MAXIM MAX9985 handbook
Contents
1. 700 800 900 1000 700 800 900 1000 700 800 900 1000 RF FREQUENCY MHz RF FREQUENCY MHz RF FREQUENCY MHz INPUT IP3 vs RF FREQUENCY INPUT IP3 vs RF FREQUENCY INPUT IP3 vs RF FREQUENCY E 5 ca co gt 2 amp g 5 5 3dBm 0dBm 3dBm 5 n a a 4 ae ome 700 800 900 1000 700 800 900 1000 700 800 900 1000 RF FREQUENCY MHz RF FREQUENCY MHz RF FREQUENCY MHz NOISE FIGURE vs RF FREQUENCY NOISE FIGURE vs RF FREQUENCY NOISE FIGURE vs RF FREQUENCY 5 4 8 11 860 E 3 2 a Voc 5 25V gt gt 5 11 om Lu LL 0 D B D 2 5 3dBm 04 3dBm Tc 425 C 8 7 700 800 900 1000 700 800 900 1000 700 800 900 1000 RF FREQUENCY MHz RF FREQUENCY MHz RF FREQUENCY MHz 5 S866XVIN MAX9985 Dual SiGe High Linearity 7OOMHz to 1000MHz Downconversion Mixer with LO Buffer Switch Typical Operating Characteristics continued Using the Typical Application Circuit Vcc 5 0V PLO OdBm Pnr 5dBm fnr gt fir 100MHz 25 C unless other wise noted 2RF 2LO RESPONSE2. CHANNEL ISOLATION vs RF FREQUENCY CHANNEL ISOLATION vs RF FREQUENCY CHANNEL ISOLATION vs RF FREQUENCY Z 3 3 zy a a REA RA 5 2 2 2 u Tc 30 C 25 C 85 C zi 3dBm 04 3dBm Er Voc 4 75V 5 0V 5 a a rA Le c c c 700 800 900 1000 700 800 900 1000 700 800 900 1000 RF FREQUENCY MHz RF FREQUENCY MHz RF FREQUENCY MHz LO LEAKAGE AT IF PORT vs LO FREQUENCY LO LEAKAGE AT IF PORT vs LO FREQUENCY LO LEAKAGE AT IF PORT vs LO FREQUENCY 10 g 8 10 5 m io _ 15 3 i S 8 8 20 E 20 e e Vec 5 25V 25 amp 225 Vec 5 0V g 30 2 30 8j E E Vec 4 75V 35 35 40 40 600 650 700 750 800 850 900 600 650 700 750 800 850 900 600 650 700 750 800 850 900 LO FREQUENCY MHz LO FREQUENCY MHz LO FREQUENCY MHz 0 ISOLATION 0 ISOLATION 0 ISOLATION vs RF FREQUENCY vs RF FREQUENCY vs RF FREQUENCY a a a mx lt E E Lon T e e e 3dBm 0dBm 3dBm 700 800 900 1000 700 800 900 1000 700 800 900 1000 RF FREQUENCY MHz RF FREQUENCY MHz RF FREQUENCY MHz S866XVIN MAX9985 Dual SiGe High Linearity 7OOMHz to 1000MHz Downconversion Mixer with LO Buffer Switch Typical Operating Characteristics continued Using the Typical Application Circuit Vcc
3. package Denotes lead free and RoHS compliant Maxim Integrated Products 1 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 S866XVIN MAX9985 Dual SiGe High Linearity 7OOMHz to 1000MHz Downconversion Mixer with LO Buffer Switch ABSOLUTE MAXIMUM RATINGS VECO GND xeu ae oerte 0 3V to 5 5V Maximum Junction Temperature 150 C 0 3V 38 C W Any Other Pins to 0 3V to Vcc 0 3V Oi Cereal scu Me ea nace meen ties 7 49 RFMAIN RFDIV and LO Input 20dBm Storage Temperature Range 65 C to 150 C RFMAIN RFDIV Current RF is DC shorted to GND through Lead Temperature soldering 105 300 C Dall E 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 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
