19-1282; Rev 0; 10/97 KIT ATION EVALU E L B AVAILA Low-Noise, 2.5GHz Downconverter Mixer ____________________________Features 7.6dBm Input Third-Order Intercept Point The IF port is differential, which provides good linearity and low LO emissions, as well as providing compatibility with applications using differential IF filters, such as CDMA cellular phones. The mixer noise figure is 10dB at 900MHz. The MAX2690 draws 16mA at VCC = 3V and operates from a +2.7V to +5.5V supply. A logic-controlled shutdown mode reduces the supply current to less than 1A, making it ideal for battery-operated equipment. This device is offered in a miniature 10-pin MAX package. <1A Shutdown Mode ________________________Applications 2.45GHz Industrial-Scientific-Medical (ISM) Band Radios 10dB Downconverter Mixer Noise Figure 7.9dB Gain 400MHz to 2500MHz Wideband Operation Low Cost +2.7V to +5.5V Single-Supply Operation Ultra-Small 10-Pin MAX Package ______________Ordering Information PART MAX2690EUB TEMP. RANGE PIN-PACKAGE -40C to +85C 10 MAX Wireless Local Area Networks (WLANs) Personal Communications Systems (PCS) Code-Division Multiple Access (CDMA) Communications Systems Cellular and Cordless Phones Typical Operating Circuit appears at end of data sheet. Hand-Held Radios __________________Pin Configuration ________________Functional Diagram TOP VIEW TOP VIEW MAX2690 LGND 1 GND 2 RFIN 3 10 SHDN MAX2690 BIAS 10 SHDN GND 2 9 IFOUT+ 9 IFOUT+ 8 IFOUT- RFIN 3 8 IFOUT- RFBYP 4 7 GNDLO VCC 5 6 LO RFBYP 4 7 GNDLO VCC 5 6 LO MAX LGND 1 MAX ________________________________________________________________ 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 408-737-7600 ext. 3468. MAX2690 _______________General Description The MAX2690 is a miniature, low-noise, low-power downconverter mixer designed for use in portable consumer equipment. Signals at the RF input port are mixed with signals at the local-oscillator (LO) port using a double-balanced mixer. The RF port frequency range is 400MHz to 2500MHz. The LO port frequency range is 700MHz to 2500MHz. The IF frequency range is 10MHz to 500MHz, provided the LO and RF frequencies are chosen appropriately. MAX2690 Low-Noise, 2.5GHz Downconverter Mixer ABSOLUTE MAXIMUM RATINGS VCC to GND ...........................................................-0.3V to +6.0V RFIN Input Power..............................................................10dBm LO Input Power .................................................................10dBm SHDN Input Voltage ...................................-0.3V to (VCC + 0.3V) Continuous Power Dissipation 10-Pin MAX (derate 4.1mW/C above +70C) ............330mW Operating Temperature Range MAX2690EUB ...................................................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +165C Lead Temperature (soldering, 10sec) .............................+300C 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, no RF signals applied, LO = open, IFOUT+ = IFOUT- = VCC, SHDN = high, LGND = GND = GNDLO = 0V, TA = TMIN to TMAX. Typical values are at VCC = +3.0V and TA = +25C, unless otherwise noted. Minimum and maximum values are guaranteed by design and characterization over temperature.) PARAMETER CONDITIONS Operating Supply Current Shutdown Input Voltage High MIN TYP MAX UNITS 9.5 16 20.1 mA 2 V Shutdown Input Voltage Low Shutdown Supply Current Shutdown Input Bias