19-0705 Rev 0; 1/07 Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch The MAX9985 high-linearity, dual-channel downconversion mixer is designed to provide approximately 6dB gain, +28.5dBm of IIP3, and 10.5dB of noise figure (NF) ideal for diversity receiver applications. With a 700MHz to 1000MHz RF frequency range and a 570MHz to 865MHz LO frequency range, this mixer is ideal for lowside LO injection architectures. In addition, the broad frequency range makes the MAX9985 ideal for GSM 850/950, 2G/2.5G EDGE, WCDMA, cdma2000®, and iDEN® base-station applications. The MAX9985 dual-channel downconverter achieves a high level of component integration. The MAX9985 integrates two double-balanced active mixer cores, two LO buffers, a dual-input LO selectable switch, and a pair of differential IF output amplifiers. In addition, integrated on-chip baluns at the RF and LO ports allow for singleended RF and single-ended LO inputs. The MAX9985 requires a typical 0dBm LO drive. Supply current is adjustable up to 400mA. The MAX9985 is available in a 36-pin thin QFN package (6mm x 6mm) with an exposed paddle. Electrical performance is guaranteed over the extended temperature range, from TC = -40°C to +85°C. Applications 850MHz WCDMA Base Stations Features 700MHz to 1000MHz RF Frequency Range 570MHz to 865MHz LO Frequency Range 50MHz to 250MHz IF Frequency Range 6dB Typical Conversion Gain 10.5dB Typical Noise Figure +28.5dBm Typical Input IP3 +16.2dBm Typical Input 1dB Compression Point 77dBc Typical 2RF-2LO Spurious Rejection at PRF = -10dBm Dual Channels Ideal for Diversity Receiver Applications 47dB Typical Channel-to-Channel Isolation -3dBm to +3dBm LO Drive Integrated LO Buffer Internal RF and LO Baluns for Single-Ended Inputs Built-In SPDT LO Switch with 43dB LO1-to-LO2 Isolation and 50ns Switching Time Pin-Compatible with MAX9995/MAX9995A 1700MHz to 2200MHz Mixers Lead-Free Package Available GSM 850/GSM 950, 2G/2.5G EDGE Base Stations cdmaOne™ and cdma2000 Base Stations iDEN Base Stations Fixed Broadband Wireless Access Ordering Information PART PIN-PACKAGE MAX9985ETX -40°C to +85°C 36 Thin QFN-EP* T3666-2 (6mm x 6mm) MAX9985ETX-T -40°C to +85°C 36 Thin QFN-EP* (6mm x 6mm), T3666-2 T/R MAX9985ETX+ -40°C to +85°C 36 Thin QFN-EP* (6mm x 6mm), T3666-2 lead free, bulk MAX9985ETX+T -40°C to +85°C 36 Thin QFN-EP* (6mm x 6mm), T3666-2 lead free, T/R Wireless Local Loop Private Mobile Radios Military Systems Digital and Spread-Spectrum Communication Systems Microwave Links cdma2000 is a registered trademark of Telecommunications Industry Association. iDEN is a registered trademark of Motorola, Inc. cdmaOne is a trademark of CDMA Development Group. PKG CODE TEMP RANGE *EP = Exposed paddle. T = Tape-and-reel package. +Denotes lead-free and RoHS compliant. ________________________________________________________________ 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 MAX9985 General Description MAX9985 Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch ABSOLUTE MAXIMUM RATINGS VCC to GND ...........................................................-0.3V to +5.5V LO1, LO2 to GND ...............................................................±0.3V Any Other Pins to GND...............................-0.3V to (VCC + 0.3V) RFMAIN, RFDIV, and LO_ Input Power ..........................+20dBm RFMAIN, RFDIV Current (RF is DC shorted to GND through balun) ...............................................................................50mA Continuous Power Dissipation (TC = +70°C) (Note A) 36-Pin Thin QFN (derate 26mW/°C above +70°C) .........10.8W Operating Temperature Range ...........................-40°C to +85°C Maximum Junction Temperature Range..........................+150°C θJA .................................................................................+38°C/W θJC ...................................................................................7.4°C/W Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C Note A: TC is the temperature on the exposed paddle of the package. 