19-4786; Rev 1; 11/98 L MANUA ION KIT HEET T A U L EVA TA S WS DA FOLLO 400MHz to 2.5GHz, Low-Noise, SiGe Downconverter Mixers The MAX2680/MAX2681/MAX2682 miniature, low-cost, low-noise downconverter mixers are designed for lowvoltage operation and are ideal for use in portable communications equipment. Signals at the RF input port are mixed with signals at the local oscillator (LO) port using a double-balanced mixer. These downconverter mixers operate with RF input frequencies between 400MHz and 2500MHz, and downconvert to IF output frequencies between 10MHz and 500MHz. The MAX2680/MAX2681/MAX2682 operate from a single +2.7V to +5.5V supply, allowing them to be powered directly from a 3-cell NiCd or a 1-cell Lithium battery. These devices offer a wide range of supply currents and input intercept (IIP3) levels to optimize system performance. Additionally, each device features a low-power shutdown mode in which it typically draws less than 0.1µA of supply current. Consult the Selector Guide for various combinations of IIP3 and supply current. Features ♦ 400MHz to 2.5GHz Operation ♦ +2.7V to +5.5V Single-Supply Operation ♦ Low Noise Figure: 6.3dB at 900MHz (MAX2680) ♦ High Input Third-Order Intercept Point (IIP3 at 2450MHz) -6.9dBm at 5.0mA (MAX2680) +1.0dBm at 8.7mA (MAX2681) +3.2dBm at 15.0mA (MAX2682) ♦ <0.1µA Low-Power Shutdown Mode ♦ Ultra-Small Surface-Mount Packaging Ordering Information The MAX2680/MAX2681/MAX2682 are manufactured on a high-frequency, low-noise, advanced silicon-germanium process and are offered in the space-saving 6-pin SOT23 package. PART TEMP. RANGE PINSOT PACKAGE TOP MARK MAX2680EUT-T -40°C to +85°C 6 SOT23-6 AAAR MAX2681EUT-T MAX2682EUT-T -40°C to +85°C -40°C to +85°C 6 SOT23-6 6 SOT23-6 AAAS AAAT Pin Configuration Applications 400MHz/900MHz/2.4GHz ISM-Band Radios TOP VIEW Personal Communications Systems (PCS) Cellular and Cordless Phones LO 1 6 SHDN 5 VCC 4 IFOUT Wireless Local Loop IEEE-802.11 and Wireless Data GND 2 MAX2680 MAX2681 MAX2682 RFIN 3 SOT23-6 Typical Operating Circuit appears at end of data sheet. Selector Guide FREQUENCY PART ICC (mA) 900MHz 1950MHz 2450MHz IIP3 (dBm) NF (dB) GAIN (dB) IIP3 (dBm) NF (dB) GAIN (dB) IIP3 (dBm) NF (dB) GAIN (dB) 5.0 -12.9 6.3 11.6 -8.2 8.3 7.6 -6.9 11.7 7.0 MAX2681 8.7 -6.1 7.0 14.2 +0.5 11.1 8.4 +1.0 12.7 7.7 MAX2682 15.0 -1.8 6.5 14.7 +4.4 10.2 10.4 +3.2 13.4 7.9 MAX2680 ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. MAX2680/MAX2681/MAX2682 General Description MAX2680/MAX2681/MAX2682 400MHz to 2.5GHz, Low-Noise, SiGe Downconverter Mixers ABSOLUTE MAXIMUM RATINGS VCC to GND ..........................................................-0.3V to +6.0V RFIN Input Power (50Ω Source).....................................+10dBm LO Input Power (50Ω Source) ........................................+10dBm SHDN, IFOUT, RFIN to GND ......................-0.3V to (VCC + 0.3V) LO to GND..........................................