4. a 2 2 2 2 40 2 40 SE am 24 T 3dBm 0dBm 3dBm g wn wn wn S 35 S 55 30 30 600 700 800 900 1000 1100 1200 600 700 800 900 1000 1100 1200 600 700 800 900 1000 1100 1200 RF FREQUENCY MHz RF FREQUENCY MHz RF FREQUENCY MHz 8 MAXIM Dual SiGe High Linearity 7OOMHz to 1000MHz Downconversion Mixer with LO Buffer Switch Typical Operating Characteristics continued Using the Typical Application Circuit Vcc 5 0V PLO OdBm Pnr 5dBm fnr gt fir 100 2 25 C unless other wise noted RF PORT RETURN LOSS IF PORT RETURN LOSS LO SELECTED RETURN LOSS vs RF FREQUENCY vs IF FREQUENCY vs LO FREQUENCY 0 8 0 8 8 5 3 5 2 g 3 g A 8 10 B 10 Hcc 4 75 5 0V 5 25V 5 3dBm OdBm 3dBm E E a fe i Es 20 20 ui c C 25 25 30 30 500 600 700 800 900 1000 1100 1200 0 100 200 300 40 50 500 600 700 800 900 1000 1100 1200 RF FREQUENCY MHz IF FREQUENCY MHz LO FREQUENCY MHz LO UNSELECTED RETURN LOSS SUPPLY CURRENT CONVERSION GAIN vs RF FREQUENCY vs LO FREQUENCY vs TEMPERATURE Tc VARIOUS LO AND IF BUFFER BIAS E E eo 8 z 5 Pio 3
5. F 2LO Spur 870MHz flo PrF 10dBm 770MHz fspuR 820MHz Note 3 5dBm 3RF 3LO Spur LO1 to LO2 Port Isolation fRr 870MHz 10dBm T70MHz fsPUR 803 3MHz Note 3 5dBm PLO4 3dBm PLo2 3dBm fLo1 flo2 1MHz 5dBm fip 100MHz Notes 3 5 Maximum LO Leakage at RF Port Maximum 2LO Leakage at RF Port Maximum LO Leakage at IF Port Minimum RF to IF Isolation Minimum Channel to Channel Isolation Pre 10dBm RFMAIN RFDIV power measured at IFDIV IFMAIN relative to IFMAIN IFDIV all unused ports terminated to 500 S866XVIN MAX9985 Dual SiGe High Linearity 7OOMHz 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 500 sources PLo 3dBm to 3dBm 5dBm fnr 820MHz to 920 2 1 o 670MHz to 865MHZz fip 100 2 fnr gt Tc 40 C to 85 C Typical values are at Voc 5 0V PRF 5dBm Pio OdBm fnr 870 2 fi o 770MHZz fip 100 2 25 C unless otherwise noted Note 1 PARAMETER SYMBOL CONDITIONS 50 of LOSEL to IF settled within 2 degrees Note 3 LO Switching Time RF Input Impedance LO Input Impedance RF Input Return Loss LO on and IF terminated LO port selected LO Inp
6. m 6 z B 1 2 3 20 L 30nH 7 5nH E 5 LL pa 25 4 5 6 TEP E e L 7 5nH amp 3 7 m oen E 1 30nH 5 E L 15nH 7 8 9 35 02 SEE TABLE 1 FOR R1 R2 AND Icc VALUES 40 2 800 900 1000 600 650 700 750 800 850 900 700 800 900 1000 RF FREQUENCY MHz LO FREQUENCY MHz RF FREQUENCY MHz Table 1 DC Current vs Bias Resistor Settings BIAS DC CURRENT CONDITION mA R1 2 5 VALUES VALUES 4 5 6 8 9 Dual SiGe High Linearity 7OOMHz to 1000MHz Downconversion Mixer with LO Buffer Switch Pin Description NAME FUNCTION RFMAIN Main Channel RF input Internally matched to 500 Requires an input DC blocking capacitor TAPMAIN Main Channel Balun Center Tap Bypass to GND with capacitors close to the pin 3 5 7 12 20 22 24 Ground 25 26 34 4 6 10 16 21 30 36 8 TAPDIV Diversity Channel Balun Center Tap Bypass to GND with capacitors close to the pin Power Supply Connect bypass capacitors as close to the pin as possible see the Typical Application Circuit 9 RFDIV Diversity Channel RF Input Internally matched to 50Q Requires an input DC blocking capacitor F Diversity Amplifier Bias Control Connect a 1 07kQ resistor from this pin to ground to set the bias IFDBIAS current for the diversity IF amplifier see the Typical Operating Characteristics for typical performance
