUPPLY CURRENT vs. TEMPERATURE 44 42 VCC = 4.8V VCC = 3.3V 32 VCC = 2.7V TXON = VCC PREGND = FLOATING INCLUDES OSCILLATOR CURRENT 28 -20 20 40 60 80 -20 0 20 40 60 80 -40 100 -20 0 20 40 60 TEMPERATURE (°C) RECEIVER GAIN vs. LNAGAIN RECEIVER INPUT IP3 vs. VLNAGAIN RECEIVER NOISE FIGURE vs. LNAGAIN LNA OFF 0 LNA ADJUSTABLE MAX PARTIALLY GAIN GAIN BIASED 5 ADJUSTABLE GAIN 0 IIP3 (dBm) 10 MAX GAIN -5 AVOID THIS REGION -10 -15 -5 -10 1.5 2.0 20 15 DIV1 = VCC RXON = VCC AVOID THIS REGION 0 0 0.5 1.0 1.5 2.0 0 0.5 1.0 1.5 LNAGAIN VOLTAGE (V) LNAGAIN VOLTAGE (V) LNAGAIN VOLTAGE (V) MAX2420 RECEIVER GAIN vs. TEMPERATURE RECEIVER NOISE FIGURE vs. TEMPERATURE AND SUPPLY VOLTAGE RECEIVER INPUT IP3 vs. TEMPERATURE LNAGAIN = VCC RXON = VCC DIV1 = VCC 5.0 VCC = 4.8V 22 VCC = 3.3V 20 -8 LNAGAIN = 1V -10 VCC = 4.8V 4.5 IIP3 (dBm) NOISE FIGURE (dB) VCC = 2.7V 24 2.0 -6 MAX2420-08 5.5 MAX2420-07 LNAGAIN = VCC RXON = VCC 100 25 RXON = VCC -20 1.0 LNA ADJUSTABLE MAX PARTIALLY GAIN GAIN BIASED 5 RXON = VCC 0.5 LNA OFF 10 -15 -20 0 35 30 AVOID THIS REGION 80 40 NOISE FIGURE (dB) LNA PARTIALLY BIASED MAX2420-05 5 MAX2420-04 LNA OFF 26 VCC = 2.7V TEMPERATURE (°C) 15 RECEIVER GAIN (dB) 0.5 0 -40 100 VCC = 4.8V TEMPERATURE (°C) 25 20 0 VCC = 3.3V 2.0 1.0 26 -40 2.5 1.5 30 24 RECEIVER GAIN (dB) VCC = 2.7V 32 RXON = VCC PREGND = FLOATING INCLUDES OSCILLATOR CURRENT 26 VCC = 3.3V 36 34 30 28 3.0 38 MAX2420-09 34 3.5 VCC = 4.8V 40 ICC (mA) ICC (mA) 36 ICC (µA) 38 VCOON = GND 4.0 MAX2420-06 40 4.5 MAX2420-02 46 MAX2420-01 42 SHUTDOWN SUPPLY CURRENT vs. TEMPERATURE MAX2420-03 RECEIVER SUPPLY CURRENT vs. TEMPERATURE VCC = 3.3V 4.0 VCC = 2.7V -12 -14 -16 LNAGAIN = 2V 3.5 -18 18 RXON = VCC 3.0 -40 -20 0 20 40 60 TEMPERATURE (°C) 80 100 -20 -40 -20 0 20 40 60 TEMPERATURE (°C) 80 100 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) _______________________________________________________________________________________ 5 MAX2420/MAX2421/MAX2422/MAX2460/MAX2463 Typical Operating Characteristics (MAX242X/246X EV kit, VCC = +3.3V; fLO = 925.7MHz (MAX2420), fLO = 961MHz (MAX2421), fLO = 985MHz (MAX2422), fLO = 904.3MHz (MAX2460); fLO = 805MHz (MAX2463); fRXIN = 915MHz; PRXIN = -35dBm; PTXIN = -15dBm (330Ω); LNAGAIN = 2V; TXGAIN = VCC; VCOON = 2.4V; RXON = TXON = MOD = DIV1 = PREGND = GND; TA = +25°C; unless otherwise noted.) Typical Operating Characteristics (continued) (MAX242X/246X EV kit, VCC = +3.3V; fLO = 925.7MHz (MAX2420), fLO = 961MHz (MAX2421), fLO = 985MHz (MAX2422), fLO = 904.3MHz (MAX2460); fLO = 805MHz (MAX2463); fRXIN = 915MHz; PRXIN = -35dBm; PTXIN = -15dBm (330Ω); LNAGAIN = 2V; TXGAIN = VCC; VCOON = 2.4V; RXON = TXON = MOD = DIV1 = PREGND = GND; TA = +25°C; unless otherwise noted.) RXON = VCC 50 IMAGE REJECTION (dB) VCC = 4.8V -5 VCC = 2.7V -6 VCC = 3.3V -7 40 MAX2420 30 20 10 MAX2422 MAX2463 MAX2421 40 30 20 0 0 -20 0 20 40 60 0 80 400 800 1200 1600 1000 IF FREQUENCY (MHz) RXIN INPUT IMPEDANCE vs. FREQUENCY TRANSMITTER GAIN vs. TXGAIN VOLTAGE MAX2420 TRANSMITTER GAIN vs. TEMPERATURE 35 IMAGINARY 30 25 -60 REAL 20 -40 15 10 10 -20 VCC = 3.3V 0 VCC = 4.8V VCC = 2.7V 16 TRANSMITTER GAIN (dB) -80 TRANSMITTER GAIN (dB) 40 18 -10 -20 -30 5 800 1000 1200 0.5 1400 