Current 0.5 SHDN = 0V 0.4 SHDN = low 2 0V < SHDN < VCC -5 4 25 V A A AC ELECTRICAL CHARACTERISTICS (MAX2690 EV kit; VCC = +3.0V; PLO = -3dBm; PRF = -25dBm; SHDN = high; RFIN matched for 900MHz, 1.95GHz, and 2.45GHz as noted below. Inductor connected from LGND to GND = 39nH for 900MHz operation, 27nH for 1.95GHz operation, and 6.8nH for 2.45GHz operation. TA = +25C, unless otherwise noted.) PARAMETER Conversion Gain (Note 1) CONDITIONS fRF = 1.95GHz, fLO = 1.75GHz 6.4 fRF = 2.45GHz, fLO = 2.1GHz 4 fRF = 1.95GHz, TA = TMIN to TMAX (Note 2) Input Third-Order Intercept Two tones at -25dBm per tone, fRF2 = 1MHz above fRF 2 TYP 7.9 Gain Variation over Temperature Noise-Figure Single Sideband MIN fRF = 900MHz, fLO = 1.1GHz 0.6 fRF = 900MHz, fLO = 1.1GHz 7.6 fRF = 1.95GHz, fLO = 1.75GHz 5.3 fRF = 2.45GHz, fLO = 2.1GHz 4.3 fRF = 900MHz, fLO = 1.1GHz MAX UNITS dB 1.2 dB dBm 10 fRF = 1.95GHz, fLO = 1.75GHz 11.5 fRF = 2.45GHz, fLO = 2.1GHz 12 _______________________________________________________________________________________ dB Low-Noise, 2.5GHz Downconverter Mixer (MAX2690 EV kit; VCC = +3.0V; PLO = -3dBm; PRF = -25dBm; SHDN = high; RFIN matched for 900MHz, 1.95GHz, and 2.45GHz as noted below. Inductor connected from LGND to GND = 39nH for 900MHz operation, 27nH for 1.95GHz operation, and 6.8nH for 2.45GHz operation. TA = +25C, unless otherwise noted.) PARAMETER LO Emission at IF Port LO Emission at RF Port IF/2 Spurious Response (Note 3) CONDITIONS MIN TYP fRF = 900MHz, fLO = 1.1GHz -32 fRF = 1.95GHz, fLO = 1.75GHz -32 fRF = 2.45GHz, fLO = 2.1GHz -28 fRF = 900MHz, fLO = 1.1GHz -30 fRF = 1.95GHz, fLO = 1.75GHz -27 fRF = 2.45GHz, fLO = 2.1GHz -25 RF input = -15dBm fRF = 1.0GHz, fLO = 1.1GHz -74 fRF = 1.85GHz, fLO = 1.75GHz -62 fRF = 2.275GHz, fLO = 2.1GHz -56 MAX UNITS dBm dBm dBm Turn-On Time (Note 4) 1 s Turn-Off Time (Note 4) 1.6 s Note 1: Consult the Applications Information section for information on designing a matching network. Note 2: Guaranteed by design and characterization. Note 3: 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 (200MHz for fRF = 900MHz, or 1.95GHz, and 350MHz for fRF = 2.45GHz). Note 4: From the time SHDN goes high to the time ICC reaches 90% of its final value (on), or from the time SHDN goes low to the time ICC drops below 10A (off). _______________________________________________________________________________________ 3 MAX2690 AC ELECTRICAL CHARACTERISTICS (continued) __________________________________________Typical Operating Characteristics (MAX2690 EV kit, VCC = +3.0V, PLO = -3dBm, PRF = -25dBm, fRF = 1.95GHz, fIF = 200MHz, SHDN = high, TA = +25C, unless otherwise noted.) 15 TA = +85C 13 11 9 TA = -40C 0.6 0.4 5.4 5.2 5.0 4.8 4.6 4.4 4.2 4.0 2.7 3.0 3.3 3.6 3.9 4.2 4.5 4.8 5.1 5.4 5.7 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) IF FREQUENCY (MHz) CONVERSION GAIN vs. RF FREQUENCY NOISE FIGURE vs. RF FREQUENCY AND TEMPERATURE RF PORT IMPEDANCE vs. FREQUENCY 12 fIF = 200MHz 2 0 -2 10 TA = +85C TA = +25C 8 TA = -40C 6 4 fIF = 350MHz 2 -4 -6 fRF (MHz) fIF (MHz) 900 1950 2450 200 200 350 1500 2000 2500 3000 1000 1500 2000 2500 RF FREQUENCY (MHz) CONVERSION GAIN vs. LO POWER GAIN AND LINEARITY vs. LGND INDUCTOR VALUE MAX2690toc07 fRF = 900MHz, fIF = 200MHz 6 4 2 fRF = 1950MHz, fIF = 200MHz 0 fRF = 2450MHz, fIF = 350MHz -15 -13 -11 -9 -7 -5 -3 LO POWER (dBm) -1 1 3 5 MAX2690toc06 0 -50 -100 