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 (Using the Typical Application Circuit, no input RF or LO signals applied, VCC = 4.75V to 5.25V, TC = -40°C to +85°C. Typical values are at VCC = 5.0V, TC = +25°C, unless otherwise noted.) PARAMETER Supply Voltage Supply Current SYMBOL CONDITIONS VCC ICC MIN TYP MAX UNITS 4.75 V 5 5.25 Total supply current (see Table 1 for lower current settings) 400 440 VCC (pin 16) 80 VCC (pin 30) 80 IFM+/IFM- (total of both) 105 IFD+/IFD- (total of both) LOSEL Input High Voltage VIH LOSEL Input Low Voltage VIL LOSEL Input Current mA 105 2 IIH and IIL V -10 0.8 V +10 µA AC ELECTRICAL CHARACTERISTICS (Using the Typical Application Circuit, VCC = 4.75V to 5.25V, RF and LO ports are driven from 50Ω sources, PLO = -3dBm to +3dBm, PRF = -5dBm, fRF = 820MHz to 920MHz, fLO = 670MHz to 865MHz, fIF = 100MHz, fRF > fLO, TC = -40°C to +85°C. Typical values are at VCC = 5.0V, PRF = -5dBm, PLO = 0dBm, fRF = 870MHz, fLO = 770MHz, fIF = 100MHz, TC = +25°C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS RF Frequency fRF (Note 2) 700 1000 MHz LO Frequency fLO (Note 2) 570 865 MHz IF Frequency fIF IF matching components affect the IF frequency range (Note 2) 50 250 MHz +3 dBm 7.5 dB LO Drive PLO (Note 3) -3 Conversion Gain GC (Note 6) 4.5 Gain Variation over Temperature Conversion Gain Flatness 2 Flatness over any one of three frequency bands: fRF = 824MHz to 849MHz fRF = 869MHz to 894MHz fRF = 880MHz to 915MHz 6 -0.012 dB/°C ±0.1 dB _______________________________________________________________________________________ Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch (Using the Typical Application Circuit, VCC = 4.75V to 5.25V, RF and LO ports are driven from 50Ω sources, PLO = -3dBm to +3dBm, PRF = -5dBm, fRF = 820MHz to 920MHz, fLO = 670MHz to 865MHz, fIF = 100MHz, fRF > fLO, TC = -40°C to +85°C. Typical values are at VCC = 5.0V, PRF = -5dBm, PLO = 0dBm, fRF = 870MHz, fLO = 770MHz, fIF = 100MHz, TC = +25°C, unless otherwise noted.) (Note 1) PARAMETER Noise Figure, Single Sideband SYMBOL NF Noise Figure under Blocking Condition Input Compression Point Output Compression Point TYP MAX UNITS fIF = 190MHz, no blockers present (Note 3) 10.5 13 dB +11dBm blocker tone applied to RF port at 961MHz, fRF = 860MHz, fLO = 670MHz, fIFDESIRED = 190MHz, fBLOCKER = 291MHz (Notes 3, 4) 21 26 dB MIN P1dB OP1dB 18.5 PRF = -5dBm, fRF = PBLOCKER = +8dBm 870MHz, fBLOCKER PBLOCKER = +11dBm = 871MHz Small-Signal Compression under Blocking Conditions Third-Order Input Intercept Point CONDITIONS IIP3 PRF = -5dBm/tone, fIF = 100MHz, fRF1-fRF2 = 1MHz (Note 3) 2RF-2LO Spur 2x2 fRF = 870MHz, fLO PRF = -10dBm = 770MHz, fSPUR = PRF = -5dBm 820MHz (Note 3) 3RF-3LO Spur 3x3 LO1-to-LO2 Port Isolation fRF = 870MHz, fLO PRF = -10dBm = 770MHz, fSPUR = 803.3MHz (Note 3) PRF = -5dBm PLO1 = +3dBm, PLO2 = +3dBm, fLO1-fLO2 = 1MHz, PRF = -5dBm, fIF = 100MHz (Notes 3, 5) dBm dB 0.25 28.5 dBm -0.01 dB/°C 32.0 34.5 dBm 63 77 58 72 70 85 60 75 39 43 Third-Order Input Intercept Point Variation over Temperature OIP3 dBm 0.1 fRF1-fRF2 = 1MHz, fIF = 100MHz, PRF = -5dBm/tone Third-Order Output Intercept Point 16.2 21.2 dBc dBc dB Maximum LO Leakage at RF Port -40 -30 dBm Maximum 2LO Leakage at RF Port -45 -20 dBm -30 -20 dBm Maximum LO Leakage at IF Port Minimum RF-to-IF Isolation Minimum Channel-to-Channel Isolation PRF = -10dBm, RFMAIN (RFDIV) power measured at IFDIV (IFMAIN), relative to IFMAIN (IFDIV), all unused ports terminated to 50Ω 30 45 dB 40 47 dB _______________________________________________________________________________________ 3 MAX9985 AC ELECTRICAL CHARACTERISTICS (continued) MAX9985 Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch AC ELECTRICAL CHARACTERISTICS (continued) (Using the Typical Application Circuit, VCC = 4.75V to 5.25V, RF and LO ports are driven from 50Ω sources, PLO = -3dBm to +3dBm, PRF = -5dBm, fRF = 820MHz to 920MHz, fLO = 670MHz to 865MHz, fIF = 100MHz, fRF > fLO, TC = -40°C to +85°C. Typical values are at VCC = 5.0V, PRF = -5dBm, PLO = 0dBm, fRF = 870MHz, fLO = 770MHz, fIF = 100MHz, TC = +25°C, unless otherwise noted.) (Note 1) PARAMETER LO Switching Time SYMBOL CONDITIONS 50% of LOSEL to IF settled within 2 degrees (Note 3) MIN TYP MAX UNITS 0.05 1 µs RF Input Impedance 50 Ω LO Input Impedance 50 Ω IF