VCC = 2.7V 12 VCC = 3.3V 10 8 6 TXON = VCC 2 -40 -0 VCC = 4.8V 14 4 TXON = VCC 0 MAX2420 toc16 20 -100 RXON = VCC 45 1.0 1.5 2.0 -40 2.5 3.0 3.5 4.0 4.5 5.0 -20 0 20 40 60 80 100 FREQUENCY (MHz) TXGAIN VOLTAGE (V) TEMPERATURE (°C) TXOUT OUTPUT IMPEDANCE vs. FREQUENCY MAX2420 TRANSMITTER OUTPUT SPECTRUM MAX2460 TRANSMITTER OUTPUT SPECTRUM -10 TXON = VCC FUNDAMENTAL IMAGINARY -100 -150 POWER (dBm) -20 0 -30 -40 0 LO IMAGE -50 -10 -40 -70 -80 -250 -80 -90 -90 -100 FREQUENCY (MHz) LO -60 -70 600 800 1000 1200 1400 1600 1800 2000 IMAGE -50 -200 TXON = VCC FUNDAMENTAL -30 -60 -300 TXON = VCC -20 POWER (dBm) REAL 0 MAX2420/21/22 toc18 100 10 MAX2420toc17 150 -50 100 RF FREQUENCY (MHz) MAX2420 toc14 600 10 TEMPERATURE (°C) 50 50 1 2000 MAX2420 toc15 -20 IMAGINARY IMPEDANCE (Ω) -40 REAL IMPEDANCE (Ω) 10 -10 MAX2420/21/22 toc18.1 -8 -9 6 RXON = VCC MAX2460 50 IMAGE REJECTION (dB) -4 60 MAX2420-11 RXON = VCC 1dB COMPRESSION POINT (dBm) 60 MAX2420-10 -3 RECEIVER IMAGE REJECTION vs. IF FREQUENCY RECEIVER IMAGE REJECTION vs. RF FREQUENCY MAX2420-12 MAX2420 RXOUT 1dB COMPRESSION POINT vs. TEMPERATURE REAL OR IMAGINARY IMPEDANCE (Ω) MAX2420/MAX2421/MAX2422/MAX2460/MAX2463 900MHz Image-Reject Transceivers 875 885 895 905 915 925 935 945 955 965 975 855 865 875 885 895 905 915 925 935 945 955 FREQUENCY (MHz) FREQUENCY (MHz) _______________________________________________________________________________________ 900MHz Image-Reject Transceivers -40 -50 -60 FUNDAMENTAL -20 -40 -50 -60 -60 -80 -90 -90 -90 -100 -100 -100 1210 735 835 935 14 12 10 8 6 4 655 1005 705 MAX2420 TRANSMITTER IM3 REJECTION vs. TXGAIN VOLTAGE VCC = 4.8V 2.0 VCC = 3.3V 1.5 1.0 VCC = 2.7V 0.5 -1.0 TXON = VCC f1 = 10.6MHz f2 = 10.8MHz -21dBm PER TONE 52 50 48 VCC = 3.3V 46 VCC = 4.8V 44 VCC = 2.7V 42 -40 24 26 28 30 32 34 36 38 40 42 44 46 48 50 -20 0 20 40 60 80 100 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 LO SUPPRESSION (dBc) TEMPERATURE (°C) TXGAIN VOLTAGE (V) TRANSMITTER IMAGE REJECTION vs. RF FREQUENCY TRANSMITTER IMAGE REJECTION vs. IF FREQUENCY PRESCALER OUTPUT LEVEL vs. LOAD RESISTANCE 30 25 20 15 25 20 15 5 0 0 RF FREQUENCY (MHz) 1700 2100 MAX2463 30 5 1300 1 550 500 450 400 350 300 250 200 150 LOAD IS PLOTTED RESISTANCE IN PARALLEL WITH A 10pF OSCILLOSCOPE PROBE (÷ 64/65 MODE) 100 50 TXON = VCC 0 10 100 IF FREQUENCY (MHz) 1000 5.0 MAX2420/21/22 toc24 MAX2422 35 10 900 MAX2421 MAX2460 40 10 500 MAX2420 PRESCALER OUTPUT LEVEL (mVp-p) 35 50 45 MAX2420-22 TXON = VCC IMAGE REJECTION (dB) MAX2420/21/22 toc21 45 1105 54 0 0 1055 TRANSMITTER 1dB COMPRESSION POINT vs. TEMPERATURE 2.5 -0.5 100 605 1235 FREQUENCY (MHz) TXON = VCC 2 40 1135 3.0 OUTPUT 1dB COMPRESSION (dBm) TXON = VCC 16 MAX2420/21/22 toc18.5 18 1035 FREQUENCY (MHz) IM3 REJECTION 1110 MAX2420/21/22toc19 1010 IMAGE -50 -70 910 LO -40 -80 MAX2420 TRANSMITTER LO SUPPRESSION HISTOGRAM (n = 86) COUNT -30 -80 FREQUENCY (MHz) FUNDAMENTAL -20 -70 810 TXON = VCC -10 -70 710 IMAGE REJECTION (dB) IMAGE LO -30 POWER (dBm) POWER (dBm) -30 IMAGE -10 0 MAX2420/21/22 toc18.4 LO TXON = VCC POWER (dBm) FUNDAMENTAL -20 0 MAX2463 TRANSMITTER OUTPUT SPECTRUM MAX2420/21/22 toc18.3 -10 TXON = VCC MAX2420/21/22 toc18.2 0 MAX2422 TRANSMITTER