CMX971Q7

CBUS logic CMX971 CML Microcircuits Quadrature Modulator COMMUNICATION SEMICONDUCTORS D/971/5 February 2019 Provisional Issue Features Applications 20 1000MHz RF Output Wireless Data Terminals 0dBm Output HF/VHF and UHF Mobile Radio 25MHz I/Q Bandwidth Avionics Radio Systems Serial Bus or Direct Control Operation Low Power 3.0V 3.6V Operation Small 16-lead VQFN Package TXIN TXQP TXQN CBUSOFFN TXIP VSS CSN/ RFOUT FREQ2 RDATA/ RFGND DIVSET Divide by 2 or 4 SCLK/ VCC RESETN CDATA/ LO LOGND VDD FREQ1 1 Brief Description The CMX971 is a high performance quadrature modulator featuring a wide operating frequency range and attractive power consumption. Control of the CMX971 may be either by serial bus or by direct control (with reduced functionality). Programmable features include the local oscillator divider ratio (2 or 4). The small, RF-optimised VQFN package and minimal external components make the device ideal for space- constrained applications. 2019 CML Microsystems Plc Quadrature Modulator CMX971 CONTENTS Section Page 1 Brief Description .................................................................................................. 1 1.1 History .............................................................................................................. 3 2 Block Diagram ...................................................................................................... 4 3 Pin and Signal List ............................................................................................... 5 3.1 Main Functions ................................................................................................ 5 3.2 Direct Control Functions .................................................................................. 5 4 External Components .......................................................................................... 6 4.1 Power Supply Decoupling ................................................................................ 6 4.2 Quadrature Modulator ...................................................................................... 7 4.3 Local Oscillator (LO) Input ............................................................................... 7 5 General Description ............................................................................................. 8 5.1 Programmable Data Interface ......................................................................... 8 5.2 Quadrature Modulator ...................................................................................... 8 5.2.1 DC Offsets and Carrier Leakage ............................................................... 8 5.3 Local Oscillator ................................................................................................ 8 6 C-BUS Interface and Register Description ........................................................ 9 6.1 General Reset Command .............................................................................. 10 6.1.1 General Reset Command C-BUS address 1A ...................................... 10 6.2 General Control Register ............................................................................... 11 6.2.1 General Control Register: C-BUS address 1B ...................................... 11 6.2.2 General Control Register C-BUS address EB ....................................... 11 6.3 Control Register ............................................................................................. 11 6.3.1 Control Register: C-BUS address 1E .................................................... 11 6.3.2 Control Register C-BUS address EE .................................................... 12 7 Direct Control Option ......................................................................................... 13 8 Application Notes ............................................................................................... 15 8.1 Impedance Matching Information .................................................................. 15 8.1.1 LO Input ................................................................................................... 15 8.2 Modulator Operation ...................................................................................... 15 8.2.1 Quadrature Accuracy .............................................................................. 16 8.2.2 Wideband Noise ...................................................................................... 18 8.2.3 Harmonics ............................................................................................... 19 9 Performance Specification ................................................................................ 20 9.1 Electrical Performance................................................................................... 20 9.1.1 Absolute Maximum Ratings (CMX971 & CMX971A) .............................. 20 9.1.2 Operating Limits (CMX971 & CMX971A) ............................................... 20 9.1.3 Operating Characteristics ........................................................................ 21 9.2 Packaging ...................................................................................................... 25 2019 CML Microsystems Plc 2 D/971/5