(VCC - 1V) to (VCC + 0.3V) Continuous Power Dissipation (TA = +70°C) SOT23-6 (derate 8.7mW/°C above +70°C)..................696mW Operating Temperature Range ..........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +160°C Lead Temperature (soldering, 10sec) .............................+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. DC ELECTRICAL CHARACTERISTICS (VCC = +2.7V to +5.5V, SHDN = +2V, TA = TMIN to TMAX unless otherwise noted. Typical values are at VCC = +3V and TA = +25°C. Minimum and maximum values are guaranteed over temperature by design and characterization.) PARAMETER SYMBOL CONDITIONS MIN MAX2680 Operating Supply Current ICC Shutdown Supply Current ICC Shutdown Input Voltage High VIH Shutdown Input Voltage Low VIL Shutdown Input Bias Current ISHDN TYP MAX 5.0 7.7 MAX2681 8.7 12.7 MAX2682 15.0 21.8 0.05 5 SHDN = 0.5V 2.0 mA µA V 0.5 0 < SHDN < VCC UNITS 0.2 V µA AC ELECTRICAL CHARACTERISTICS (MAX2680/1/2 EV Kit, VCC = SHDN = +3.0V, TA = +25°C, unless otherwise noted. RFIN and IFOUT matched to 50Ω. PLO = -5dBm, PRFIN = -25dBm.) PARAMETER CONDITIONS MIN TYP MAX UNITS MAX2680 RF Frequency Range (Notes 1, 2) 400 2500 MHz LO Frequency Range (Notes 1, 2) 400 2500 MHz IF Frequency Range (Notes 1, 2) 10 500 MHz fRF = 400MHz, fLO = 445MHz, fIF = 45MHz Conversion Power Gain Gain Variation Over Temperature Input Third-Order Intercept Point (Note 3) Noise Figure (Single Sideband) 7.3 fRF = 900MHz, fLO = 970MHz, fIF = 70MHz fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz (Note 1) 11.6 5.7 7.6 fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz 7.0 fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz, TA = TMIN to TMAX (Note 1) 1.9 fRF = 900MHz, 901MHz, fLO = 970MHz, fIF = 70MHz -12.9 fRF = 1950MHz, 1951MHz, fLO = 1880MHz, fIF = 70MHz -8.2 fRF = 2450MHz, 2451MHz, fLO = 2210MHz, fIF = 240MHz -6.9 fRF = 900MHz, fLO = 970MHz, fIF = 70MHz 6.3 8.6 2.4 dB dB dBm fRF = 1950MHz, fLO = 2020MHz, fIF = 70MHz 8.3 fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz 11.7 LO Input VSWR 50Ω source impedance 1.5:1 LO Leakage at IFOUT Port fLO = 1880MHz -22 dBm LO Leakage at RFIN Port fLO = 1880MHz -26 dBm IF/2 Spurious Response fRF = 1915MHz, fLO = 1880MHz, fIF = 70MHz (Note 4) -51 dBm 2 _______________________________________________________________________________________ dB 400MHz to 2.5GHz, Low-Noise, SiGe Downconverter Mixers (MAX2680/1/2 EV Kit, VCC = SHDN = +3.0V, TA = +25°C, unless otherwise noted. RFIN and IFOUT matched to 50Ω. PLO = -5dBm, PRFIN = -25dBm.) PARAMETER CONDITIONS MIN TYP MAX UNITS MAX2681 RF Frequency Range (Notes 1, 2) 400 2500 MHz LO Frequency Range (Notes 1, 2) 400 2500 MHz IF Frequency Range (Notes 1, 2) 10 500 MHz fRF = 400MHz, fLO = 445MHz, fIF = 45MHz Conversion Power Gain Gain Variation Over Temperature Input Third-Order Intercept Point (Note 3) 11.0 fRF = 900MHz, fLO = 970MHz, fIF = 70MHz fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz (Note 1) 14.2 6.7 8.4 fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz 7.7 fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz, TA = TMIN to TMAX (Note 1) 1.7 fRF = 900MHz, 901MHz, fLO = 970MHz, fIF = 70MHz -6.1 fRF = 1950MHz, 1951MHz, fLO = 1880MHz, fIF = 70MHz +0.5 fRF = 2450MHz, 2451MHz, fLO = 2210MHz, fIF = 240MHz +1.0 9.4 2.3 dB dB dBm fRF = 900MHz, fLO = 970MHz, fIF = 70MHz 7.0 fRF = 1950MHz, fLO = 2020MHz, fIF = 70MHz 11.1 fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz 12.7 LO Input VSWR 50Ω source impedance 1.5:1 LO Leakage at IFOUT Port fLO = 1880MHz -23 dBm LO Leakage at RFIN Port fLO = 1880MHz -27 dBm IF/2 Spurious Response fRF = 1915MHz, fLO = 1880MHz, fIF = 70MHz (Note 4) -65 dBm Noise Figure (Single Sideband) dB MAX2682 RF Frequency Range (Notes 1, 2) 400 2500 MHz LO Frequency Range (Notes 1, 2) 400 2500 MHz IF Frequency Range (Notes 1, 2) 10 500 MHz Conversion Power Gain Gain Variation Over Temperature Input Third-Order Intercept Point (Note 3) Noise Figure (Single Sideband) fRF = 400MHz, fLO = 445MHz, fIF = 45MHz 13.4 fRF = 900MHz, fLO = 970MHz, fIF = 70MHz 14.7 fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz (Note 1) 8.7 10.4 fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz 7.9 fRF = 1950MHz, fLO = 1880MHz, fIF = 70MHz, TA = TMIN to TMAX (Note 1) 2.1 fRF = 900MHz, 901MHz, fLO = 970MHz, fIF = 70MHz -1.8 fRF = 1950MHz, 1951MHz, fLO = 1880MHz, fIF = 70MHz +4.4 fRF = 2450MHz, 2451MHz, fLO = 2210MHz, fIF = 240MHz +3.2 fRF = 900MHz, fLO = 970MHz, fIF = 70MHz 6.5 fRF = 1950MHz, fLO = 2020MHz, fIF = 70MHz 10.2 fRF = 2450MHz, fLO = 2210MHz, fIF = 240MHz 13.4 11.7 3.2 dB dB dBm dB _______________________________________________________________________________________ 3 MAX2680/MAX2681/MAX2682 AC ELECTRICAL CHARACTERISTICS (continued) AC ELECTRICAL CHARACTERISTICS (continued) (MAX2680/1/2 EV Kit, VCC = SHDN = +3.0V, TA = +25°C, unless otherwise noted. RFIN and IFOUT matched to 50Ω. PLO = -5dBm, PRFIN = -25dBm.) PARAMETER CONDITIONS MIN TYP MAX UNITS LO Input VSWR 50Ω source impedance LO Leakage at IFOUT Port fLO = 1880MHz -23 dBm LO Leakage at RFIN Port fLO = 1880MHz -27 dBm IF/2 Spurious Response fRF = 1915MHz, fLO = 1880MHz, fIF = 70MHz (Note 4) -61 dBm Note 1: Note 2: Note 3: Note 4: 1.5:1 Guaranteed by design and characterization. Operation outside of this specification is possible, but performance is not characterized and is not guaranteed. Two input tones at -25dBm per tone. This spurious response is caused by a higher-order mixing product (2x2). Specified RF frequency is applied and IF output power is observed at the desired IF frequency (70MHz). Typical Operating Characteristics (Typical Operating Circuit, VCC = SHDN = +3.0V, PRFIN = -25dBm, PLO = -5dBm, TA = +25°C, unless otherwise noted.) TA = +85°C TA = +25°C 5 4 TA = -40°C TA = +85°C 9 8 TA = +25°C TA = -40°C 7 3 6 2 5 18 17 SHDN = VCC TA = +85°C 16 SUPPLY CURRENT (mA) 6 SHDN = VCC SUPPLY CURRENT (mA) SHDN = VCC MAX2682 SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX2680/1/2-02 