100 IMAGINARY 80 -150 -200 60 -250 40 -300 -350 14 fRF = 1.95GHz 12 500 3000 1000 1500 2000 2500 FREQUENCY (MHz) LO PORT S11 vs. FREQUENCY 10 0 OIP3 10 IIP3 GAIN 8 6 4 -10 -20 -30 -40 0 -6 350 20 2 -4 300 0 500 RF FREQUENCY (MHz) 10 250 REAL LO PORT S11 (dB) 1000 GAIN AND LINEARITY (dB or dBm) 500 200 120 0 0 150 MAX2690toc09 NOISE FIGURE (dB) 4 100 140 REAL IMPEDANCE () fIF = 200MHz 6 50 MAX2690toc05 14 MAX2690toc04 8 CONVERSION GAIN (dB) 1.0 0.8 5.6 2.7 3.0 3.3 3.6 3.9 4.2 4.5 4.8 5.1 5.4 5.7 10 4 TA = +25C 0 5 -2 TA = +85C 1.2 fRF = 2.45GHz 5.8 0.2 7 8 1.4 -50 0 12 27 LGND INDUCTOR VALUE (nH) 47 0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3.0 FREQUENCY (GHz) _______________________________________________________________________________________ IMAGINARY IMPEDANCE () 17 6.0 MAX2690toc08 SUPPLY CURRENT (mA) TA = -40C 19 SHDN = 0V CONVERSION GAIN (dB) TA = +25C 1.6 MAX2690toc02 23 SHUTDOWN SUPPLY CURRENT (A) MAX2690toc01 25 21 CONVERSION GAIN vs. IF FREQUENCY SHUTDOWN SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX2690toc03 SUPPLY CURRENT vs. SUPPLY VOLTAGE GAIN (dB) MAX2690 Low-Noise, 2.5GHz Downconverter Mixer Low-Noise, 2.5GHz Downconverter Mixer CAPACITANCE 14 TA = +85C 6.5 TA = +25C 6.0 5.5 5.0 TA = -40C 4.5 4.0 1300 1700 2100 3.5 -40 12 3.0 10 2.5 8 2.0 RESISTANCE 6 1.5 4 1.0 2 0.5 0 0 2500 1 125 RF FREQUENCY (MHz) 250 375 fRF = 900MHz IF = 200MHz -4 -5 fIF (MHz) 900 1950 2450 200 200 350 0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3.0 9 8 fRF = 900MHz, fIF = 200MHz 7 fRF = 1.95GHz, fIF = 200MHz 6 5 fRF = 2.95GHz, fIF = 350MHz 4 3 1 1500 2000 2500 0 3000 2.0 2.5 3.0 3.5 4.0 4.5 5.0 RF FREQUENCY (MHz) VCC (V) INPUT IP3 vs. SUPPLY VOLTAGE CONVERSION GAIN vs. TEMPERATURE 7 6 5 4 fRF = 2450MHz, fIF = 350MHz fRF = 1950MHz, fIF = 200MHz fRF = 900MHz, fIF = 200MHz 8 CONVERSION GAIN (dB) 8 5.5 9 MAX2690toc15 fRF = 900MHz, fIF = 200MHz 3 LO + RF -100 2 10 9 2LO - RF -90 10 -8 1000 -70 FREQUENCY (GHz) CONVERSION GAIN (dB) TA = -40C 500 RF 500 MAX2690toc13 -3 -7 3LO - RF -60 CONVERSION GAIN vs. SUPPLY VOLTAGE TA = +85C TA = +25C fRF (MHz) 2LO -50 FREQUENCY (MHz) -2 -6 LO = 1.1GHz -80 INPUT 1dB COMPRESSION vs. RF FREQUENCY AND TEMPERATURE INPUT 1dB COMPRESSION (dBm) 900 -30 7 6.0 MAX2690toc16 7.0 4.0 MAX2690toc14 RESISTANCE (k) 7.5 -20 MAX2690toc12 16 4.5 OUTPUT POWER (dBm) 8.0 IF PORT OUTPUT SPECTRUM MAX2690toc11 18 MAX2690toc10 fRF2 = 1MHz ABOVE fRF 8.5 INPUT IP3 (dBm) INPUT THIRD-ORDER INTERCEPT (dBm) 9.0 SINGLE-ENDED IF PORT EQUIVALENT SHUNT RC NETWORK CAPACITANCE (pF) IIP3 vs. RF FREQUENCY AND TEMPERATURE fRF = 1950MHz, fIF = 200MHz 6 5 fRF = 2450MHz, fIF = 350MHz 4 3 2 2 1 1 0 0 2.0 2.5 3.0 3.5 4.0 VCC (V) 4.5 5.0 5.5 6.0 -40 -20 0 20 40 60 80 100 TEMPERATURE (C) _______________________________________________________________________________________ 5 MAX2690 ____________________________Typical Operating Characteristics (continued) (MAX2690 EV kit, VCC = +3.0V, PLO = -3dBm, PRF = -25dBm, fRF = 1.95GHz, fIF = 200MHz, SHDN = high, TA = +25C, unless otherwise noted.) ________________________________________________Key Specification Statistics (MAX2690 EV kit, VCC = +3.0V, PLO = -3dBm, PRF = -25dBm, fRF = 1.95GHz, fIF = 200MHz, SHDN = high, TA = +25C, unless otherwise noted.) Histograms represent measured data from a 30-unit sample taken from one wafer lot. The Gaussian curve is calculated for the