OUTPUT SPECTRUM MAX2420/21/22 toc20 MAX2421 TRANSMITTER OUTPUT SPECTRUM 1 100 1k 10k 100k LOAD RESISTANCE (Ω) _______________________________________________________________________________________ 7 MAX2420/MAX2421/MAX2422/MAX2460/MAX2463 Typical Operating Characteristics (continued) (MAX242X/246X EV kit, VCC = + 3.3V; fLO = 925.7MHz (MAX2420), fLO = 961MHz (MAX2421), fLO = 985MHz (MAX2422), fLO = 904.3MHz (MAX2460); fLO = 805MHz (MAX2463); fRXIN = 915MHz; PRXIN = -35dBm; PTXIN = -15dBm (330Ω); LNAGAIN = 2V; TXGAIN = VCC; VCOON = 2.4V; RXON = TXON = MOD = DIV1 = PREGND = GND; TA = +25°C; unless otherwise noted.) 900MHz Image-Reject Transceivers MAX2420/MAX2421/MAX2422/MAX2460/MAX2463 Pin Description 8 PIN NAME FUNCTION 1 VCC 2 CAP1 3 RXOUT Single-Ended, 330Ω IF Output. AC couple to this pin. 4 TXGAIN Transmit Gain-Control Input. Connect to VCC for highest gain and best temperature stability. When driven with a control voltage, the IF buffer gain can be adjusted over a 36dB range (see Typical Operating Characteristics). 5 RXIN Receiver RF Input, single-ended. The input match shown in Figure 1 maintains an input VSWR of better than 2:1 from 902MHz to 928MHz. 6 VCC Supply Voltage Input for Receive Low-Noise Amplifier. Bypass with a 47pF low-inductance capacitor to GND (pin 7 if possible). 7 GND Ground Connection for Receive Low-Noise Amplifier 8 GND Ground Connection for Signal-Path Blocks, except LNA 9 TXOUT Supply-Voltage Input for Master Bias Cell. Bypass with a 47pF low-inductance capacitor and 0.1µF to GND (pin 28, if possible). Receive Bias Compensation Pin. Bypass with a 47pF low-inductance capacitor and 0.01µF to GND. Do not make any other connections to this pin. PA Predriver Output. See Figure 1 for an example matching network, which provides better than 2:1 VSWR from 902MHz to 928MHz. 10 LNAGAIN Low-Noise Amplifier Gain-Control Input. Drive this pin high for maximum gain. When LNAGAIN is pulled low, the LNA is capacitively bypassed and the supply current is reduced by 4.5mA. This pin can also be driven with an analog voltage to adjust the LNA gain in intermediate states. Refer to the Receiver Gain vs. LNAGAIN Voltage graph in the Typical Operating Characteristics, as well as Table 1. 11 VCC Supply Voltage Input for Signal-Path Blocks, except LNA. Bypass with a 47pF low-inductance capacitor and 0.01µF to GND (pin 8, if possible). 12 TXIN Transmitter IF Input, 330Ω, single-ended. AC couple to this pin. 13 N.C. No Connect. Not internally connected. 14 CAP2 Transmit Bias Compensation Pin. Bypass with a 47pF low-inductance capacitor and 0.01µF to GND. Do not make any other connections to this pin. 15 TXON Driving TXON with a logic high enables the transmit IF variable-gain amplifier, upconverter mixer, and PA predriver. VCOON must also be high. 16 RXON Driving RXON with a logic high enables the LNA, receive mixer, and IF output buffer. VCOON must also be high. 17 VCOON 18 DIV1 Driving DIV1 with a logic high disables the divide-by-64/65 prescaler and connects the PREOUT pin directly to an oscillator buffer amplifier, which outputs -8dBm into a 50Ω load. Tie DIV1 low for divide-by64/65 operation. Pull this pin low when in shutdown to minimize off current. 