CML Microcircuits
COMMUNICA
TION SEMICONDUCTORS
D/991_992/20 February 2015
CMX991/CMX992
RF Quadrature Transmitter and
RF Quadrature/Low IF Receiver
Provisional Issue
This document describes two separate, high performance, RF ICs covering the range: 100MHz
1
to 1GHz.
The CMX991 is an RF Quadrature Transceiver and the CMX992 is an RF Quadrature Receiver.
Features
Rx (CMX991 and CMX992)
o
RF mixer with output select
o
1st IF input select
o
Selectable low IF outputs
(450kHz/455kHz)
o
1st IF Variable Gain Amplifier (VGA)
o
1st IF Signal Level Indicator (SLI)
o
Two-mode demodulator
o
I/Q Zero-IF with differential outputs
Tx (CMX991 only)
o
I/Q modulator to IF
o
Image-reject up-converter
o
IF and RF outputs
IF (CMX991 and CMX992)
o
IF LO synthesiser
o
IF VCO negative resistance amplifier
3.3V low power operation
Applications
Analogue/digital multimode radio
Software Defined Radio (SDR)
Portable, mobile and base station terminals
Data telemetry modems
TETRA (CMX992)
ETSI: EN 300 113, EN 301 166, EN 302 561,
EN 300 220, TS 102 361 (DMR)
Automatic Identification System (AIS)
transponders
Constant envelope and linear modulation
Compatible with CMX998 (CMX992 only)
Narrowband: e.g. 25kHz, 12.5kHz, 6.25kHz
Wideband: up to 2MHz
APCO Project 25 (P25) Phase 1 and Phase 2
TDMA: TIA-102.CAAB
Satellite communications
1
Brief Description
The CMX991 is a single-chip, high performance, RF transceiver that provides the core functions required
to implement a full-featured radio transmitter and receiver. It operates from 100MHz to 1GHz and its I/Q
architecture supports multiple modulation types and bandwidths with a single radio design. The half-duplex
CMX991 integrates Tx modulators, Rx demodulators, IF PLL and IF VCO subsystems to minimise the
external circuits needed when implementing a complete transceiver. User-selected modes suit different
application requirements.
The Tx path includes an I/Q modulator to accurately generate modulation at the IF frequency, which may
then be translated to the final RF frequency by an integrated image-reject up-converter system. The I/Q
modulator IF output is also made available for conversion to RF via external circuits, if desired.
The Rx path includes an integrated 1 Rx mixer having two outputs to support two external 1 IF filter
choices, then an integrated 2:1 input mux followed by VGA and wideband signal level measurement
st
functions, to support AGC implementation. The 1 IF signal is then either I/Q demodulated to Zero-IF or
mixed to a Low IF output. The CMX991 provides differential and single-ended Rx output options and
differential amplifiers for flexible signal conditioning.
The CMX992 is a single-chip, high performance, RF receiver that includes the core RF and IF receive
functions of the CMX991 above and can be used in a wide range of narrowband and wideband wireless
products, including multi-mode analogue/digital terminals.
The CMX992 can be used where highly linear modulations are being used, e.g. for applications such as
TETRA, where a typical transmitter solution would include the CMX998 Cartesian Feedback Transmitter.
Both devices operate from a single 3.3V supply over a temperature range of -40°C to +85°C and are
available in 48-pin VQFN (Q3) packages.