measured data's mean and standard deviation and is scaled to account for process variations (the listed mean and standard deviation are from the scaled distribution, as plotted). GAIN (+85C) INPUT IP3 (+85C) 15 0.8 12 0.6 9 0.4 6 0.2 3 0 0 4.6 5.4 6.2 7.0 0.8 12 0.6 9 0.4 6 0.2 3 0 0 7.8 3.4 4.2 GAIN (dB) 1.4 28 1.2 24 1.0 20 0.8 16 0.6 12 0.4 8 0.2 4 6.4 6.8 7.2 7.6 MAX2690toc20 x = 5.25dB = 0.390dB 1.0 0.6 12 0.4 8 0.2 4 0 2.9 8.0 3.7 15 0.50 10 0.25 5 0 0 7.0 7.4 GAIN (dB) 6 7.8 8.2 8.6 PROBABILITY DENSITY FUNCTION 0.75 NO. OF UNITS 25 20 6.6 6.1 6.9 7.7 MAX2690toc22 1.2 30 1.00 6.2 5.3 INPUT IP3 (-40C) x = 7.00dB = 0.272dB 5.8 4.5 INPUT IP3 (dBm) MAX2690toc21 1.25 20 16 GAIN (-40C) 1.50 24 0.8 GAIN (dB) 5.4 7.4 0 0 0 6.0 6.6 1.2 NO. OF UNITS PROBABILITY DENSITY FUNCTION x = 6.37dB = 0.257dB 32 PROBABILITY DENSITY FUNCTION MAX2690toc19 5.6 5.8 INPUT IP3 (+25C) GAIN (+25C) 5.2 5.0 INPUT IP3 (dBm) 1.6 4.8 15 N0. OF UNITS 3.8 1.0 18 x = 4.63dB = 0.347dB 1.0 18 15 0.8 12 0.6 9 0.4 6 0.2 3 0 0 2.0 2.8 3.6 4.4 5.2 INPUT IP3 (dBm) _______________________________________________________________________________________ 6.0 6.8 N0. OF UNITS 3.0 x = 5.55dB = 0.347dB NO. OF UNITS 1.0 MAX2690toc18 1.2 N0. OF UNITS PROBABILITY DENSITY FUNCTION x = 5.76dB = 0.338dB 18 PROBABILITY DENSITY FUNCTION MAX2690toc17 1.2 PROBABILITY DENSITY FUNCTION MAX2690 Low-Noise, 2.5GHz Downconverter Mixer Low-Noise, 2.5GHz Downconverter Mixer PIN NAME FUNCTION 1 LGND Inductive Degeneration Pin. For maximum linearity, connect LGND directly to ground with no series inductance. Trade off linearity for gain by increasing the series inductance from LGND to ground. See the Applications Information section for more information. 2 GND RF Ground. This pin must have a separate via to the ground plane, as close to the pin as possible to minimize inductance. 3 RFIN RF Input Port. RF Input of Downconverter Mixer. See the Applications Information section for details on matching to RFIN. 4 RFBYP 5 VCC Supply-Voltage Input, +2.7V to +5.5V. Connect 0.1F and 1000pF capacitors (in parallel) between VCC and GND. 6 LO Local-Oscillator Input. LO should be AC coupled and presents a 50 load impedance. See the Applications Information section for more information. 7 GNDLO Ground for the LO Port. This pin must have its own via to the ground plane, as close as possible to the pin to minimize inductance. 8 IFOUT- Differential IF Inverting Output. IFOUT- is an open-collector output and must be pulled up to VCC with an external inductor for proper biasing. A resistor in parallel with the inductor may also be used to set a terminating impedance. See the Typical Operating Characteristics section for a plot of IF port characteristics vs. frequency (see plot titled Single-Ended IF Port Equivalent Shunt RC Network). 9 IFOUT+ Differential IF Noninverting Output. IFOUT+ is an open-collector output and must be pulled up to VCC with an external inductor for proper biasing. A resistor in parallel with the inductor may also be used to set a terminating impedance. See the Typical Operating Characteristics section for a plot of IF port characteristics vs. frequency (see plot titled Single-Ended IF Port Equivalent Shunt RC Network). 