19 MOD Modulus Control for the Divide-by-64/65 Prescaler: high = divide-by-64, low = divide-by-65. Note that the DIV1 pin must be at logic low when using the prescaler mode. 20 PREGND Ground connection for the Prescaler. Tie PREGND to ground for normal operation. Leave floating to disable the prescaler and the output buffer. Tie MOD and DIV1 to ground and leave PREOUT floating when disabling the prescaler. 21 PREOUT Prescaler/Oscillator Buffer Output. In divide-by-64/65 mode (DIV1 = low), the output level is 500mVp-p into a high-impedance load. In divide-by-1 mode (DIV1 = high), this output delivers -8dBm into a 50Ω load. AC couple to this pin. Driving VCOON with a logic high turns on the VCO, phase shifters, VCO buffers, and prescaler. The prescaler can be selectively disabled by floating the PREGND pin. _______________________________________________________________________________________ 900MHz Image-Reject Transceivers PIN NAME FUNCTION 22 VCC Supply-Voltage Input for Prescaler. Bypass with a 47pF low-inductance capacitor and 0.01µF to GND (pin 20 if possible). 23 VCC Supply-Voltage Input for VCO and Phase Shifters. Bypass with a 47pF low-inductance capacitor to GND (pin 26 if possible). 24 TANK Differential Oscillator Tank Port. See Applications Information for information on tank circuits or on using an external oscillator. 25 TANK Differential Oscillator Tank Port. See Applications Information for information on tank circuits or on using an external oscillator. 26 GND Ground Connection for VCO and Phase Shifters 27 GND Ground (substrate) 28 GND Ground Connection for Master Bias Cell VCC 0.1µF VCC VCC 28 2 GND PREGND VCC GND 8.2nH 5 RXIN VCC 12nH 47pF TRANSMIT RF OUTPUT 20 23 MAX2420 MAX2421 MAX2422 26 MAX2460 MAX2463 47pF 47pF 22nH MAX2420 MAX2421 MAX2422 MAX2460 MAX2463 RXOUT 3 6 47pF 7 TXIN 0.01µF VARACTOR: ALPHA SMV1299-004 OR EQUIVALENT VCC GND 25 4 10 47pF 4.0 4.0 2.4 4.7 20 15 15 6.8 100nH 1kΩ 47kΩ L3 C26 R6 TANK VCO ADJUST 47pF GND CAP2 PREOUT TXGAIN MOD DIV1 VCOON RXON TXON 47pF TXGAIN LNAGAIN 3.0 1.5 VCC 1000pF 0.01µF 10 15 R7 VCC 47pF 14 3.3 4.0 C2 24 8 1.8 3.6 3.3 3.3 6.8 TRANSMIT IF INPUT (330Ω) TANK 11 6.8 RECEIVE IF OUTPUT (330Ω) 12 TXOUT VCC C26 (pF) 0.01µF 47pF 18nH C2, C3 R6, R7 (Ω) (pF) L3 (nH) SEE APPLICATIONS INFORMATION SECTION L3: COILCRAFT 0805HS-060TJBC COILCRAFT 0805HS-030TJBC 27 0.01µF 9 PART 0.01µF VCC CAP1 GND RECEIVE RF INPUT 22 47pF 47pF 0.1µF VCO TANK COMPONENTS FOR 915MHz TYPICAL RF VCC 1 LNAGAIN 21 19 18 17 16 15 C3 1kΩ TO PLL MOD DIV1 VCOON RXON TXON Figure 1. Typical Operating Circuit _______________________________________________________________________________________ 9 MAX2420/MAX2421/MAX2422/MAX2460/MAX2463 Pin Description (continued) MAX2420/MAX2421/MAX2422/MAX2460/MAX2463 900MHz Image-Reject Transceivers Detailed Description The following sections describe each of the functional blocks shown in the Functional Diagram. Receiver The MAX2420/MAX2421/MAX2422/MAX2460/MAX2463’s receive path consists of a 900MHz low-noise amplifier, an image-reject mixer, and an IF buffer amplifier. The LNA’s gain and biasing are adjustable through the LNAGAIN pin. Proper operation of this pin