1 The CMX991/CMX992 may be used at lower frequencies by using appropriate external components. Use below 100MHz is
covered in a separate application note available from the CML website.
st
st
2015 CML Microsystems Plc
RF Quadrature Transceiver / RF Quadrature Receiver
CMX991/CMX992
IF Output
T/R
Power Amplifier
(VC)TCXO
Integer-N
PLL
External
Resonator &
Varactors
Differential
Amplifiers
Tx
I/Q
Input
Div
Power
Supply
Control
Registers
C-BUS
LO Input
LO Input
Div
/4
CMX991
LNA
Rx
Level
IF Filters
2 x IF (e.g 455kHz) Outputs
or I/Q Outputs
Figure 1 CMX991 – RF Quadrature Transceiver
Integer-N
PLL
External
Resonator &
Varactors
Differential
Amplifiers
Control
Registers
Power
Supply
C-BUS
LO Input
Div
/4
CMX992
T/R
SLI
From Transmitter
2 x IF (e.g 455kHz) Outputs
or I/Q Outputs
IF Filters
Figure 2 CMX992 – RF Quadrature/Low IF Receiver
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D/991_992/20
RF Quadrature Transceiver / RF Quadrature Receiver
CMX991/CMX992
CONTENTS
Section
1
2
3
4
4.1
4.2
4.3
4.4
4.5
5
5.1
5.2
5.3
5.4
5.5
5.6
6
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
6.9
7
Page
Brief Description .................................................................................................. 1
1.1
History .............................................................................................................. 6
Block Diagrams .................................................................................................... 7
Pin List .................................................................................................................. 8
3.1
Signal Definitions ............................................................................................. 9
External Components ........................................................................................ 10
Power Supply Decoupling .............................................................................. 10
Receiver (CMX991 and CMX992) ................................................................. 11
Transmitter (CMX991 only)............................................................................ 15
Main Local Oscillator ..................................................................................... 16
IF Local Oscillator (CMX991 and CMX992)................................................... 17
General Description ........................................................................................... 19
Overview ........................................................................................................ 19
Receiver ......................................................................................................... 19
Transmitter (CMX991 only)............................................................................ 21
Local Oscillators ............................................................................................ 22
V
BIAS
............................................................................................................... 24
Data Interface ................................................................................................ 24
C-BUS Interface and Register Description ...................................................... 25
General Reset Command (CMX991/CMX992) ............................................. 27
General Control Register (CMX991/CMX992)............................................... 27
Rx Control Register (CMX991/CMX992) ....................................................... 28
Rx Mode Register (CMX991/CMX992).......................................................... 29
Tx Control Register (CMX991 only) ............................................................... 30
Tx Mode Register (CMX991 only) ................................................................. 31
Tx Gain Register (CMX991 only) ................................................................... 31
IF PLL M Divider (CMX991/CMX992) ............................................................ 32
PLL N Divider (CMX991/CMX992) ................................................................ 33
Application Notes ............................................................................................... 34
7.1
General .......................................................................................................... 34
7.2
Using the CMX992 with the CMX998 ............................................................ 34
7.3
Receiver Gain Issues ..................................................................................... 34
7.4
Oscillator Components for Alternative Intermediate Frequencies. ................ 35
7.5
RF Mixer Input Matching ................................................................................ 36
7.6
RF Mixer IF Output Matching......................................................................... 36
7.7
IF Input Matching ........................................................................................... 37
7.8
Signal Level Indicator (SLI) ............................................................................ 39
7.9
Receiver Spurious Rejection Performance .................................................... 41
7.10
Receiver I/Q Filters ........................................................................................ 42
7.11
Modulation Accuracy...................................................................................... 42
7.12
Post I/Q Modulator Filter ................................................................................ 44
7.13
Variation in I/Q dc Offset with Temperature .................................................. 46
Performance Specification ................................................................................ 47
8.1
Electrical Performance................................................................................... 47
8.2
Packaging ...................................................................................................... 56
8