10 SHDN Active-Low Shutdown Input. A digital logic-low level at SHDN deactivates all part functions and reduces the supply current to typically 0.4A. RF Bypassing Capacitor Pin. Bypass RFBYP with an appropriate-value capacitor (typically 1000pF) to ground. _______________Detailed Description The MAX2690 is a 2.5GHz, double-balanced downconverter mixer designed to provide optimum intermodulation performance for a given supply current. It consists of a double-balanced Gilbert-cell mixer with singleended RF and LO port connections, and a differential IF port. An on-chip bias cell provides a low-power shutdown feature. RF Input The RFIN and RFBYP pins form the MAX2690's RF input. The single-ended RF input signal is applied to the RFIN pin (refer to the RF Port Impedance vs. Frequency graph in the Typical Operating Characteristics). The RFBYP pin should be AC grounded typically with a 1000pF capacitor. This capacitor value should present a low impedance at both the RF and IF frequencies. IF Output The IFOUT+ and IFOUT- pins form the MAX2690's differential open-collector IF output. The IF output is coupled to the load using shunt inductors to VCC and series capacitors to the load. Most applications use a resistive termination of 500 (typical) resistors in parallel with the pull-up inductors to set a terminating impedance. The part's conversion gain has been specified with the resistors in place (using the output network on the MAX2690 EV kit), accounting for a 3dB loss due to the resistors. Therefore, it is possible to achieve an increase in gain with a properly designed matching network. However, the resistors provide for minimum passband ripple when this port is connected to typical IF filters. Bias The bias cell includes compensation circuitry to minimize conversion-gain variations over temperature as well as shutdown control circuitry. The SHDN pin can be used to disable all functions and reduce supply current to typically 0.4A. _______________________________________________________________________________________ 7 MAX2690 ______________________________________________________________Pin Description MAX2690 Low-Noise, 2.5GHz Downconverter Mixer __________Applications Information plane. Low-inductance ground connections and controlled-impedance lines should be used in the layout. Local-Oscillator (LO) Input To minimize noise on the internal bias cell, SHDN should be decoupled with a 1000pF capacitor to ground. A series resistor (typically 100) can also be used to reduce high-frequency signals coupling into the SHDN pin. The LO input is a single-ended broadband 50 input with a return loss of better than 10dB from 900MHz to 3GHz, improving at high frequency. For lower-frequency LO operation, a shunt resistor can be used to improve the LO port match (see the Typical Operating Circuit for more information). AC couple to LO. The LO signal is mixed with the input RF signal, and the resulting downconverted output appears on the IFOUT+ and IFOUT- pins. RF Input The typical RF input frequency range is 400MHz to 2.5GHz. For optimum performance, the RF input requires an impedance-matching network. Consult Table 1 as well as the RF Port Impedance vs. Frequency graph in the Typical Operating Characteristics. Table 1. RF Input Impedance ______________________Layout Issues FREQUENCY PART 900MHz 1.95GHz 2.45GHz 45 - j 219 20 - j 110 18 - j 85 Equivalent Shunt R 1100 630 400 Equivalent Shunt C 0.7pF 0.7pF 0.7pF Series Z IF Output The IF output frequency range is typically 10MHz to 500MHz. The IFOUT+ and