10 MAX2680/1/2-01 7 MAX2681 SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX2680/1/2-03 MAX2680 SUPPLY CURRENT vs. SUPPLY VOLTAGE SUPPLY CURRENT (mA) MAX2680/MAX2681/MAX2682 400MHz to 2.5GHz, Low-Noise, SiGe Downconverter Mixers 15 14 13 TA = +25°C TA = -40°C 12 11 10 9 2.5 3.0 3.5 4.0 4.5 SUPPLY VOLTAGE (V) 4 5.0 5.5 8 2.5 3.0 3.5 4.0 4.5 SUPPLY VOLTAGE (V) 5.0 5.5 2.5 3.0 3.5 4.0 4.5 SUPPLY VOLTAGE (V) _______________________________________________________________________________________ 5.0 5.5 400MHz to 2.5GHz, Low-Noise, SiGe Downconverter Mixers 0.07 TA = +85°C TA = +25°C 0.06 0.05 0.04 TA = -40°C 0.03 0.02 0.05 0.04 3.5 4.0 4.5 5.0 TA = -40°C 0.03 0.02 0 3.0 TA = +85°C TA = +25°C 0.06 0.01 5.5 0.10 SHDN = GND 0.09 0.08 0.07 TA = +85°C TA = +25°C 0.06 0.05 0.04 0.03 TA = -40°C 0.02 0.01 0 2.5 3.0 3.5 4.0 4.5 5.0 2.5 5.5 3.0 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) MAX2680 CONVERSION POWER GAIN vs. LO POWER MAX2681 CONVERSION POWER GAIN vs. LO POWER MAX2682 CONVERSION POWER GAIN vs. LO POWER fRF = 1950MHz 9 fRF = 2450MHz 7 5 fRF fLO fIF 900MHz 970MHz 70MHz 1950MHz 1880MHz 70MHz 2450MHz 2210MHz 240MHz 3 1 12 10 fRF = 1950MHz 8 fRF = 2450MHz 6 fRF fIF fLO 900MHz 970MHz 70MHz 1950MHz 1880MHz 70MHz 2450MHz 2210MHz 240MHz 4 2 -14 -12 -10 -8 -6 -4 -2 12 fRF = 1950MHz 10 8 fRF = 2450MHz 6 fRF fIF fLO 900MHz 970MHz 70MHz 1950MHz 1880MHz 70MHz 2450MHz 2210MHz 240MHz 4 2 0 -14 0 fRF = 900MHz 14 0 -1 MAX2680/1/2-09 MAX2680/1/2-08 fRF = 900MHz 14 16 CONVERSION POWER GAIN (dB) 11 16 CONVERSION POWER GAIN (dB) MAX2680/1/2-07 fRF = 900MHz 13 -12 -10 -8 -6 -4 -2 0 -14 -12 -10 -8 -6 -4 -2 0 LO POWER (dBm) MAX2680 CONVERSION POWER GAIN vs. TEMPERATURE MAX2681 CONVERSION POWER GAIN vs. TEMPERATURE MAX2682 CONVERSION POWER GAIN vs. TEMPERATURE 16 16 17 12 10 fRF = 1950MHz 8 fRF = 2450MHz 6 fRF fIF fLO 900MHz 970MHz 70MHz 1950MHz 1880MHz 70MHz 2450MHz 2210MHz 240MHz 4 2 14 12 10 fRF = 1950MHz 8 fRF = 2450MHz 6 4 2 0 -20 0 20 40 60 TEMPERATURE (°C) 80 100 13 fRF = 1950MHz 11 9 7 fRF = 2450MHz 5 3 0 -40 fRF = 900MHz 15 CONVERSION POWER GAIN (dB) fRF = 900MHz CONVERSION POWER GAIN (dB) 14 fRF = 900MHz MAX2680/1/2-12 LO POWER (dBm) MAX2680/1/2-10 LO POWER (dBm) MAX2680/1/2-11 CONVERSION POWER GAIN (dB) 0.07 0 15 CONVERSION POWER GAIN (dB) 0.08 0.01 2.5 SHDN = GND 0.09 SHUTDOWN SUPPLY CURRENT (µA) 0.08 0.10 MAX2680/1/2-05 SHDN = GND SHUTDOWN SUPPLY CURRENT (µA) MAX2680/1/2-04 SHUTDOWN SUPPLY CURRENT (µA) 0.10 0.09 MAX2682 SHUTDOWN SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX2681 SHUTDOWN SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX2680/1/2-06 MAX2680 SHUTDOWN SUPPLY CURRENT vs. SUPPLY VOLTAGE 1 -40 -20 0 20 40 TEMPERATURE (°C) 60 80 100 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) _______________________________________________________________________________________ 5 MAX2680/MAX2681/MAX2682 Typical Operating Characteristics (continued) (Typical Operating Circuit, VCC = SHDN = +3.0V, PRFIN = -25dBm, PLO = -5dBm, TA = +25°C, unless otherwise noted.) 