Output Impedance Differential 200 Ω RF Input Return Loss LO on and IF terminated 24 dB LO port selected 35 LO port unselected 36 RF terminated in 50Ω 20 LO Input Return Loss IF Return Loss dB dB Note 1: All limits reflect losses of external components. Output measurements taken at IF outputs of the Typical Application Circuit. Note 2: Performance is guaranteed for fRF = 820MHz to 920MHz, fLO = 670MHz to 865MHz, and fIF = 100MHz. Operation outside this range is possible, but with degraded performance of some parameters. See the Typical Operating Characteristics. Note 3: Guaranteed by design and characterization. Note 4: Measured with external LO source noise filtered so the noise floor is -174dBm/Hz. This specification reflects the effects of all SNR degradations in the mixer including the LO noise, as defined in Maxim Application Note 2021. Note 5: Measured at IF port at IF frequency. LOSEL may be in any logic state. Note 6: Performance at TC = -40°C is guaranteed by design. 4 _______________________________________________________________________________________ Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch CONVERSION GAIN vs. RF FREQUENCY PLO = -3dBm, 0dBm, +3dBm 5 4 4 800 900 INPUT IP3 vs. RF FREQUENCY INPUT IP3 (dBm) 1000 700 TC = +25°C TC = -30°C 24 900 MAX9985 toc05 28 27 PLO = -3dBm, 0dBm, +3dBm 26 1000 29 10 TC = -30°C 800 900 TC = +25°C 13 11 10 PLO = -3dBm, 0dBm, +3dBm 900 RF FREQUENCY (MHz) 1000 1000 14 13 12 VCC = 5.25V 11 10 VCC = 5.0V 9 VCC = 4.75V 8 7 800 900 NOISE FIGURE vs. RF FREQUENCY 12 9 800 RF FREQUENCY (MHz) 8 7 700 700 1000 MAX9985 toc08 14 NOISE FIGURE (dB) 11 8 26 NOISE FIGURE vs. RF FREQUENCY 12 9 VCC = 5.25V 27 RF FREQUENCY (MHz) MAX9985 toc07 TC = +85°C 28 24 700 NOISE FIGURE vs. RF FREQUENCY 13 VCC = 5.0V VCC = 4.75V 25 RF FREQUENCY (MHz) 14 1000 INPUT IP3 vs. RF FREQUENCY 24 800 900 30 25 700 800 RF FREQUENCY (MHz) NOISE FIGURE (dB) INPUT IP3 (dBm) 28 29 25 NOISE FIGURE (dB) 900 30 MAX9985 toc04 TC = +85°C 26 800 INPUT IP3 vs. RF FREQUENCY 30 27 5 RF FREQUENCY (MHz) RF FREQUENCY (MHz) 29 VCC = 4.75V, 5.0V, 5.25V 4 700 1000 INPUT IP3 (dBm) 700 6 MAX9985 toc06 TC = +25°C 6 7 MAX9985 toc09 TC = +85°C 7 CONVERSION GAIN (dB) 6 CONVERSION GAIN vs. RF FREQUENCY 8 MAX9985 toc02 MAX9985 toc01 7 CONVERSION GAIN (dB) CONVERSION GAIN (dB) TC = -30°C 5 8 MAX9985 toc03 CONVERSION GAIN vs. RF FREQUENCY 8 7 700 800 900 RF FREQUENCY (MHz) 1000 700 800 900 1000 RF FREQUENCY (MHz) _______________________________________________________________________________________ 5 MAX9985 Typical Operating Characteristics (Using the Typical Application Circuit, VCC = 5.0V, PLO = 0dBm, PRF = -5dBm, fRF > fLO, fIF = 100MHz, TC = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (Using the Typical Application Circuit, VCC = 5.0V, PLO = 0dBm, PRF = -5dBm, fRF > fLO, fIF = 100MHz, TC = +25°C, unless otherwise noted.) TC = +25°C 60 55 70 PLO = -3dBm 65 PLO = 0dBm 60 900 1000 700 800 RF FREQUENCY (MHz) 75 TC = -30°C 65 PRF = -5dBm 85 75 PLO = -3dBm, 0dBm, +3dBm 65 900 800 INPUT P1dB vs. RF FREQUENCY TC = +85°C TC = +25°C 17 16 PLO = -3dBm, 0dBm, +3dBm 15 1000 RF FREQUENCY (MHz) 1100 1200 900 MAX9985 toc12 1000 19 18 VCC = 5.25V 17 16 VCC = 5.0V 15 VCC = 4.75V 14 13 13 13 900 800 INPUT P1dB vs. RF FREQUENCY 14 14 800 700 RF FREQUENCY (MHz) 18 INPUT P1dB (dBm) 16 700 VCC = 5.25V 65 INPUT P1dB vs. RF FREQUENCY 17 VCC = 4.75V 75 1000 MAX9985 toc17 18 6 900 19 MAX9985 toc16 19 TC = -30°C VCC = 5.0V 85 RF FREQUENCY (MHz) RF FREQUENCY (MHz) 15 PRF = -5dBm 55 700 1000 INPUT P1dB (dBm) 800 1000 3RF-3LO RESPONSE vs. RF FREQUENCY 55 55 900 95 3RF-3LO RESPONSE (dBc) 3RF-3LO RESPONSE (dBc) 3RF-3LO RESPONSE (dBc) TC = +85°C 700 800 RF FREQUENCY (MHz) 3RF-3LO RESPONSE vs. RF FREQUENCY 95 MAX9985 toc13 PRF = -5dBm TC = +25°C 85 700 1000 RF FREQUENCY (MHz) 3RF-3LO RESPONSE vs. RF FREQUENCY 95 900 MAX9985 toc14 800 60 50 50 700 VCC = 4.75V, 5.0V, 5.25V 65 55 55 50 70 MAX9985 toc15 TC = -30°C PRF = -5dBm 75 2RF-2LO RESPONSE (dBc) 70 65 75 2RF-2LO RESPONSE (dBc) 2RF-2LO RESPONSE (dBc) 75 PRF = -5dBm PLO = +3dBm 80 MAX9985 toc11 PRF = -5dBm MAX9985 toc10 TC = +85°C 2RF-2LO RESPONSE vs. RF FREQUENCY 2RF-2LO RESPONSE