IFOUT- pins require external inductors to VCC for proper biasing. These outputs are high-impedance open collectors. In many applications, the biasing inductors have resistors in parallel with them to set an output impedance. Alternatively, a resistor between IFOUT+ and IFOUT- may be used. Consult the Typical Operating Characteristics section for more information. For single-ended operation, the IFOUT- pin can be tied directly to VCC. Power Supply and Bypassing Proper attention to supply bypassing is essential for a high-frequency RF circuit. VCC (pin 5) must be properly bypassed with a 0.1F capacitor in parallel with 1000pF to ground. Separate vias to the ground plane are needed for each of the bypass capacitors, as well as minimal trace length to reduce inductance. Each ground pin should have a separate via to the ground 8 Inductive Degeneration Pin (LGND) A series inductor is typically connected from LGND to GND. Adjusting the value of this inductor allows the MAX2690 to be set to the optimum gain and linearity point for a particular application. A short from LGND to ground provides maximum linearity. Increasing the inductor value trades off linearity for gain. A large inductor provides maximum gain. See the Typical Operating Characteristics for a graph of conversion gain and linearity for several inductor values. The inductor's self-resonant frequency (SRF) should be as close as possible to or above the desired RF frequency for optimal performance. A well-designed PC board is an essential part of an RF circuit. For best performance, pay attention to powersupply issues as well as the layout of the RFIN matching network. Power-Supply Layout To minimize coupling between different sections of the IC, the ideal power-supply layout is a star configuration, which has a large decoupling capacitor at a central VCC node. The VCC traces branch out from this node, each going to a separate VCC node in the MAX2690 circuit. At the end of each of these traces is a bypass capacitor that is good at the RF frequency of interest. This arrangement provides local decoupling at each VCC pin. At high frequencies, any signal leaking out 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. Matching-Network Layout The layout of the RFIN matching network can be very sensitive to parasitic circuit elements. To minimize parasitic inductance, keep all traces short, and place components as close to the chip as possible. To minimize parasitic capacitance, a cut-out in the ground plane (and any other planes) below the matching network components can be used. _______________________________________________________________________________________ Low-Noise, 2.5GHz Downconverter Mixer 27nH 1 LGND SHDN 100 10 1000pF 1pF RF INPUT 3.3nH 3 1pF MAX2690 220nH 500 IFOUT+ RFBYP 1000pF VCC IFOUT5 0.1pF VCC RFIN 0.5pF 4 RF = 1.95GHz SHUTDOWN CONTROL VCC 1000pF GND 2 LO 6 LO INPUT ROPTIONAL (SEE TEXT) 1000pF GNDLO 1000pF 9 IF OUTPUT TO IF FILTER 8 500 IF = 200MHz 220nH 7 VCC 1000pF _______________________________________________________________________________________ 9 MAX2690 ___________________________________________________Typical Operating Circuit ________________________________________________________Package Information 10LUMAXB.EPS MAX2690 Low-Noise, 2.5GHz Downconverter Mixer 10 ______________________________________________________________________________________