400MHz to 2.5GHz, Low-Noise, SiGe Downconverter Mixers MAX2680/MAX2681/MAX2682 Typical Operating Characteristics (continued) (Typical Operating Circuit, VCC = SHDN = +3.0V, PRFIN = -25dBm, PLO = -5dBm, TA = +25°C, unless otherwise noted.) MAX2681 INPUT IP3 vs. LO POWER -9 0 -1 -10 1 -3 -12 -10 -8 -6 -4 -2 0 0 -14 -12 -10 -8 -6 -4 -2 0 -14 -12 -10 -8 -6 -4 -2 LO POWER (dBm) LO POWER (dBm) LO POWER (dBm) MAX2680 NOISE FIGURE vs. LO POWER MAX2681 NOISE FIGURE vs. LO POWER MAX2682 NOISE FIGURE vs. LO POWER 8 fRF = 900MHz 6 14 fRF = 2450MHz 12 fRF = 1950MHz 10 8 6 fRF fLO fIF 900MHz 970MHz 70MHz 1950MHz 2020MHz 70MHz 2450MHz 2210MHz 70MHz 4 2 4 2 0 fRF = 900MHz -10 -8 -6 -4 -2 0 fRF = 2450MHz fRF = 1950MHz 10 5 0 -14 -12 -10 LO POWER (dBm) -8 -6 -4 -2 0 -14 -12 -10 LO POWER (dBm) MAX2680/1/2-19 0 300 250 -100 250 200 -200 150 -300 100 -400 -8 -6 -4 -2 0 LO POWER (dBm) MAX2681 RF PORT IMPEDANCE vs. RF FREQUENCY MAX2680 RF PORT IMPEDANCE vs. RF FREQUENCY 300 15 fRF = 900MHz fRF fIF fLO 900MHz 970MHz 70MHz 1950MHz 2020MHz 70MHz 2450MHz 2210MHz 70MHz 0 -12 fRF fIF fLO 900MHz 970MHz 70MHz 1950MHz 2020MHz 70MHz 2450MHz 2210MHz 70MHz 20 NOISE FIGURE (dB) fRF = 1950MHz 10 16 NOISE FIGURE (dB) fRF = 2450MHz 18 0 25 MAX2680/1/2-17 14 12 20 MAX2680/1/2-16 16 -14 3 2 fRF = 1950MHz, 1951MHz fLO = 1880MHz fIF = 70MHz PRFIN = -25dBm PER TONE -2 4 MAX2680/1/2-18 -8 -14 fRF = 1950MHz, 1951MHz fLO = 1880MHz fIF = 70MHz PRFIN = -25dBm PER TONE 6 INPUT IP3 (dBm) INPUT IP3 (dBm) INPUT IP3 (dBm) 1 5 -7 NOISE FIGURE (dB) 7 MAX2680/1/2-14 fRF = 1950MHz, 1951MHz fLO = 1880MHz fIF = 70MHz PRFIN = -25dBm PER TONE -6 2 MAX2680/1/2-13 -5 MAX2682 INPUT IP3 vs. LO POWER MAX2680/1/2-15 MAX2680 INPUT IP3 vs. LO POWER MAX2680/1/2-20 MAX2682 RF PORT IMPEDANCE vs. RF FREQUENCY 0 300 -100 250 MAX2680/1/2-21 0 50 REAL fLO = 970MHz PLO = -5dBm 0 0 500 1000 1500 RF FREQUENCY (MHz) 6 2000 -200 150 -300 100 -400 -500 50 -600 2500 0 fLO = 970MHz PLO = -5dBm 0 500 1000 1500 RF FREQUENCY (MHz) IMAGINARY -100 200 -200 150 -300 100 -400 REAL -500 50 -600 2500 0 2000 REAL fLO = 970MHz PLO = -5dBm 0 500 1000 1500 RF FREQUENCY (MHz) _______________________________________________________________________________________ 2000 -500 -600 2500 IMAGINARY IMPEDANCE (Ω) 200 REAL IMPEDANCE (Ω) IMAGINARY IMAGINARY IMPEDANCE (Ω) REAL IMPEDANCE (Ω) IMAGINARY IMPEDANCE (Ω) REAL IMPEDANCE (Ω) IMAGINARY 400MHz to 2.5GHz, Low-Noise, SiGe Downconverter Mixers -300 400 -400 REAL 0 100 200 300 400 -100 800 -200 600 -300 400 -400 -500 200 -600 0 500 -500 REAL 100 200 300 400 -100 600 -150 500 IMAGINARY 400 -200 300 -250 200 -300 REAL 100 -600 0 IF FREQUENCY (MHz) -400 0 +5 0 -10 -15 -20 -5 0 -10 -15 -20 -5 -10 -15 -20 -25 -30 -30 -30 -35 -35 -35 -40 -40 1320 1880 2440 -25 -40 200 3000 500 +5 -25 760 400 +10 RETURN LOSS (dB) RETURN LOSS (dB) -5 300 MAX2682 LO PORT RETURN LOSS MAX2680/1/2-26 0 200 IF FREQUENCY (MHz) +10 