vs. RF FREQUENCY 80 MAX9985 toc18 2RF-2LO RESPONSE vs. RF FREQUENCY 80 INPUT P1dB (dBm) MAX9985 Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch 700 800 900 1000 RF FREQUENCY (MHz) 1100 1200 700 800 900 1000 RF FREQUENCY (MHz) _______________________________________________________________________________________ 1100 1200 Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch CHANNEL ISOLATION vs. RF FREQUENCY 45 TC = -30°C, +25°C, +85°C 40 50 45 PLO = -3dBm, 0dBm, +3dBm 40 900 700 1000 800 900 700 1000 800 RF FREQUENCY (MHz) RF FREQUENCY (MHz) LO LEAKAGE AT IF PORT vs. LO FREQUENCY TC = +25°C TC = -30°C -25 -30 TC = +85°C -35 -15 -20 PLO = 0dBm -25 1000 LO LEAKAGE AT IF PORT vs. LO FREQUENCY LO LEAKAGE AT IF PORT vs. LO FREQUENCY MAX9985 toc23 -15 900 RF FREQUENCY (MHz) -10 LO LEAKAGE AT IF PORT (dBm) MAX9985 toc22 -10 -20 VCC = 4.75V, 5.0V, 5.25V 40 PLO = +3dBm -30 -35 -10 MAX9985 toc24 800 LO LEAKAGE AT IF PORT (dBm) 700 45 30 30 30 50 35 35 35 LO LEAKAGE AT IF PORT (dBm) 55 CHANNEL ISOLATION (dB) 55 CHANNEL ISOLATION (dB) 50 CHANNEL ISOLATION vs. RF FREQUENCY 60 MAX9985 toc20 MAX9985 toc19 55 CHANNEL ISOLATION (dB) 60 MAX9985 toc21 CHANNEL ISOLATION vs. RF FREQUENCY 60 -15 -20 VCC = 5.25V -25 VCC = 5.0V -30 VCC = 4.75V -35 PLO = -3dBm 700 750 800 850 900 600 650 700 750 800 850 600 900 650 700 750 800 LO FREQUENCY (MHz) LO FREQUENCY (MHz) LO FREQUENCY (MHz) RF-TO-IF ISOLATION vs. RF FREQUENCY RF-TO-IF ISOLATION vs. RF FREQUENCY RF-TO-IF ISOLATION vs. RF FREQUENCY 55 50 TC = +25°C 45 55 RF-TO-IF ISOLATION (dB) TC = +85°C 40 50 45 40 PLO = -3dBm, 0dBm, +3dBm 850 900 60 MAX9985 toc27 60 MAX9985 toc25 60 55 RF-TO-IF ISOLATION (dB) 650 MAX9985 toc26 600 RF-TO-IF ISOLATION (dB) -40 -40 -40 50 45 40 VCC = 4.75V, 5.0V, 5.25V TC = -30°C 35 35 35 30 30 30 700 800 900 RF FREQUENCY (MHz) 1000 700 800 900 RF FREQUENCY (MHz) 1000 700 800 900 1000 RF FREQUENCY (MHz) _______________________________________________________________________________________ 7 MAX9985 Typical Operating Characteristics (continued) (Using the Typical Application Circuit, VCC = 5.0V, PLO = 0dBm, PRF = -5dBm, fRF > fLO, fIF = 100MHz, TC = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (Using the Typical Application Circuit, VCC = 5.0V, PLO = 0dBm, PRF = -5dBm, fRF > fLO, fIF = 100MHz, TC = +25°C, unless otherwise noted.) -30 TC = -30°C -40 TC = +85°C -50 -60 -30 -40 PLO = -3dBm, 0dBm, +3dBm -50 600 700 800 900 1000 1100 1200 MAX9985 toc30 VCC = 4.75V, 5.0V, 5.25V -50 -60 500 600 700 800 900 1000 1100 1200 500 600 700 800 900 1000 1100 1200 LO FREQUENCY (MHz) 2LO LEAKAGE AT RF PORT vs. LO FREQUENCY 2LO LEAKAGE AT RF PORT vs. LO FREQUENCY 2LO LEAKAGE AT RF PORT vs. LO FREQUENCY TC = +85°C -40 -50 PLO = 0dBm -30 PLO = -3dBm -40 -50 -60 800 900 1000 1100 1200 -40 VCC = 4.75V, 5.0V, 5.25V -50 500 600 700 800 900 500 1000 1100 1200 600 700 800 900 1000 1100 1200 LO FREQUENCY (MHz) LO FREQUENCY (MHz) LO FREQUENCY (MHz) LO SWITCH ISOLATION vs. RF FREQUENCY LO SWITCH ISOLATION vs. RF FREQUENCY LO SWITCH ISOLATION vs. RF FREQUENCY TC = +85°C TC = +25°C 35 30 45 40 PLO = -3dBm, 0dBm, 3dBm 35 900 1000 RF FREQUENCY (MHz) 1100 1200 MAX9985 toc36 45 40 VCC = 4.75V, 5.0V, 5.25V 35 30 30 800 50 LO SWITCH ISOLATION (dB) 40 MAX9985 toc35 TC = -30°C 45 50 LO SWITCH ISOLATION (dB) MAX9985 toc34 50 700 -30 -60 -60 700 -20 PLO = +3dBm TC = -30°C 600 MAX9985 toc33 MAX9985 toc32 -20 -10 2LO LEAKAGE AT RF PORT (dBm) -30 -10 2LO LEAKAGE AT RF PORT (dBm) MAX9985 toc31 TC = +25°C 600 -40 LO FREQUENCY (MHz) -20 500 -30 LO FREQUENCY (MHz) -10 8 -20 -60 500 2LO LEAKAGE AT RF PORT (dBm) MAX9985 toc29 -20 LO LEAKAGE AT RF PORT (dBm) MAX9985 toc28 LO LEAKAGE AT RF PORT (dBm) -20 TC = +25°C LO LEAKAGE AT RF PORT vs. LO FREQUENCY LO LEAKAGE AT RF PORT vs. LO FREQUENCY LO LEAKAGE AT RF PORT (dBm) LO LEAKAGE AT RF PORT vs. LO FREQUENCY LO SWITCH ISOLATION (dB) MAX9985 Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch 600 700 800 900 1000 RF FREQUENCY (MHz) 1100 1200 600 700 800 900 1000 RF FREQUENCY (MHz) _______________________________________________________________________________________ 1100 1200 Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch 10 PLO = -3dBm, 0dBm, +3dBm 20 25 20 30 600 700 800 900 1000 1100 1200 PLO = +3dBm 20 PLO = 0dBm 30 40 100 200 300 400 500 500 1000 1100 1200 CONVERSION GAIN vs. RF FREQUENCY (VARIOUS LO AND IF BUFFER BIAS) SUPPLY CURRENT (mA) VCC = 5.25V 410 VCC = 5.0V 400 VCC = 4.75V 390 380 1 6.5 360 600 700 800 900 5.5 -35 1000 1100 1200 -15 5 25 45 65 4 2 3 6.0 370 50 0 6 5 MAX9985 toc42 420 7.0 CONVERSION GAIN (dB) MAX9985 toc40 430 40 7 8, 9 SEE TABLE 1 FOR R1, R2, AND ICC VALUES. 