AN RFMD® APPLICATION NOTE RFFC507x Application Note Mixer Performance Above 4GHz Introduction The RFFC5071 and RFFC5072 are wideband frequency conversion devices that integrate a fractional-N synthesizer and one or two RF mixers. The mixer ports are very wideband and cover from 30MHz to 6000MHz, enabling up or down conversion. The RFFC5071/5072 datasheet contains test results for the RF mixers up to frequencies of 4GHz. This application note presents further test results for frequencies above 4GHz. The application circuits used on the mixer ports for these measurements are also shown. RF MICRO DEVICES®, RFMD®, Optimum Technology Matching®, Enabling Wireless Connectivity™, PowerStar®, POLARIS™ TOTAL RADIO™ and UltimateBlue™ are trademarks of RFMD, LLC. BLUETOOTH is a trademark owned by Bluetooth SIG, Inc., U.S.A. and licensed for use by RFMD. All other trade names, trademarks and registered trademarks are the property of their respective owners. ©2010, RF Micro Devices, Inc. AN110606 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or [email protected]. 1 of 5 RFFC507x Application Note RF Frequency Range 3100MHz to 4800MHz The following ceramic hybrid balun was used on the RF ports of the mixer: Johanson Technology, 4000BL14U100, 50 to 100, 3100MHz to 4800MHz The mixer has a broadband common gate input, with real impedance of around 75 to 85, dependant on mixer current setting. The above balun used on the down conversion input gives good wideband performance without any further matching. An output frequency of 1000MHz was selected for the down conversion tests, using the RFXF8553 4:1 transmission line transformer. A 33nH shunt inductor resonates with the mixer output capacitance to give best conversion gain at the 1000MHz IF output. For the up conversion tests a 1000MHz input frequency was used, with the RFXF9503 1:1 transmission line transformer. For the mixer output a 4:1 balun is usually recommended to give best gain, presenting a 200 load to the mixer. However as frequency increases the effect of the mixer output capacitance (approximately 0.8pF) becomes more significant, rolling off gain, and is harder to match out effectively. Reducing the mixer output load using the 50 to 100 balun offers a good compromise since it reduces the effect of the output capacitance. The disadvantage of the 4000BL14U100 balun when used on the mixer output is that its phase imbalance increases rapidly above 4GHz, with the result that the common mode rejection ratio (CMRR) of the balun is reduced. This means that common mode noise and spur levels at the output will increase as the balun CMRR reduces. Mixer 1 - Down Conversion RF Input Mixer 1 - Down Conversion IF Output VDDA 100p 8p2 RF Input 100p 1 50 : 100 LTCC Balun 3100MHz to 4800MHz UnB Gnd Bal NC Gnd Bal RFFC5071 Mixer 1 Input RFFC5071 Mixer 1 Output IF Output 1GHz 33nH 100p 4:1 Balun RFXF8553 8p2 Mixer 2 - Up Conversion IF Input Mixer 2 - Up Conversion RF Output 4p7 VDDA 12p RFXF9503 1:1 Balun IF Input 1GHz 100p RFFC5071 Mixer 2 Input RF Output 1 UnB Gnd Bal Gnd Bal RFFC5071 Mixer 2 Output 100p 50 : 100 LTCC Balun NC 3100MHz to 4800MHz Note: The results overpage are measured between SMA connectors on the FC5071410(2) evaluation board, BOM modified as shown above. The results include all balun and PCB losses. AN110606 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or [email protected]. 2 of 5 RFFC507x Application Note Typical results for the RFFC5071 mixers from 3100MHz to 4800MHz Mixer Conversion Gain IF = 1000MHz, LO = RF - IF 0.0 Mixer 1 - Down Conversion -2.0 Mixer 2 - Up Conversion Gain (dB) -4.0 -6.0 -8.0 -10.0 -12.0 -14.0 -16.0 2500 3000 3500 4000 4500 5000 5500 Mixer 1 Down Conversion Input IP3 Mixer 2 Up Conversion Input IP3 IFOUT = 1000MHz, LO = RF - IF, 3V Supply IFIN = 1000MHz, LO = RF - IF, 3V Supply 30.0 30.0 25.0 25.0 Input IP3 (dBm) Input IP3 (dBm) RF Frequency (MHz) 20.0 3100MHz 3600MHz 4100MHz 4400MHz 4800MHz 15.0 20.0 3100MHz 3600MHz 4100MHz 15.0 4400MHz 4800MHz 10.0 10.0 1 2 3 4 5 6 7 1 Mixer Current Setting (MIX1_IDD) 2 3 4 5 6 7 Mixer Current Setting (MIX2_IDD) Mixer 1 Down Conversion Noise Figure Mixer 2 Up Conversion Noise Figure IFOUT = 1000MHz, LO = RF - IF IFIN = 1000MHz, LO = RF - IF 20.0 25.0 18.0 20.0 14.0 MIX_IDD = 1 MIX_IDD = 2 12.0 MIX_IDD = 3 MIX_IDD = 4 10.0 MIX_IDD = 5 MIX_IDD = 6 8.0 Noise Figure (dB) Noise Figure (dB) 16.0 15.0 MIX_IDD = 1 10.0 MIX_IDD = 2 MIX_IDD = 3 MIX_IDD = 4 5.0 MIX_IDD = 5 MIX_IDD = 6 MIX_IDD = 7 6.0 2500 3000 3500 4000 4500 5000 RF Input Frequency (MHz) AN110606 5500 MIX_IDD = 7 0.0 3600 3700 3800 3900 4000 4100 4200 4300 4400 RF Output Frequency (MHz) 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or [email protected]. 3 of 5 RFFC507x Application Note RF Frequency Range 4900MHz to 5900MHz The following ceramic hybrid balun was used on the RF ports of the mixer: Johanson Technology, 5400BL15B050, 50 to 50, 4900MHz to 5900MHz The mixer has a broadband common gate input, with real impedance of around 75 to 85, dependant on mixer current setting. The above balun used on the down conversion input gives good performance from 4900MHz to above 5900MHz without any further matching. An output frequency of 1750MHz was selected for the down conversion tests, using the RFXF8553 4:1 transmission line transformer. An 8.2nH shunt inductor resonates with the mixer output capacitance to give best conversion gain at the 1750MHz IF output. For the up conversion tests input frequencies of 1750MHz and 2000MHz were used, with the RFXF9503 1:1 transmission line transformer. For the mixer output above 5GHz reducing the mixer output load using the 50 to 50 balun above was found to give best gain since it reduces the effect of the output capacitance. The IF of above 1700MHz was chosen since it enables the maximum RF frequency of 5900MHz to be achieved with the maximum specified LO frequency of the RFFC507x devices of 4200MHz. Note that the RFXF8553 and RFXF9503 transformers will be more lossey above 1700MHz. Mixer 1 - Down Conversion RF Input Mixer 1 - Down Conversion IF Output VDDA 100p 2p2 RF Input 100p 1 UnB 50 : 50 LTCC Balun 5400MHz +/- 500MHz NC Gnd Gnd Bal RFFC5071 Mixer 1 Input Bal RFFC5071 Mixer 1 Output IF Output 1750MHz 8.2nH 100p 4:1 Balun RFXF8553 2p2 Mixer 2 - Up Conversion IF Input Mixer 2 - Up Conversion RF Output 2p2 VDDA RFXF9503 1:1 Balun RF Output IF Input 1750MHz 100p 100p RFFC5071 Mixer 2 Input 1 UnB Gnd Bal RFFC5071 Mixer 2 Output 50 : 50 LTCC Balun NC 5400MHz +/- 500MHz Gnd Bal 2p2 Note: The results overpage are measured between SMA connectors on the FC5071410(2) evaluation board, BOM modified as shown above. The results include all balun and PCB losses. AN110606 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or [email protected]. 4 of 5 RFFC507x Application Note Typical results for the RFFC5071 mixers from 4900MHz to 5900MHz Mixer Conversion Gain Mixer 2 Up Conversion Noise Figure IF = 1750MHz, LO = RF - IF MIX2_IDD= 4, LO = RF - IF 30.0 0.0 IF in = 1750MHz Mixer 1 - Down Conversion -2.0 25.0 Mixer 2 - Up Conversion IF in = 2000MHz Noise Figure (dB) Gain (dB) -4.0 -6.0 -8.0 -10.0 -12.0 20.0 15.0 10.0 5.0 -14.0 -16.0 4500 4750 5000 5250 5500 5750 6000 0.0 4750 6250 5000 5750 Mixer 1 Down Conversion Input IP3 Mixer 2 Up Conversion Input IP3 IFIN = 2000MHz, LO = RF - IF, 3V Supply 30.0 30.0 25.0 25.0 Input IP3 (dBm) Input IP3 (dBm) 5500 IFOUT = 1750MHz, LO = RF - IF, 3V Supply 20.0 4900MHz 5150MHz 5400MHz 5650MHz 5900MHz 15.0 6000 20.0 4900MHz 15.0 5400MHz 5900MHz 10.0 10.0 1 2 3 4 5 6 7 1 Mixer Current Setting (MIX1_IDD) 3 4 5 7 IFIN = 2000MHz, LO = RF - IF 26.0 22.0 24.0 20.0 22.0 Noise Figure (dB) 24.0 18.0 16.0 4900MHz 20.0 18.0 16.0 4900MHz 5400MHz 12.0 6 Mixer 2 Up Conversion Noise Figure IFOUT = 1750MHz, LO = RF - IF 14.0 2 Mixer Current Setting (MIX2_IDD) Mixer 1 Down Conversion Noise Figure Noise Figure (dB) 5250 RF Output Frequency (MHz) RF Frequency (MHz) 5400MHz 14.0 5900MHz 10.0 5900MHz 12.0 1 2 3 4 5 6 Mixer Current Setting (MIX1_IDD) AN110606 7 1 2 3 4 5 6 7 Mixer Current Setting (MIX2_IDD) 7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical support, contact RFMD at (+1) 336-678-5570 or [email protected]. 5 of 5