can provide optimum performance over a wide range of signal levels. The LNA can be placed in four modes by applying a DC voltage on the LNAGAIN pin. See Table 1, as well as the relevant Typical Operating Characteristics plots. At low LNAGAIN voltages, the LNA is shut off, and the input signal capacitively couples directly into the mixer to provide maximum linearity for large-signal operation (receiver close to transmitter). As the LNAGAIN voltage is raised, the LNA begins to turn on. Between 0.5V and 1V at LNAGAIN, the LNA is partially biased and behaves like a Class C amplifier. Avoid this operating mode for applications where linearity is a concern. As the LNAGAIN voltage reaches 1V, the LNA is fully biased into Class A mode, and the gain is monotonically adjustable at LNAGAIN voltages above 1V. See the Receiver Gain, Receiver IP3, and Receiver Noise Figure vs. LNAGAIN plots in the Typical Operating Characteristics for more information. The downconverter is implemented using an imagereject mixer consisting of an input buffer with two outputs, each of which is fed to a double-balanced mixer. The local-oscillator (LO) port of each mixer is driven from a quadrature LO. The LO is generated from an onchip oscillator and an external tank circuit. Its signal is buffered and split into phase shifters, which provide 90° of phase shift across their outputs. This pair of LO signals is fed to the mixers. The mixers’ outputs are then passed through a second pair of phase shifters, which provide a 90° phase shift across their outputs. The Table 1. LNA Modes LNAGAIN VOLTAGE (V) 0 < V ≤ 0.5 MODE LNA capacitively bypassed, minimum gain, maximum IP3 0.5 < V < 1.0 LNA partially biased. Avoid this mode— the LNA operates in a Class C manner 1.0 < V ≤ 1.5 LNA gain is monotonically adjustable 1.5 < V ≤ VCC LNA at maximum gain (remains monotonic) 10 resulting mixer outputs are then summed together. The final phase relationship is such that the desired signal is reinforced and the image signal is canceled. The downconverter mixer output appears on the RXOUT pin, a single-ended 330Ω output. Transmitter The transmitter operates similarly to the receiver, but with the phase shifters at the mixer inputs. The transmitter consists of an input buffer amplifier with more than 36dB of gain-adjustment range via the TXGAIN pin. This buffer’s output is split internally into an in-phase (I) and a quadrature-phase (Q) path. IF phase-shifting networks give the Q-channel path a 90° phase shift with respect to the I channel. The I and Q signals are input to a pair of double-balanced mixers, driven with quadrature LO. The mixer outputs are then summed, canceling the image component. The image-rejected output signal is fed to the PA predriver, which outputs typically -3dBm on the TXOUT pin. Since the transmit and receive sections share an LO and an IF frequency, interference results if both sections are active at the same time. Phase Shifters MAX2420/MAX2421/MAX2422/MAX2460/MAX2463 devices use passive networks to provide quadrature phase shifting for the receive IF, transmit IF, and LO signals. Because these networks are frequency selective, proper part selection is important. Image