MAX2680/1/2-25 +5 760 1320 1880 2440 3000 200 760 1320 1880 2440 FREQUENCY (MHz) FREQUENCY (MHz) FREQUENCY (MHz) MAX2680 LO-to-IF AND LO-to-RF ISOLATION MAX2681 LO-to-IF AND LO-to-RF ISOLATION MAX2682 LO-to-IF AND LO-to-RF ISOLATION LO-to-IF ISOLATION 30 40 LO-to-IF ISOLATION 35 3000 35 MAX2680/1/2-29 35 MAX2680/1/2-28 200 100 MAX2681 LO PORT RETURN LOSS +10 -350 0 500 IF FREQUENCY (MHz) MAX2680 LO PORT RETURN LOSS LO-to-IF ISOLATION 30 30 20 ISOLATION (dB) 25 LO-to-RF ISOLATION 15 10 ISOLATION (dB) RETURN LOSS (dB) 700 MAX2680/1/2-27 0 1000 IMAGINARY MAX2680/1/2-24 0 fLO = 970MHz PLO = -5dBm -50 800 25 LO-to-RF ISOLATION 20 15 10 5 25 LO-to-RF ISOLATION 20 15 5 0 10 0 0 500 1000 1500 LO FREQUENCY (MHz) 2000 2500 0 500 1000 1500 LO FREQUENCY (MHz) 2000 2500 0 500 1000 1500 2000 2500 LO FREQUENCY (MHz) _______________________________________________________________________________________ 7 IMAGINARY IMPEDANCE (Ω) -100 600 200 0 fLO = 970MHz PLO = -5dBm -200 IMAGINARY MAX2680/1/2-23 1200 REAL IMPEDANCE (Ω) 800 ISOLATION (dB) REAL IMPEDANCE (Ω) 1000 0 MAX2682 IF PORT IMPEDANCE vs. IF FREQUENCY IMAGINARY IMPEDANCE (Ω) fLO = 970MHz PLO = -5dBm IMAGINARY IMPEDANCE (Ω) REAL IMPEDANCE (Ω) MAX2680/1/2-22 1200 MAX2681 IF PORT IMPEDANCE vs. IF FREQUENCY MAX2680/1/2-30 MAX2680 IF PORT IMPEDANCE vs. IF FREQUENCY MAX2680/MAX2681/MAX2682 Typical Operating Characteristics (continued) (Typical Operating Circuit, VCC = SHDN = +3.0V, PRFIN = -25dBm, PLO = -5dBm, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (Typical Operating Circuit, VCC = SHDN = +3.0V, PRFIN = -25dBm, PLO = -5dBm, TA = +25°C, unless otherwise noted.) IFOUT 50mV/ div MAX2680/1/2-32 SHDN 2V/div SHDN 2V/div Z1 = 39pF 500ns/div SHDN 2V/div IFOUT 50mV/ div IFOUT 50mV/ div Z1 = 39pF MAX2682 TURN-OFF/ON CHARACTERISTICS MAX2681 TURN-OFF/ON CHARACTERISTICS MAX2680/1/2-33 MAX2680 TURN-OFF/ON CHARACTERISTICS MAX2680/1/2-31 MAX2680/MAX2681/MAX2682 400MHz to 2.5GHz, Low-Noise, SiGe Downconverter Mixers Z2 = 39pF 500ns/div 500ns/div Pin Description 8 PIN NAME FUNCTION 1 LO 2 GND Mixer Ground. Connect to the ground plane with a low-inductance connection. 3 RFIN Radio Frequency Input. AC-couple to this pin with a DC-blocking capacitor. Nominal DC voltage is 1.5V. See Applications Information section for details on impedance matching. 4 IFOUT Intermediate Frequency Output. Open-collector output requires an inductor to VCC. AC-couple to this pin with a DC-blocking capacitor. See Applications Information section for details on impedance matching. 