7. 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 SYMBOL CONDITIONS Supply Voltage Vcc Total supply current see Table 1 for lower current settings Vcc pin 16 Vcc pin 30 IFM IFM total of both IFD IFD total of both EL Input High Voltage Supply Current EL Input Low Voltage AC ELECTRICAL CHARACTERISTICS Using the Typical Application Circuit Vcc 4 75V to 5 25V RF and LO ports are driven from 500 sources PLo 3dBm to 3dBm 5dBm fnr 820MHz to 920 2 1 o 670MHz to 865MHZz fip 100MHz fnr gt Tc 40 C to 85 C Typical values are at Voc 5 0V PRF 5dBm Pio OdBm far 870 2 fi o 770MHZz fip 100 2 25 C unless otherwise noted Note 1 PARAMETER SYMBOL CONDITIONS RF Frequency fRF Note 2 LO Frequency fLo Note 2 IF matching components affect the IF frequency range Note 2 LO Drive Note 3 IF Frequency Conversion Gain Note 6 Gain Variation over Temperature Flatnes
8. 5 0V PLO OdBm Pnr 5dBm fnr gt fi o fir 100MHz 25 C unless other wise noted LO LEAKAGE AT RF PORT LO LEAKAGE AT RF PORT LO LEAKAGE AT RF PORT vs LO FREQUENCY vs LO FREQUENCY vs LO FREQUENCY 8 20 8 20 8 A 3 3 S 30 S 30 fe T z amp LL Lu LL lt E 4 Lu lt lt g 52 3 50 3dBm OdBm 3dBm _ 5 60 60 500 600 700 800 900 1000 1100 1200 500 600 700 800 900 1000 1100 1200 500 600 700 800 900 1000 1100 1200 LO FREQUENCY MHz LO FREQUENCY MHz LO FREQUENCY MHz 210 LEAKAGE RF PORT 210 LEAKAGE RF PORT 210 LEAKAGE AT RF PORT vs LO FREQUENCY vs LO FREQUENCY vs LO FREQUENCY 5 10 8 10 3 8 8 20 6 20 cc uc 30 uw 30 ec a c9 5 e 5 5 40 5 40 a5 5 5 kam d S e e 50 50 60 60 500 600 700 800 900 1000 1100 1200 500 600 700 800 900 1000 1100 1200 500 600 700 800 900 1000 1100 1200 LO FREQUENCY MHz LO FREQUENCY MHz LO FREQUENCY MHz LO SWITCH ISOLATION LO SWITCH ISOLATION LO SWITCH ISOLATION vs RF FREQUENCY vs RF FREQUENCY vs RF FREQUENCY 50 5 g 50 g A 2 3 8 5 8 45 z
9. degradation Main Mixer Differential IF Output Connect pullup inductors from each of these pins to Vcc see the aus Typical Application Circuit IF Main Amplifier Bias Control Connect a 1 07kQ resistor from this pin to ground to set the bias current for IFMBIA the main IF amplifier see the Typical Operating Characteristics for typical performance vs resistor value Exposed Paddle Solder the exposed paddle to the ground plane using multiple vias This paddle EP affects RF performance and provides heat dissipation 11 S866XVIN MAX9985 Dual SiGe High Linearity 7OOMHz 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 integra tion 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 500 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 hig
10. versus resistor value Diversity Mixer Differential IF Output Connect pullup inductors from each of these pins to Vcc see IFD IFD the Typical Application Cirouib 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 or typical degradation LO Diversity Amplifier Bias Control Connect a 1 1kQ resistor from this pin to ground to set the bias LODBIAS current for the diversity LO amplifier see the Typical Operating Characteristics for typical performance versus resistor value N C No Connection Not internally connected LO1 Local Oscillator 1 Input This input is internally matched to 500 Requires an input DC blocking capacitor Local Oscillator Select Set this pin to high to select LO1 Set low to select LO2 LO2 Local Oscillator 2 Input This input is internally matched to 500 Requires an input DC blocking capacitor LO Main Amplifier Bias Control Connect a 1 1kQ resistor from this pin to ground to set the bias LOMBIAS 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