rejection degrades as the IF and RF move away from the designed optimum frequencies. The MAX2420/ MAX2421/MAX2422’s phase shifters are arranged such that the LO frequency is higher than the RF carrier frequency (high-side injection), while the MAX2460/ MAX2463’s phase shifters are arranged such that the LO frequency is lower than the RF carrier frequency (low-side injection). Refer to the Selector Guide. Local Oscillator (LO) The on-chip LO is formed by an emitter-coupled differential pair. An external LC resonant tank sets the oscillation frequency. A varactor diode is typically used to create a voltage-controlled oscillator (VCO). See the Applications Information section for an example VCO tank circuit. The LO may be overdriven in applications where an external signal is available. The external LO signal should be about 0dBm from 50Ω, and should be AC coupled into either the TANK or TANK pin. Both TANK and TANK require pull-up resistors to VCC. See the Applications Information section for details. ______________________________________________________________________________________ 900MHz Image-Reject Transceivers Prescaler The on-chip prescaler can be used in two different modes: as a dual-modulus divide-by-64/65, or as oscillator buffer amplifier. The DIV1 pin controls this function. When DIV1 is low, the prescaler is in dual-modulus divide-by-64/65 mode; when it is high, the prescaler is disabled and the oscillator buffer amplifier is enabled. The buffer typically outputs -8dBm into a 50Ω load. To minimize shutdown supply current, pull the DIV1 pin low when in shutdown mode. In divide-by-64/65 mode, the division ratio is controlled by the MOD pin. When MOD is high, the prescaler is in divide-by-64 mode; when it is low, it divides the LO frequency by 65. The DIV1 pin must be at a logic low in this mode. To disable the prescaler entirely, leave PREGND and PREOUT floating. Also tie the MOD and DIV1 pins to GND. Disabling the prescaler does not affect operation of the VCO stage. Power Management MAX2420/MAX2421/MAX2422/MAX2460/MAX2463 supports four different power-management features to conserve battery life. The VCO section has its own control pin (VCOON), which also serves as a master bias pin. When VCOON is high, the LO, quadrature LO phase shifters, and prescaler or LO buffer are all enabled. The VCO can be powered up prior to either transmitting or receiving, to allow it to stabilize. For transmit-to-receive switching, the receiver and transmitter sections have their own enable control inputs, RXON and TXON. With VCOON high, bringing RXON high enables the receive path, which consists of the LNA, image-reject mixers, and IF output buffer. When this pin is low, the receive path is inactive. The TXON input enables the IF adjustable-gain amplifier, upconverter mixer, and PA predriver. VCOON must be high for the transmitter to operate. When TXON is low, the transmitter is off. To disable all chip functions and reduce the supply current to typically less than 0.5µA, pull VCOON, DIV1, MOD, RXON, and TXON low. Applications Information Oscillator Tank The on-chip oscillator requires a parallel-resonant tank circuit connected across TANK