700 85 800 900 1000 TEMPERATURE (°C) RF FREQUENCY (MHz) INPUT IP3 vs. RF FREQUENCY (VARIOUS LO AND IF BUFFER BIAS) 2RF-2LO RESPONSE vs. RF FREQUENCY (VARIOUS LO AND IF BUFFER BIAS) 3RF-3LO RESPONSE vs. RF FREQUENCY (VARIOUS LO AND IF BUFFER BIAS) 26 25 5 3 23 22 9 8 70 5 8 RF FREQUENCY (MHz) 60 1000 6 0 75 7 900 3 2 65 SEE TABLE 1 FOR R1, R2, AND ICC VALUES. 800 80 800 3 PRF = -5dBm 85 6 1 2 0 80 75 70 5 4 65 9 8 7 60 7 SEE TABLE 1 FOR R1, R2, AND ICC VALUES. 700 90 3RF-3LO RESPONSE (dBc) 27 6 PRF = -5dBm MAX9985 toc44 4 28 85 2RF-2LO RESPONSE (dBc) 2 MAX9985 toc43 1 0 MAX9985 toc45 LO FREQUENCY (MHz) 30 700 900 SUPPLY CURRENT vs. TEMPERATURE (TC) 30 20 800 LO UNSELECTED RETURN LOSS vs. LO FREQUENCY PLO = -3dBm, 0dBm, +3dBm 21 700 LO FREQUENCY (MHz) 20 24 600 IF FREQUENCY (MHz) 10 29 PLO = -3dBm RF FREQUENCY (MHz) 0 500 MAX9985 toc39 10 50 0 MAX9985 toc41 500 LO UNSELECTED RETURN LOSS (dB) 15 25 30 INPUT IP3 (dBm) VCC = 4.75V, 5.0V, 5.25V 10 0 LO SELECTED RETURN LOSS (dB) 5 IF PORT RETURN LOSS (dB) 5 MAX9985 toc38 0 MAX9985 toc37 RF PORT RETURN LOSS (dB) 0 15 LO SELECTED RETURN LOSS vs. LO FREQUENCY IF PORT RETURN LOSS vs. IF FREQUENCY RF PORT RETURN LOSS vs. RF FREQUENCY 900 RF FREQUENCY (MHz) 55 1000 SEE TABLE 1 FOR R1, R2, AND ICC VALUES. 700 800 900 1000 RF FREQUENCY (MHz) _______________________________________________________________________________________ 9 MAX9985 Typical Operating Characteristics (continued) (Using the Typical Application Circuit, VCC = 5.0V, PLO = 0dBm, PRF = -5dBm, fRF > fLO, fIF = 100MHz, TC = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) 15 1, 2, 3 14 13 4, 5, 6 12 11 10 9 8 0Ω -20 L = 7.5nH -25 -30 L = 30nH L = 15nH 800 900 RF FREQUENCY (MHz) 1000 L = 30nH 50 40 L = 7.5nH 0Ω SEE TABLE 1 FOR R1, R2, AND ICC VALUES. 700 60 30 L = 15nH -35 7, 8, 9 MAX9985 toc48 -15 70 RF-TO-IF ISOLATION (dB) 16 -10 MAX9985 toc47 0 17 LO LEAKAGE AT IF PORT (dBm) 18 MAX9985 toc46 (Using the Typical Application Circuit, VCC = 5.0V, PLO = 0dBm, PRF = -5dBm, fRF > fLO, fIF = 100MHz, TC = +25°C, unless otherwise noted.) INPUT P1dB vs. RF FREQUENCY RF-TO-IF ISOLATION vs. RF FREQUENCY LO LEAKAGE AT IF PORT vs. LO FREQUENCY (VARIOUS LO AND IF BUFFER BIAS) (VARIOUS VALUES OF L3 AND L6) (VARIOUS VALUES OF L3 AND L6) INPUT P1dB (dBm) MAX9985 Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch 20 -40 600 650 700 750 800 850 700 900 800 1000 900 RF FREQUENCY (MHz) LO FREQUENCY (MHz) Table 1. DC Current vs. Bias Resistor Settings 10 BIAS CONDITION DC CURRENT (mA) R1 AND R4 VALUES (Ω) R2 AND R5 VALUES (Ω) 0 397.8 1070 1100 1 345.0 1400 1100 2 316.5 1400 1620 3 297.5 1400 2210 4 301.2 1910 1100 5 271.7 1910 1620 6 252.2 1910 2210 7 260.1 2800 1100 8 230.5 2800 1620 9 211.5 2800 2210 ______________________________________________________________________________________ Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch PIN NAME 1 RFMAIN FUNCTION 2 TAPMAIN 3, 5, 7, 12, 20, 22, 24, 25, 26, 34 GND Ground 4, 6, 10, 16, 21, 30, 36 VCC Power Supply. Connect bypass capacitors as close to the pin as possible (see the Typical Application Circuit). 8 TAPDIV 9 RFDIV 11 IFDBIAS 13, 14 IFD+, IFD- Diversity Mixer Differential IF Output. Connect pullup inductors from each of these pins to VCC (see the Typical Application Circuit). 15 LEXTD Connect a 30nH inductor from this pin to ground to increase the RF-to-IF and LO-to-IF isolation. Connect this pin to ground if isolations can be degraded (see the Typical Operating Characteristics for typical degradation). 17 LODBIAS LO Diversity Amplifier Bias Control. Connect a 1.1kΩ resistor from this pin to ground to set the bias current for the diversity LO amplifier (see the Typical Operating Characteristics for typical performance versus resistor value). 