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CMX994: 产品描述Local Oscillator; 文件大小2MB，共61页; 制造商CML Microcircuits; 官网地址http://www.cmlmicro.com/

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CMX994概述

Local Oscillator

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CML Microcircuits

COMMUNICA

TION SEMICONDUCTORS

CMX994/CMX994A/CMX994E

Direct Conversion Receivers

CMX994 / CMX994A (lower power consumption) / CMX994E (enhanced performance)

D/994_994A_994E/1 September 2015

DATASHEET

Provisional

Features



Direct conversion receiver family with PowerTrade™

flexible power vs. performance modes

CMX994 - Standard and low power modes

CMX994A - Standard and additional low power modes

CMX994E - Enhanced, standard and low power modes



Rx single conversion to zero IF, near-zero IF or low IF; zero

IF eliminates image responses



Very high mixer IIP2 for practical zero IF receiver



100MHz to 1000MHz I/Q demodulator (CMX994A/E)

100MHz to 940MHz I/Q demodulator (CMX994)

Extended operation down to 50MHz



LNA with gain control



Precise filtering with 1:2:4 bandwidth select control



Mixer Bandwidth up to 20MHz



Local Oscillator

LO synthesiser

VCO negative resistance amplifier

Rx LO divide by 2, 4 or 6 modes

Tx LO Output with divide by 1, 2, 4, or 6 modes



3.0V – 3.6V Low power Operation



Small size 40-pin VQFN Package

Applications



Analogue/digital multi-mode radio

Software Defined Radio (SDR)

Data telemetry modems

Satellite communications

Constant envelope and linear modulation

Rx function compatible with CMX998

Cartesian Feedback Loop Transmitter



Narrowband e.g. 25kHz, 12.5kHz, 6.25kHz



Wideband Data e.g. >1MHz bandwidth

I/Q Signals

T/R

CMX994

CMX994A

CMX994E

Ref. Osc.

Tx LO

Baseband

Signal Processing

C-BUS

Reset

Rx Enable

Tx Enable

Direct Conversion Receiver

µC

Flash

Brief Description

The CMX994/CMX994A/CMX994E is a family of direct conversion receiver ICs with PowerTrade™, the ability

to dynamically select power vs. performance modes to optimise operating trade-offs. All three devices

include a broadband LNA with gain control followed by a high dynamic range, very high IIP2, I/Q

demodulator. The receiver baseband section includes amplifiers and precise, configurable bandwidth,

baseband filter stages. LO generation is provided by an integer-N PLL and a VCO negative resistance amplifier;

an external LO may also be used. LO dividers are provided for flexible multi-band operation. The devices

operate from a single 3.3V supply over a temperature range of –40°C to +85°C and are available in a small 40-

pin VQFN (Q4) package.

Relative to the CMX994 the CMX994A enables a significant reduction in power by allowing LO phase

correction to be turned off. A further reduction is made possible by the facility to disable either the I or Q

channel. The CMX994E expands on that by adding an enhanced performance mode that features improved

intermodulation in the receive path mixers.



2015 CML Microsystems Plc

Page 1 of 70

D/994_A_E/1

Direct Conversion Receivers

CMX994/CMX994A/CMX994E

CONTENTS

Section

4.1

4.2

5.1

5.2

5.2.1

5.2.2

5.3

5.3.1

5.3.2

5.4

6.1

6.1.1

6.2

6.2.1

6.2.2

6.2.3

6.2.4

6.3

6.3.1

6.3.2

7.1

7.2

7.2.1

7.2.2

7.3

7.3.1

7.3.2

7.4

7.4.1

7.4.2

7.5

7.5.1

7.5.2

7.6

7.6.1

7.6.2

7.7

7.7.1

7.7.2

7.8

Page

Brief Description...................................................................................................................................... 1

History ..................................................................................................................................................... 5

Block Diagram ......................................................................................................................................... 6

Pin and Signal List .................................................................................................................................... 7

Signal Definitions ............................................................................................................................................8

Connection of Unused Pins .............................................................................................................................8

External Components .............................................................................................................................. 9

Power Supply and Decoupling ........................................................................................................................9

Receiver ..........................................................................................................................................................10

LNA..................................................................................................................................................................10

Mixers and Baseband Section .........................................................................................................................13

Local Oscillator ................................................................................................................................................15