11. vs RF FREQUENCY 2RF 2L0 RESPONSE vs RF FREQUENCY 2RF 2L0 RESPONSE vs RF FREQUENCY Tc 85 C PRF 5dBm E 3dBm PrF 50 8 Par 5dBm 3 E lu Lu 5 2 Z 22 Pio 0dBm 8 hc S gS 9 B N N N 700 800 900 1000 700 800 900 1000 700 800 900 1000 RF FREQUENCY MHz RF FREQUENCY MHz RF FREQUENCY MHz 3RF 3L0 RESPONSE vs RF FREQUENCY 3RF 3L0 RESPONSE vs RF FREQUENCY E Par 5dBm gt PrF 5dBm E S 5 5 5 5 LL LL 12 4 cc E Pio 3dBm OdBm 3dBm uw uw fix m 700 800 900 1000 700 800 900 1000 700 800 900 1000 RF FREQUENCY MHz RF FREQUENCY MHz RF FREQUENCY MHz INPUT Pap vs RF FREQUENCY INPUT Pap vs RF FREQUENCY INPUT vs RF FREQUENCY E E 3dBm 0dBm 3dB E Lo 3dBm m 3dBm E z z 700 800 900 1000 1100 1200 700 800 900 1000 1100 1200 700 800 90 1000 1100 1200 RF FREQUENCY MHz RF FREQUENCY MHz RF FREQUENCY MHz 6 MAXIM Dual SiGe High Linearity 7OOMHz to 1000MHz Downconversion Mixer with LO Buffer Switch Typical Operating Characteristics continued Using the Typical Application Circuit Vcc 5 0V PLO OdBm Pnr 5dBm fnr gt fi o fir 100 2 25 C unless other wise noted
12. 02 1 resistors 0402 Resistors 1206 Transformers 200 50 Mini Circuits TC4 1W 7A 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 low inductance 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 S866XVIN MAX9985 Dual SiGe High Linearity 7OOMHz to 1000MHz Downconversion Mixer with LO Buffer Switch Typical Application Circuit IF MAIN OUTPUT RF MAIN REMAIN J INPUT gt Ct MAXIM MAX9985 TAPDIV EXPOSED PADDLE RFDIV IF DIV OUTPUT 14 MAXIM Dual SiGe High Linearity 7OOMHz to 1000MHz Downconversion Mixer with LO Buffer Switch Pin Configuration Functional Diagram TOP VIEW with exposed paddle on the bottom of the LOMBIAS TN i REMAIN 1 TAPMAIN 2 MAXIM MAX9985 GND 3 Voc Voc 6 GND 7 EXPOSED TAPDIV 8 PADDLE RFDIV 9 IFDBIAS THIN QFN 6mm x 6mm Chip Information PROCESS SiGe BICMOS Package Information For the latest package outline inf
13. 19 0705 Rev 0 1 07 MAKII Dual SiGe High Linearity 7OOMHz to 1000MHz Downconversion Mixer with LO Buffer Switch General Description The MAX9985 high linearity dual channel downconver sion 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 7OOMHz to 1000MHz RF frequency range and a 570MHz to 865MHz LO frequency range this mixer is ideal for low side 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 inte grates 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 single ended RF and single ended LO inputs The MAX9985 requires a typical OdBm LO drive Supply current is adjustable up to 400mA The MAX9985 is available in a 36 pin thin QFN pack age 6mm x 6mm with an exposed paddle Electrical performance is guaranteed over the extended tempera ture range from Tc 40 C to 85 C Applications 850MHz WCDMA Base Stations GSM 850 GSM 950 2G 2 5G EDGE Base Stations cdmaOne and cdma2000 Base Stations iDEN Base Stations Fixed Broadband