18, 28 N.C. No Connection. Not internally connected. 19 LO1 Local Oscillator 1 Input. This input is internally matched to 50Ω. Requires an input DC-blocking capacitor. 23 LOSEL 27 LO2 29 LOMBIAS 31 LEXTM 32, 33 IFM-, IFM+ Main Mixer Differential IF Output. Connect pullup inductors from each of these pins to VCC (see the Typical Application Circuit). 35 IFMBIAS IF Main Amplifier Bias Control. Connect a 1.07kΩ resistor from this pin to ground to set the bias current for the main IF amplifier (see the Typical Operating Characteristics for typical performance vs. resistor value). — EP Exposed Paddle. Solder the exposed paddle to the ground plane using multiple vias. This paddle affects RF performance and provides heat dissipation. Main Channel RF input. Internally matched to 50Ω. Requires an input DC-blocking capacitor. Main Channel Balun Center Tap. Bypass to GND with capacitors close to the pin. Diversity Channel Balun Center Tap. Bypass to GND with capacitors close to the pin. Diversity Channel RF Input. Internally matched to 50Ω. Requires an input DC-blocking capacitor. IF Diversity Amplifier Bias Control. Connect a 1.07kΩ resistor from this pin to ground to set the bias current for the diversity IF amplifier (see the Typical Operating Characteristics for typical performance versus resistor value). Local Oscillator Select. Set this pin to high to select LO1. Set low to select LO2. Local Oscillator 2 Input. This input is internally matched to 50Ω. Requires an input DC-blocking capacitor. LO Main Amplifier Bias Control. Connect a 1.1kΩ resistor from this pin to ground to set the bias current for the main LO amplifier (see the Typical Operating Characteristics for typical performance versus resistor value). Connect a 30nH inductor from this pin to ground to increase the RF-IF and LO-IF isolation. Connect this pin to ground if isolations can be degraded (see the Typical Operating Characteristics for typical degradation). ______________________________________________________________________________________ 11 MAX9985 Pin Description MAX9985 Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch Detailed Description The MAX9985 is a dual-channel downconverter designed to provide 6dB of conversion gain, +28.5dBm input IP3, and +16.2dBm 1dB input compression point, with a 10.5dB NF. In addition to its high-linearity performance, the MAX9985 achieves a high level of component integration. The device integrates two double-balanced active mixers for two-channel downconversion. Both the main and diversity channels include a balun and matching circuitry to allow 50Ω single-ended interfaces to the RF ports and the two LO ports. An integrated single-pole, double-throw (SPDT) switch provides 50ns switching time between the two LO inputs with 43dB of LO-to-LO isolation and a -40dBm of LO leakage at the RF port. Furthermore, the integrated LO buffers provide a high drive level to each mixer core, reducing the LO drive required at the MAX9985’s inputs to a -3dBm to +3dBm range. The IF ports for both channels incorporate differential outputs for downconversion, which is ideal for providing enhanced IIP2 performance. Dual-channel downconversion makes the MAX9985 ideal for diversity receiver applications. In addition, specifications are guaranteed over broad frequency ranges to allow for use in GSM 850/950, 2G/2.5G EDGE, WCDMA, cdma2000, and iDEN base stations. The MAX9985 is specified to operate over a 700MHz to 1000MHz RF input range, a 570MHz to 865MHz LO range, and a 50MHz to 250MHz IF range. The external IF components set the lower frequency range (see the Typical Operating Characteristics for details). RF Port and Balun The RF input ports to both the main and diversity channels are internally matched to 50Ω, requiring no external matching components. A DC-blocking capacitor is required as the input is internally DC-shorted to ground through the on-chip balun. The RF port return loss is typically 15dB over the entire 700MHz to 1000MHz RF frequency range. LO Inputs, Buffer, and Balun The MAX9985 is optimized for a 570MHz to 865MHz LO frequency range. As an added