CMX973Q5

CMX973 CML Microcircuits Quadrature Modulator/Demodulator COMMUNICATION SEMICONDUCTORS D/973/12 April 2019 Provisional Issue Features Applications 20 300MHz IF/RF Demodulator Wireless Data Terminals 10MHz Rx and 25MHz Tx I/Q Bandwidth HF/VHF and UHF Mobile Radio 20 1000 MHz RF Modulator Avionics Radio Systems 0dBm Modulator Output Telemetry Modems < 1 degree I/Q Phase Matching Wireless Microphones < 0.5 dB I/Q Gain Matching Software Defined Radio (SDR) Low Power, 3.0V 3.6V Operation Satellite Terminals Small 32-lead VQFN Package VCO VCO VCO VCO TXIN RXLO OA1O OA1N P2 P1 N1 N2 TXIP OA1P VCO 40-1000MHz TXQP VSS Quadrature transmitter TXQN CSN RFOUT OA2O Local oscillator switching IFIN OA2N VCC OA2P Quadrature demodulator RXIN RDATA Serial bus PLL and control RXIP SCLK VCC RXQP RXQN TXLO REFIN DO CDATA VDD SYNTH 1 Brief Description The CMX973 integrates a quadrature (I/Q) modulator and a low-power quadrature IF/RF demodulator, both featuring a wide operating frequency range and optimised power consumption. The demodulator is suitable for superheterodyne architectures with IF frequencies up to 300MHz and the device may be used in low IF systems or those converting down to baseband. The modulator converts directly from baseband to the desired transmit frequency and features quadrature phase correction to minimise unwanted spectral components. An on-chip PLL and VCO, together with uncommitted baseband differential amplifiers, provide additional flexibility. Control of the CMX973 is by serial bus. The CMX973 is supplied in an RF- optimised 32-lead VQFN package. 2019 CML Microsystems Plc Quadrature Modulator/Demodulator CMX973 CONTENTS Section Page 1 Brief Description .................................................................................................. 1 1.1 History .............................................................................................................. 4 2 Block Diagram ...................................................................................................... 5 3 Pin List .................................................................................................................. 6 4 External Components .......................................................................................... 7 4.1 Power Supply Decoupling ............................................................................... 7 4.2 Quadrature Modulator...................................................................................... 8 4.3 Quadrature Demodulator ................................................................................. 8 4.4 Local Oscillator (LO) Input ............................................................................... 9 4.5 VCO and PLL ................................................................................................... 9 4.6 Differential Amplifiers ..................................................................................... 12 4.6.1 I/Q Output Amplifiers ............................................................................... 12 4.6.2 Low IF Output .......................................................................................... 13 5 General Description ........................................................................................... 14 5.1 Quadrature Modulator.................................................................................... 14 5.1.1 Local Oscillator (LO) ............................................................................... 14 5.1.2 DC Offsets and Carrier Leakage ............................................................. 14 5.2 Quadrature Demodulator ............................................................................... 14 5.2.1 I/Q Amplitude and Phase Correction ...................................................... 15 5.2.2 DC Offset Correction ............................................................................... 17 5.3 Differential Amplifiers ..................................................................................... 17 5.4 Local Oscillator (LO) ...................................................................................... 18 5.4.1 Demodulator LO Input ............................................................................. 18 5.4.2 Modulator LO Input ................................................................................. 18 5.4.3 VCO and PLL .......................................................................................... 19 6 C-BUS Interface and Register Description ...................................................... 21 6.1 General Reset Command .............................................................................. 22 6.1.1 General Reset Command - 1A: no data ................................................ 22 6.2 General Control Register ............................................................................... 23 6.2.1 General Control Register - 1B: 8-bit write ............................................. 23 6.2.2 General Control Register - EB: 8-bit read ............................................. 23 6.3 Rx Control Register ....................................................................................... 23 6.3.1 Rx Control Register - 1C: 8-bit write ..................................................... 23 6.3.2 Rx Control Register - EC: 8-bit read ..................................................... 24 6.4 Rx Mode Register .......................................................................................... 24 6.4.1 Rx Mode Register - 1D: 8-bit write ........................................................ 24 6.4.2 Rx Mode Register - ED: 8-bit read ........................................................ 25 6.5 Tx Control Register ........................................................................................ 25 6.5.1 Tx Control Register - 1E: 8-bit write ...................................................... 25 6.5.2 Tx Control Register - EE: 8-bit read ...................................................... 26 6.6 Rx Offset Register ......................................................................................... 27 6.6.1 Rx Offset Register - 1F: 8-bit write ........................................................ 27 6.6.2 Rx Offset Register - EF: 8-bit read ........................................................ 27 6.7 PLL M Divider ................................................................................................ 28 6.7.1 PLL M Divider - 2C - 2A: 8-bit write .................................................... 28 6.7.2 PLL M Divider - DC - DA: 8-bit read .................................................... 28 6.8 PLL R Divider ................................................................................................. 28 6.8.1 PLL R Divider - 2E - 2D: 8-bit write ..................................................... 28 2019 CML Microsystems Plc 2 D/973/12