14. 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 ther mal 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 refer ence for board layout Gerber files are available upon request at www maxim ic com Power Supply Bypassing Proper voltage supply bypassing is essential for high frequency 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 Table 2 Component Values COMPONENT C1 C2 C7 C8 C3 C6 C4 C5 C9 C13 C15 C17 C18 C10 C11 C12 C19 C20 C21 C14 C16 DESCRIPTION icrowave capacitors 0402 icrowave capacitors 0603 39pF 0 033uF ot used icrowave capacitors 0402 icrowave capacitors 0603 icrowave capacitors 0402 L1 L2 L4 L5 re wound high Q inductors 196 resistors 04
15. Wireless Access 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 MAKIM 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 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 9 9 9 9 9 9 9 Ordering Information PART TEMP RANGE PIN PACKAGE 36 Thin QFN EP 6mm x 6mm 36 Thin QFN EP 6mm x 6mm MAX9985ET 40 C to 85 C MAX9985ET 40 C to 85 C T R 36 Thin QFN EP 6mm x 6mm lead free bulk MAX9985ETX 40 to 85 C 36 Thin QFN EP 6mm x 6mm lead free T R MAX9985ETX T 40 C to 85 C Exposed paddle T
16. dBm OdBm 3dBm s a Da EN E g 2 8 5 o 4 50 500 600 700 800 900 1000 1100 1200 85 700 800 900 1000 LO FREQUENCY TEMPERATURE C RF FREQUENCY INPUT IP3 vs RF FREQUENCY 2RF 2LO RESPONSE vs RF FREQUENCY 3RF 3L0 RESPONSE vs RF FREQUENCY VARIOUS LO AND IF BUFFER BIAS VARIOUS LO AND IF BUFFER BIAS VARIOUS LO AND IF BUFFER BIAS 30 85 z 90 29 E Pgr 5dBm 2 5dBm 5 E Z 85 5 28 _ 80 2 3 ES E _ 27 2 f S 8 D 0 a S 26 1 5 amp 2 A E ac ac 2 M 9 n sm 23 E i E 5 S 65 22 65 2 8 7 60 SEE TABLE 1 FOR R1 R2 AND Irc VALUES 20 6 55 700 800 900 1000 700 800 900 1000 700 800 900 1000 RF FREQUENCY MHz RF FREQUENCY MHz RF FREQUENCY MHz 9 S866XVIN MAX9985 INPUT dBm Dual SiGe High Linearity 7OOMHz to 1000MHz Downconversion Mixer with LO Buffer Switch 10 INPUT vs RF FREQUENCY VARIOUS LO AND IF BUFFER BIAS Typical Operating Characteristics continued Using the Typical Application Circuit Vcc 5 0V PLO OdBm Pnr 5dBm fnr gt fLo fir 100 2 25 C unless other wise noted LO LEAKAGE AT IF PORT vs LO FREQUENCY VARIOUS VALUES OF L3 AND L6 70 0 ISOLATION vs RF FREQUENCY VARIOUS VALUES OF L3 AND L6 700 10 g g 8 8 8 E 5 L 15nH E z 15 02
17. e 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 50 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 1kQ resistor can be placed in series at the LOSEL to limit the input current in applica tions where LOSEL is applied before Vcc The main and diversity channels incorporate a two stage 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 match ing 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 com bined with the integrated IF amplifiers the cascaded IIP3 2RF 2LO rejection and NF performance are typi cally 28 5dBm 77dBc and 10 5dB respectively Differe
18. h drive level to each mixer core reducing the LO drive required at the MAX9985 s inputs to a 3dBm to range The IF ports for both channels incorporate differ ential 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 chan nels are internally matched to 50 requiring no exter nal 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 7OOMHz 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 befor