Local Oscillator Input ......................................................................................................................................15

VCO and PLL

..............................................................................................................................................15

RESETN ............................................................................................................................................................16

General Description ................................................................................................................................. 17

General Operation ..........................................................................................................................................18

RX/Tx Enable ..............................................................................................................................................18

Receiver Operation .........................................................................................................................................18

DC Offset Correction .......................................................................................................................................18

Receiver Filters and Bandwidth Options.........................................................................................................19

Baseband Filter Design and Required Correction ...........................................................................................20

Operation at Wider Bandwidths .....................................................................................................................21

Local Oscillator Operation ..............................................................................................................................21

PLL

..............................................................................................................................................22

PLL Enable

..............................................................................................................................................23

C-BUS Interface and Register Descriptions .............................................................................................. 24

General Reset - $10 (no data) .........................................................................................................................25

General Control Register ................................................................................................................................26

General Control - $11 - 8-bit write only ..........................................................................................................26

General Control - $E1 - 8-bit read only ...........................................................................................................26

Rx Control Register .........................................................................................................................................27

Rx Control - $12 – 8-bit write only ..................................................................................................................27

Rx Control - $E2 – 8-bit read only ...................................................................................................................27

Rx Offset Register ...........................................................................................................................................28

Rx Offset - $13 – 8-bit write only ....................................................................................................................28

Rx Offset - $E3 - 8-bit Read only .....................................................................................................................28

Intermodulation Control Register ...................................................................................................................29

IM Control - $14 – 8-bit write only .................................................................................................................29

IM Control - $E4 – 8-bit read only...................................................................................................................29

Rx Gain Register ..............................................................................................................................................31

Rx Gain - $16 – 8-bit write only ......................................................................................................................31

Rx Gain - $E6 – 8-bit read only ........................................................................................................................31

PLL M Divider Register ....................................................................................................................................33

PLL M Divider - $22 - $20 – 8-bit write only....................................................................................................33

PLL M Divider - $D2-$D0 - 8-bit read only ......................................................................................................33

PLL R Divider Register .....................................................................................................................................34

D/994_A_E/1

Page 2 of 70



2015 CML Microsystems Plc

Direct Conversion Receivers

CMX994/CMX994A/CMX994E

7.8.1

7.8.2

7.9

7.9.1

7.9.2

8.1

8.1.1

8.1.2

8.1.3

8.1.4

8.1.5

8.1.6

8.1.7

8.1.8

8.1.9

8.1.10

8.2

8.3

8.4

9.1

9.1.1

9.1.2

9.2.1

PLL R Divider - $24 - $23 – 8-bit write only .....................................................................................................34

PLL R Divider - $D4-$D3 – 8-bit read only .......................................................................................................34

VCO Control Register ......................................................................................................................................35

VCO Control - $25 - 8-bit write only................................................................................................................35

VCO Control - $D5 - 8-bit read only ................................................................................................................35

Application Notes .................................................................................................................................... 36

Typical Receiver Performance ........................................................................................................................36

System Performance .......................................................................................................................................36

DC Offsets .......................................................................................................................................................37

Gain Control ....................................................................................................................................................38

LNA Intermodulation Optimisation ................................................................................................................41

Low Power Mode ............................................................................................................................................42

I/Q Filter Response .........................................................................................................................................42

Baseband Intermodulation .............................................................................................................................43

LO Pulling ........................................................................................................................................................43

Rx Mixer Output (Broadband Operation) .......................................................................................................44

Spurious Responses ........................................................................................................................................45

Operation Below 100MHz...............................................................................................................................46

Transmitter LO Output....................................................................................................................................46

Modem Solutions ............................................................................................................................................48

Performance Specification ....................................................................................................................... 50

Electrical Performance ....................................................................................................................................50

Absolute Maximum Ratings ............................................................................................................................50

Operating Limits..............................................................................................................................................50

Operating Characteristics ...............................................................................................................................51

AC Parameters – Direct Conversion Receiver Sections

....................................................................................54

AC Parameters – Tx Output.............................................................................................................................

AC Parameters – C-BUS

...................................................................................................................................59

Packaging ........................................................................................................................................................60

9.3



2015 CML Microsystems Plc

Page 3 of 70

D/994_A_E/1

CMX994

CMX994概述

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