5 VCC 6 SHDN Local-Oscillator Input. Apply a local-oscillator signal with an amplitude of -10dBm to 0 (50Ω source). ACcouple this pin to the oscillator with a DC-blocking capacitor. Nominal DC voltage is VCC - 0.4V. Supply Voltage Input, +2.7V to +5.5V. Bypass with a capacitor to the ground plane. Capacitor value depends upon desired operating frequency. Active-Low Shutdown. Drive low to disable all device functions and reduce the supply current to less than 5µA. For normal operation, drive high or connect to VCC. _______________________________________________________________________________________ 400MHz to 2.5GHz, Low-Noise, SiGe Downconverter Mixers The MAX2680/MAX2681/MAX2682 are 400MHz to 2.5GHz, silicon-germanium, double-balanced downconverter mixers. They are designed to provide optimum linearity performance for a specified supply current. They consist of a double-balanced Gilbert-cell mixer with single-ended RF, LO, and IF port connections. An on-chip bias cell provides a low-power shutdown feature. Consult the Selector Guide for device features and comparison. Applications Information IF Output The IF output frequency range extends from 10MHz to 500MHz. IFOUT is a high-impedance, open-collector output that requires an external inductor to VCC for proper biasing. For optimum performance, the IF port requires an impedance-matching network. The configuration and values for the matching network is dependent upon the frequency and desired output impedance. For assistance in choosing components for optimal performance, refer to Tables 3 and 4 as well as the IF Port Impedance vs. IF Frequency graph in the Typical Operating Characteristics. Local-Oscillator (LO) Input Power-Supply and SHDN Bypassing The LO input is a single-ended broadband port with a typical input VSWR of better than 2.0:1 from 400MHz to 2.5GHz. The LO signal is mixed with the RF input signal, and the resulting downconverted output appears at IFOUT. AC-couple LO with a capacitor. Drive the LO port with a signal ranging from -10dBm to 0 (50Ω source). Proper attention to voltage supply bypassing is essential for high-frequency RF circuit stability. Bypass VCC with a 10µF capacitor in parallel with a 1000pF capacitor. Use separate vias to the ground plane for each of the bypass capacitors and minimize trace length to reduce inductance. Use separate vias to the ground plane for each ground pin. Use low-inductance ground connections. Decouple SHDN with a 1000pF capacitor to ground to minimize noise on the internal bias cell. Use a series resistor (typically 100Ω) to reduce coupling of high-frequency signals into the SHDN pin. RF Input The RF input frequency range is 400MHz to 2.5GHz. The RF input requires an impedance-matching network as well as a DC-blocking capacitor that can be part of the matching network. Consult Tables 1 and 2, as well as the RF Port Impedance vs. RF Frequency graph in the Typical Operating Characteristics for information on matching. Table 1. RFIN Port Impedance Layout Issues A well designed PC board is an essential part of an RF circuit. For best performance, pay attention to powersupply issues as well as to the layout of the RFIN and IFOUT impedance-matching network. FREQUENCY PART 400MHz 900MHz 1950MHz 2450MHz MAX2680 179-j356 54-j179 32-j94 33-j73 MAX2681 209-j332 75-j188 34-j108 33-j86 MAX2682 206-j306 78-j182 34-j106 29-j86 Table 2. RF Input Impedance-Matching