and TANK. Figure 2 shows an example of an oscillator tank circuit. Inductor L4 provides DC bias to the tank ports. Inductor L3, capacitor C26, and the series combination of capacitors C2, C3, and both halves of the varactor diode capacitance set the resonant frequency as follows: 1 fr = 2π L3 CEFF ( )( CEFF = ) 1 1 1 2 C2 + C3 + C D1 + C26 where CD1 is the capacitance of one varactor diode. Choose tank components according to your application needs, such as phase-noise requirements, tuning range, and VCO gain. High-Q inductors such as aircore micro springs yield low phase noise. Use a low tolerance inductor (L3) for predictable oscillation frequency. Resistors R6 and R7 can be chosen from 0 to 20Ω to reduce the Q of parasitic resonance due to series package inductance (LT). Keep R6 and R7 as small as possible to minimize phase noise, yet large enough to ensure oscillator start up in fundamental mode. Oscillator start-up is most critical with high tuning bandwidth (low tank Q) and high temperature. Capacitors C2 and C3 couple in the varactor. Light MAX2420 MAX2421 MAX2422 MAX2460 MAX2463 VCC L4 100nH C2 R7 1/2 D1 R8 47kΩ LT L3 C26 C3 LT R5 1kΩ R6 1/2 D1 VCO_CTRL C1 47pF R4 1kΩ D1 = ALPHA SMV1299-004 SEE FIGURE 1 FOR R6, R7, C2, C3, C26, AND L3 COMPONENT VALUES. Figure 2. Oscillator Tank Schematic, Using the On-Chip VCO ______________________________________________________________________________________ 11 MAX2420/MAX2421/MAX2422/MAX2460/MAX2463 The local oscillator is resistant to LO pulling caused by changes in load impedance that occur as the part is switched from standby mode, with just the oscillator running to either transmit or receive mode. The amount of LO pulling is affected if there is power at the RXIN port in transmit mode. The most common cause of this is imperfect isolation in an external transmit/receive (T/R) switch. The AC Electrical Characteristics table contains specifications for this case as well. MAX2420/MAX2421/MAX2422/MAX2460/MAX2463 900MHz Image-Reject Transceivers coupling of the varactor is a way to reduce the effects of high-varactor tolerance and increase loaded Q. For a wider tuning range use larger values for C2 and C3 or a varactor with a large capacitance ratio. Capacitor C26 is used to trim the tank oscillator frequency. Larger values for C26 helps negate the effect of stray PCB capacitance and parasitic inductor capacitance (L3). Choose a low-tolerance capacitor for C26. For applications that require a wide tuning range and low phase noise, a series coupled resonant tank may be required as shown in Figure 4. This tank uses the package inductance in series with inductors L1, L2, and capacitance of varactor D1 to set the net equivalent inductance which resonates in parallel with the internal oscillator capacitance. Inductors L1 and L2 can be implemented as microstrip inductors, saving component cost. Bias is provided to the tank port through chokes L3 and L5. R1 and R3 should be chosen large enough to de-Q the parasitic resonance due to L3 and L5, but small enough to minimize the voltage drop across them due to bias current. Values for R1 and R3 should be kept between 0 and 50Ω. Proper high-frequency