CMX993/CMX993W CML Microcircuits 30MHz 1GHz COMMUNICATION SEMICONDUCTORS Quadrature Modulator D/993/12 May 2021 Provisional Issue This document describes two separate, high performance, RF quadrature modulator ICs: The standard CMX993 and the wide bandwidth CMX993W product variant. Features Applications 30MHz to 1GHz Operating Frequency APCO P25, Wireless Data Wide Band Noise 148dBc/Hz ISM Transmitters Noise Floor 155dBm/Hz Digital TV/CATV Modulators Programmable 30dB Output Gain Range Wireless LAN, Wireless Local Loop +3dBm (PEP) Output Power IF or RF Modulators Low LO Drive Requirements, -15dBm FSK, GMSK, 4FSK, C4FM Uncommitted Amplifiers for Filtering and QPSK, QAM, SSB, OFDM, Interfacing Multi-carrier Systems CMX993W Wide Bandwidth Version SDR (Software Defined Radios) (>50MHz I/Q Bandwidth) WiMAX Systems C-BUS (SPI Compatible) Serial Interface OFDM/COFDM Systems Low Voltage 3.3V Operation Satellite Communications Small 7x7mm VQFN Package (Q3) Cellular Picocell / Nanocell Systems +25dBm Equivalent Output IP3 RF Channel Bandwidths up to 100MHz Input Amplifiers Filter/Interface I/Q Mixer and Gain Control Amplifiers I Channel I/Q MOD Output Q Channel 0 Bandgap V REF Divide by 2 or LO Input 90 Divide by 4 Control C-BUS Interface 1 Brief Description The CMX993 and CMX993W are integrated, low voltage quadrature (I/Q) modulator ICs suitable for use in applications operating from 30MHz to 1000MHz. The devices integrate two matched double balanced mixers driven from a buffered and quadrature split local oscillator. The LO frequency is divided by either 2 or 4. The mixers form an I/Q vector modulator with programmable gain stages offering up to 30dB of gain, controlled in 2.5dB steps. Uncommitted low frequency differential amplifiers are provided for users to configure. These may be used to implement functions such as filtering, differential- to single-ended signal conversion and level shifting. The CMX993W product variant offers wide-bandwidth operation. A digital control interface, C-BUS, (an SPI compatible interface) allows gain control as well as power management of individual internal blocks to optimise system performance. The C-BUS interface operates from its own supply domain enabling the device to be interfaced to different voltage baseband devices. The CMX993 and CMX993W devices are supplied in RF optimised VQFN packages. 2021 CML Microsystems Plc Quadrature Modulator CMX993/CMX993W CONTENTS Section Page 1 Brief Description .................................................................................................. 1 1.1 History............................................................................................................. 3 2 Block Diagrams .................................................................................................... 4 3 Signal List ............................................................................................................. 5 3.1 Signal Definitions .......................................................................................... 6 4 External Components .......................................................................................... 7 4.1 Power Supply Decoupling ............................................................................ 7 4.2 Quadrature Modulator ................................................................................... 8 4.3 Local Oscillator Input .................................................................................. 10 5 General Description ........................................................................................... 11 5.1 Quadrature Modulator ................................................................................. 11 5.2 Differential Amplifiers.................................................................................. 11 5.3 Reference Voltages ..................................................................................... 12 5.4 Data Interface ............................................................................................... 12 6 C-BUS Interface and Register Description ...................................................... 13 6.1 General Reset Command: C-BUS address 01 ....................................... 13 6.2 General Control Register: C-BUS address 02 8-bit write-only ............ 14 6.3 Gain Control Register: C-BUS address 05 8-bit write-only ................ 14 6.4 Frequency Control Register: C-BUS address 08 8-bit write-only ....... 15 7 Application Notes ............................................................................................... 16 7.1 Typical Performance ................................................................................... 16 7.2 Intermodulation and Modulator Spurious ................................................. 18 8 Performance Specification ................................................................................ 20 8.1 Electrical Performance ................................................................................ 20 8.2 Packaging ..................................................................................................... 26 2021 CML Microsystems Plc 2 D/993/12