feature, the MAX9985 includes an internal LO SPDT switch for use in frequency-hopping applications. The switch selects one of the two single-ended LO ports, allowing the external oscillator to settle on a particular frequency before it is switched in. LO switching time is typically less than 50ns, which is more than adequate for typical GSM applications. If frequency hopping is not employed, simply set the switch to either of the LO inputs. The switch is controlled by a digital input 12 (LOSEL), where logic-high selects LO1 and logic-low selects LO2. LO1 and LO2 inputs are internally matched to 50Ω, requiring only an 82pF DC-blocking capacitor. To avoid damage to the part, voltage MUST be applied to VCC before digital logic is applied to LOSEL. Alternatively, a 1kΩ resistor can be placed in series at the LOSEL to limit the input current in applications where LOSEL is applied before VCC. The main and diversity channels incorporate a twostage LO buffer that allows for a wide-input power range for the LO drive. All guaranteed specifications are for an LO signal power from -3dBm to +3dBm. The on-chip low-loss baluns, along with LO buffers, drive the double-balanced mixers. All interfacing and matching components from the LO inputs to the IF outputs are integrated on-chip. High-Linearity Mixer The core of the MAX9985 dual-channel downconverter consists of two double-balanced, high-performance passive mixers. Exceptional linearity is provided by the large LO swing from the on-chip LO buffers. When combined with the integrated IF amplifiers, the cascaded IIP3, 2RF-2LO rejection, and NF performance are typically +28.5dBm, 77dBc, and 10.5dB, respectively. Differential IF The MAX9985 has a 50MHz to 250MHz IF frequency range, where the low-end frequency depends on the frequency response of the external IF components. Note that these differential ports are ideal for providing enhanced IIP2 performance. Single-ended IF applications require a 4:1 (impedance ratio) balun to transform the 200Ω differential IF impedance to a 50Ω singleended system. After the balun, the IF return loss is better than 20dB. The user can use a differential IF amplifier on the mixer IF ports, but a DC block is required on both IFD+/IFD- and IFM+/IFM- ports to keep external DC from entering the IF ports of the mixer. Applications Information Input and Output Matching The RF and LO inputs are internally matched to 50Ω. No matching components are required. Return loss at the RF port is typically 15dB over the entire input range and return loss at the LO ports are typically 25dB. RF and LO inputs require only DC-blocking capacitors for interfacing. The IF output impedance is 200Ω (differential). For evaluation, an external low-loss 4:1 (impedance ratio) balun transforms this impedance to a 50Ω single-ended output (see the Typical Application Circuit). ______________________________________________________________________________________ Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch Power-Supply Bypassing Proper voltage-supply bypassing is essential for highfrequency circuit stability. Bypass each VCC pin and TAPMAIN/TAPDIV with the capacitors shown in the Typical Application Circuit (see Table 2 for component values). Place the TAPMAIN/TAPDIV bypass capacitor to ground within 100 mils of the pin. IF Amplifier Bias Resistors Bias currents for the two on-chip IF amplifiers are optimized by fine-tuning the off-chip resistors on IFDBIAS (pin 11) and IFMBIAS (pin 35). The current in the IF amplifiers is decreased by raising the value of these resistors, but performance may degrade. See the Typical Operating Characteristics for key performance parameters versus this resistor value. Doubling the value of this resistor reduces the current in each IF amplifier from 100mA to approximately 50mA (see Table 1). Table 2. Component Values COMPONENT VALUE C1, C2, C7, C8 39pF C3, C6 0.033µF C4, C5 — C9, C13, C15, C17, C18 0.01µF Microwave capacitors (0402) C10, C11, C12, C19, C20, C21 150pF Microwave capacitors (0603) C14, C16 82pF Microwave capacitors (0402) L1, L2, L4, L5 560nH Wire-wound high-Q inductors (0805) L3, L6 30nH Wire-wound high-Q inductors (0603) R1, R4 1.07kΩ R2, R5 1.1kΩ R3, R6 0Ω Resistors (1206) T1, T2 4:1 Transformers (200:50) Mini-Circuits TC4-1W-7A U1 — MAX9985 IC LEXT Inductor Short LEXT_ to ground using a 0Ω resistor. For applications requiring improved RF-to-IF and LO-to-IF isolation, LEXT_ can be used by connecting a low-ESR inductor from LEXT_ to GND. See the Typical Operating Characteristics on RF-to-IF port isolation and LO-to-IF port leakage for various inductor values. The load impedance presented to the mixer must be such that any capacitance from both IF- and IF+ to ground do not exceed several picofarads to ensure stable operating conditions. Approximately 100mA flows through LEXT_, so it is important to use a low-DCR wire-wound inductor. Layout Considerations A properly designed PCB is an essential part of any RF/microwave circuit. Keep RF signal lines as short as possible to reduce losses, radiation, and inductance. For the best performance, route the ground pin traces directly to the exposed paddle under the package. The PCB exposed paddle MUST be connected to the ground plane of the PCB. It is suggested that multiple vias be used to connect this paddle to the lower-level ground planes. This method provides a good RF/thermal-conduction path for the device. Solder the exposed paddle on the bottom of the device package to the PCB. Refer to the MAX9985 Evaluation Kit as a reference for board layout. Gerber files are available upon request at www.maxim-ic.com. DESCRIPTION Microwave capacitors (0402) Microwave capacitors (0603) Not used ±1% resistors (0402) ±1% resistors (0402) Exposed Paddle RF/Thermal Considerations The exposed paddle (EP) of the MAX9985’s 36-pin thin QFN-EP package provides a low thermal-resistance path to the die. It is important that the PCB on which the MAX9985 is mounted be designed to conduct heat from the EP. In addition, provide the EP with a lowinductance path to electrical ground. The EP MUST be soldered to a ground plane on the PCB, either directly or through an array of plated via holes. ______________________________________________________________________________________ 13 MAX9985 LO Buffer Bias Resistors Bias currents for the two on-chip LO buffers is optimized by fine-tuning the off-chip resistors on LODBIAS (pin 17) and LOMBIAS (pin 29). The current in the buffer amplifiers is reduced by increasing the value of these resistors, but performance may degrade. See the Typical Operating Characteristics for key performance parameters versus this resistor value. Doubling the value of these resistors reduces the total chip current by approximately 50mA (see Table 1). Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch MAX9985 Typical Application Circuit C19 VCC IF MAIN OUTPUT T1 L1 C21 R3 L2 4:1 C20 VCC VCC C1 TAPMAIN C3 C2 GND VCC VCC C4 GND VCC VCC C5 C6 GND C7 TAPDIV RFDIV RF DIV INPUT 35 34 33 32 LOMBIAS VCC LEXTM IFM- IFM+ GND IFMBIAS VCC 36 RFMAIN RF MAIN INPUT C17 L3 31 30 29 R2 N.C. R1 C18 28 27 1 26 2 MAX9985 3 25 4 24 5 23 6 22 7 21 EXPOSED PADDLE 8 20 19 9 C8 LO2 GND LO2 C16 GND GND LOSEL LO SELECT GND VCC VCC C15 GND LO1 LO1 C14 17 VCC VCC 18 N.C. 16 LODBIAS 15 LEXTD 14 IFD- 13 IFD+ 12 GND 11 IFDBIAS VCC 10 R5 VCC L6 R4 C13 C9 C11 VCC T2 L5 C12 R6 L4 4:1 C10 14 IF DIV OUTPUT ______________________________________________________________________________________ Dual, SiGe, High-Linearity, 700MHz to 1000MHz Downconversion Mixer with LO Buffer/Switch RFMAIN 1 TAPMAIN 2 VCC IFMBIAS GND IFM+ IFM- LEXTM VCC LOMBIAS N.C. TOP VIEW (with exposed paddle on the bottom of the package) 36 35 34 33 32 31 30 29 28 27 LO2 26 GND MAX9985 GND 3 25 GND VCC 4 24 GND GND 5 23 LOSEL VCC 6 22 GND GND 7 21 VCC 20 GND 19 LO1 13 14 15 16 17 18 VCC LODBIAS N.C. 12 LEXTD 11 IFD- 10 IFD+ 9 GND RFDIV IFDBIAS 8 VCC TAPDIV EXPOSED PADDLE THIN QFN 6mm x 6mm Chip Information PROCESS: SiGe BiCMOS Package Information For the latest package outline information, go to www.maxim-ic.com/packages. 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 ____________________ 15 © 2007 Maxim Integrated Products CARDENAS is a registered trademark of Maxim Integrated Products, Inc. MAX9985 Pin Configuration/Functional Diagram