bypassing (C1) should be used for the bias voltage to eliminate power supply noise from entering the tank. Oscillator-Tank PC Board Layout The parasitic PC board capacitance, as well as PCB trace inductance and package inductance, can affect oscillation frequency, so be careful in laying out the PC board for the oscillator tank. Keep the tank layout as symmetrical, tightly packed, and close to the device as possible to minimize LO feedthrough. When using a PC board with a ground plane, a cut-out in the ground plane (and any other planes) below the oscillator tank reduces parasitic capacitance. Using an External Oscillator VCC MAX2420 MAX2421 MAX2422 TANK MAX2460 MAX2463 CBLOCK 0.01µF 50Ω EXT LO VCC 50Ω EXTERNAL LO LEVEL IS 0dBm FROM A 50Ω SOURCE. TANK Figure 3. Using an External Local Oscillator MAX2420 MAX2421 MAX2422 MAX2460 MAX2463 LT TANK If an external 50Ω LO signal source is available, it can be used as an input to the TANK or TANK pin in place of the on-chip oscillator (Figure 3). The oscillator signal is AC coupled into the TANK pin and has a level of about 0dBm from a 50Ω source. For proper biasing of the oscillator input stage, the TANK and TANK pins must be pulled up to the VCC supply via 50Ω resistors. If the application requires overdriving the internal oscillator, the pull-up resistors can be increased in order to save power. If a differential LO source such as the MAX2620 is available, AC couple the inverting output into TANK. L3 L1 R1 L4 R2 Ci C2 L2 LT L5 R3 TANK Figure 4. Series Coupled Resonant Tank for Wide Tuning Range and Low Phase Noise 12 VCC VTUNE ______________________________________________________________________________________ C1 900MHz Image-Reject Transceivers LNAGAIN 90° Σ RXIN RXOUT 0° DIV1 MOD CAP1 RXON TXON 0° CAP2 TXOUT PREOUT ÷1/64/65 PREGND TANK PHASE SHIFTER MAX2420 MAX2421 MAX2422 MAX2460* MAX2463* *CRISS-CROSSED PHASE-SHIFTER CONNECTIONS 90° BIAS 0° TANK VCOON 90° 90° Σ TXIN 0° TXGAIN ______________________________________________________________________________________ 13 MAX2420/MAX2421/MAX2422/MAX2460/MAX2463 Functional Diagram 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.) 2 SSOP.EPS MAX2420/MAX2421/MAX2422/MAX2460/MAX2463 900MHz Image-Reject Transceivers 1 INCHES E H MILLIMETERS DIM MIN MAX MIN MAX A 0.068 0.078 1.73 1.99 A1 0.002 0.008 0.05 0.21 B 0.010 0.015 0.25 0.38 C 0.20 0.09 0.004 0.008 SEE VARIATIONS D E e 0.205 0.212 0.0256 BSC 5.20 INCHES D D D D D 5.38 MILLIMETERS MIN MAX MIN MAX 0.239 0.239 0.278 0.249 0.249 0.289 6.07 6.07 7.07 6.33 6.33 7.33 0.317 0.397 0.328 0.407 8.07 10.07 8.33 10.33 N 14L 16L 20L 24L 28L 0.65 BSC H 0.301 0.311 7.65 7.90 L 0.025 0∞ 0.037 8∞ 0.63 0∞ 0.95 8∞ N A C B e L A1 D NOTES: 1. D&E DO NOT INCLUDE MOLD FLASH. 2. MOLD FLASH OR PROTRUSIONS NOT TO EXCEED .15 MM (.006"). 3. CONTROLLING DIMENSION: MILLIMETERS. 4. MEETS JEDEC MO150. 5. LEADS TO BE COPLANAR WITHIN 0.10 MM. PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE, SSOP, 5.3 MM APPROVAL DOCUMENT CONTROL NO. 21-0056 REV. C 1 1 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. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 14 © 2003 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.