Component Values FREQUENCY MATCHING COMPONENTS MAX2680 1950 MHz MAX2681 400 MHz 900 MHz 2450 MHz Z1 86nH 270pF 1.5pF Z2 270pF 22nH 270pF Z3 Open Open 1.8nH 1.8nH 1950 MHz MAX2682 400 MHz 900 MHz 2450 MHz 400 MHz 900 MHz 1950 MHz 2450 MHz Short 68nH 270pF 1.5pF Short 68nH 1.5pF Short Short 270pF 270pF 18nH 270pF 270pF 270pF 270pF 270pF 270pF 0.5pF Open 1.8nH 2.2nH 0.5pF 10nH 2.2nH 1.2nH Note: Z1, Z2, and Z3 are found in the Typical Operating Circuit. _______________________________________________________________________________________ 9 MAX2680/MAX2681/MAX2682 Detailed Description MAX2680/MAX2681/MAX2682 400MHz to 2.5GHz, Low-Noise, SiGe Downconverter Mixers Power-Supply Layout Table 3. IFOUT Port Impedance To minimize coupling between different sections of the IC, the ideal power-supply layout is a star configuration with a large decoupling capacitor at a central V CC node. The V CC traces branch out from this central node, each going to a separate VCC node on the PC board. At the end of each trace is a bypass capacitor that has low ESR at the RF frequency of operation. This arrangement provides local decoupling at the VCC pin. At high frequencies, any signal leaking out of one supply pin sees a relatively high impedance (formed by the VCC trace inductance) to the central VCC node, and an even higher impedance to any other supply pin, as well as a low impedance to ground through the bypass capacitor. FREQUENCY PART 45MHz 70MHz 240MHz MAX2680 960-j372 803-j785 186-j397 MAX2681 934-j373 746-j526 161-j375 MAX2682 670-j216 578-j299 175-j296 Table 4. IF Output Impedance-Matching Components FREQUENCY MATCHING COMPONENT 45MHz 70MHz 240MHz L1 390nH 330nH 82nH C2 39pF 15pF 3pF R1 250Ω Open Open Impedance-Matching Network Layout The RFIN and IFOUT impedance-matching networks are very sensitive to layout-related parasitics. To minimize parasitic inductance, keep all traces short and place components as close as possible to the chip. To minimize parasitic capacitance, use cutouts in the ground plane (and any other plane) below the matching network components. However, avoid cutouts that are larger than necessary since they act as aperture antennas. Typical Operating Circuit C1 LO INPUT 1 SHDN LO 6 SHUTDOWN CONTROL C3 2 GND MAX2680 MAX2681 MAX2682 VCC 5 VCC +2.7V TO +5.5V L1 RF INPUT Z2 Z1 Z3 3 RFIN IFOUT C4 1000pF R1 C5 10µF IF OUTPUT 4 C2 THE VALUES OF MATCHING COMPONENTS C2, L1, R1, Z1, Z2, AND Z3 DEPEND ON THE IF AND RF FREQUENCY AND DOWNCONVERTER. SEE TABLES 2 AND 4. 10 ______________________________________________________________________________________ 400MHz to 2.5GHz, Low-Noise, SiGe Downconverter Mixers 6LSOT.EPS ______________________________________________________________________________________ 11 MAX2680/MAX2681/MAX2682 Package Information MAX2680/MAX2681/MAX2682 400MHz to 2.5GHz, Low-Noise, SiGe Downconverter Mixers NOTES 12 ______________________________________________________________________________________