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RF Quadrature Transceiver / RF Quadrature Receiver
CMX991/CMX992
Table
Page
Table 1 Pin List ................................................................................................................... 9
Table 2 Definition of Power Supply and Reference Voltages ............................................. 9
Table 3 Decoupling Components ..................................................................................... 10
st
Table 4 Typical Rx 1 Mixer Input Matching Components for 455MHz ........................... 11
st
Table 5 1 IF Filtering Components for 45MHz ............................................................... 13
Table 6 Rx I/Q Differential to Single Ended Amplifier Components ................................. 13
Table 7 Rx Low IF (455kHz) Components ....................................................................... 14
Table 8 Transmitter Components..................................................................................... 15
Table 9 I/Q Modulator Output Matching Components ...................................................... 16
Table 10 Rx LO Input Components .................................................................................. 16
Table 11 IF VCO LO Internal VCO Amplifier Tank Circuit for 180MHz Operation ........... 17
rd
Table 12 IF LO 3 Order Loop Filter Circuit for 180MHz Operation ................................ 18
Table 13 Typical Receiver Gain Partitioning .................................................................... 34
Table 14 Typical IF VCO Circuit Values for a Variety of IF Frequencies ......................... 35
Table 15 Receiver Input Match Circuit for Other Operating Frequencies ........................ 36
Table 16 MIXOUT Equivalent Impedances ...................................................................... 37
Table 17 Noise Figure and Gain of IF Amp, VGA, I/Q Mixer and Baseband Filters ........ 38
Table 18 IFIP1 Port Impedance (Parallel Equivalent Circuit Models) .............................. 38
Table 19 IF Noise Figure Measurements at 45 MHz ....................................................... 39
Table 20 Symbol/Error Table for the Tx with 9.6kbps GMSK from an EV9100 ............... 44
Figure
Page
Figure 1 CMX991 – RF Quadrature Transceiver ............................................................... 2
Figure 2 CMX992 – RF Quadrature/Low IF Receiver ........................................................ 2
Figure 3 CMX991 Block Diagram ....................................................................................... 7
Figure 4 CMX992 Block Diagram ....................................................................................... 7
Figure 5 Recommended Power Supply Connections and Decoupling............................. 10
st
Figure 6 Example External Components – Receive 1 Mixer Input ................................. 11
st
Figure 7 Example External Components – Receive 1 IF Section .................................. 12
Figure 8 Example External Components – Receive I/Q Output ....................................... 13
Figure 9 Example External Components – Receive Low IF Output ................................. 14
Figure 10 Example External Components – Transmitter ................................................. 15
Figure 11 Example External Components – I/Q Modulator Output .................................. 16
Figure 12 Example External Components – Rx LO Input ................................................ 16
Figure 13 Example External Components – IF LO VCO External Tank Circuit ............... 17
Figure 14 Example External Components – IF LO Loop Filter ........................................ 18
Figure 15 DC Offset Calibration Mode ............................................................................. 20
Figure 16 CMX991 Transmitter Architecture.................................................................... 21
Figure 17 CMX991/CMX992 IF Local Oscillator .............................................................. 22
Figure 18 Typical LO Input Impedance ............................................................................ 23
Figure 19 C-BUS Transactions ........................................................................................ 26
Figure 20 Receiver Gain Control ...................................................................................... 35
Figure 21 Receiver Matching Components ...................................................................... 36
Figure 22 MIXOUT1 Port Impedance (unmatched) ......................................................... 37
Figure 23 IFIP1 Input Impedance at 0dB attenuation....................................................... 38
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D/991_992/20
RF Quadrature Transceiver / RF Quadrature Receiver
CMX991/CMX992
Figure 24
Figure 25
Figure 26
Figure 27
Figure 28
Figure 29
Figure 30
Figure 31
Figure 32
Figure 33
Typical SLI Performance .................................................................................. 40
Typical SLI Performance in an Application Circuit (EV9920B) ......................... 40
IF Output Response with and without Blocking Signal Present ....................... 41
Typical Receiver I/Q Frequency Response ...................................................... 42
Tx Output with 9.6kbps GMSK from an EV9100.............................................. 43
Transmitter Path IF Filters ............................................................................... 45
Transmitter IF Output Showing Filter Responses with IFH bit = ‘1’ ................. 45
Effect of IFH on 45MHz and 60MHz Transmitter IF Filters .............................. 46
C-BUS Timing .................................................................................................. 55
Q3 Mechanical Outline: .................................................................................... 56
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D/991_992/20
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