19. ntial IF The MAX9985 has 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 applica tions require a 4 1 impedance ratio balun to transform the 2000 differential IF impedance to a 509 single ended system After the balun the IF return loss is bet ter 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 500 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 2000 differential For evaluation an external low loss 4 1 impedance ratio balun transforms this impedance to a 50Q single ended output see the Typical Application Circuit MAXIM Dual SiGe High Linearity 7OOMHz to 1000MHz Downconversion Mixer with LO Buffer Switch LO Buffer Bias Resistors Bias currents for the two on chip LO buffers is opti mized by fine tuning the off chip resistors on LODBIAS pin 17 and LOMBIAS pin 29 The c
20. ormation 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 MAXIM is registered trademark of Maxim Integrated Products Inc S866XVIN
21. s over any one of three frequency bands fnr 824MHz to 849MHz fnr 869MHz to 894MHz 880 to 915MHz Conversion Gain Flatness 2 MAXI Dual SiGe High Linearity 7OOMHz 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 500 sources PLo 3dBm to 3dBm 5dBm fnr 820MHz to 920 2 fi o 670MHz to 865MHZz fip 100MHz gt 40 C to 85 C Typical values are at Voc 5 0V PRF 5dBm Pio OdBm fnr 870 2 fi o 770MHZz fip 100 2 25 C unless otherwise noted Note 1 PARAMETER SYMBOL CONDITIONS Noise Figure Single Sideband Noise Figure under Blocking Condition Input Compression Point Output Compression Point NF fip 190 2 no blockers present Note 3 11dBm blocker tone applied to RF port at 961MHz far 860 2 fi o 670MHz firpesiRED 190MHz fBLOCKER 291MHz Notes 3 4 Small Signal Compression under Blocking Conditions 5dBm fnr 870 2 fB OCKER 871MHz PBLOCKER 8dBm PBLOCKER 11dBm ird Order Input Intercept Point fRF1 fRF2 1 2 fip 100 2 5dBm tone ird Order Input Intercept Point riation over Temperature ird Order Output Intercept int 5dBm tone fip 100 2 fRF4 fRF2 1MHz Note 3
22. urrent 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 IF Amplifier Bias Resistors Bias currents for the two on chip IF amplifiers are opti mized 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 LEXT Inductor Short LEXT_ to ground using a OQ resistor For applica tions 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
23. ut Return Loss LO port unselected 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 far 820MHz to 920 2 fi o 670MHz to 865 2 and fip 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 Typical Operating Characteristics Using the Typical Application Circuit Vcc 5 0V PLO OdBm Pnr 5dBm fnr gt fip 100MHz Tc 25 C unless other wise noted CONVERSION GAIN vs RF FREQUENCY CONVERSION GAIN vs RF FREQUENCY CONVERSION GAIN vs RF FREQUENCY MAX9985 10201 9985 1002 9985 toc03 3dBm OdBm 3dBm Voc 4 75V 5 0V 5 CONVERSION GAIN dB a CONVERSION GAIN dB CONVERSION GAIN dB 5 Tc 485 C Te 425 C 5
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MAXIM MAX9985 handbook