SmartRF CC400 / CC900

canolaokahumpkaElectronics - Devices

Nov 2, 2013 (4 years and 10 days ago)

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1

SmartRF


CC400 / CC900


Single Chip High Performance RF Transceivers

Peder Martin Evjen, M.Sc.E.E

Field Application Engineer

2

Applications overview


UHF wireless FSK data transmitters and
receivers


LPD, Low Power Devices


SRD, Short Range Devices


ISM, Industrial
-

Scientific
-

Medicine


433 and 418 MHz SRD band systems


868MHz European SRD band


260
-

470 US ISM band


902
-
928 US ISM band

3

Applications overview


Keyless entry with acknowledgement


Telemetry / remote metering of;


electricity, water, gas


temperature, pressure


environment and air quality


Smart House applications


lights, heat, alarms, comfort, electrical equipment


Alarm and security systems


Remote Tagging (RF Tag)


Industrial Remote Controls


lifts, cranes, industrial equipment


“Intelligent” toys



4

Radio transmission system


CC400/900: One
-
chip RF transceiver


FSK modulation (superior to ASK)


Up to 9.6kbps (19.2kbaud)

Data

source

Micro

controller

RF

transceiver

NRZ

(De)coding

Manchester

(De)modulation

FSK

5

CC400/CC900

RF transceiver


Three
-
wire control interface


Data in/out (bi
-
directional)


RF antenna in/out

DIO

PDATA

CLOCK

STROBE

RF

6

Block diagram

7

Receiver features


Low noise front end (3dB noise figure)


High sensitivity

CC400:
-
112dBm @ 1.2kbps,BER=10
-
3

CC900:
-
110dBm @ 1.2kbps,BER=10
-
3


Fully integrated IF stage, no external filters
needed (optional ext. 455kHz)


Selectable IF frequency
(60/200/455kHz)


Fully integrated FSK demodulator, no external
ceramic resonator needed


Data rate 0.3
-

9.6 kbps

8

Transmitter features


Integrated power amplifier

-

CC400:
-
5 to 14dBm (25mW)

-

CC900:
-
20 to 4dBm (2.5mW)


Programmable output power in 1dB steps


Fully integrated FSK modulator with
programmable deviation (1
-
50 kHz)


Internal RX/TX switch

9

Synthesiser features


Cover

300
-
500 MHz (CC400)



800
-
1000 MHz (CC900)


Very fine frequency resolution:


CC400: 5 kHz, CC900: 250 Hz


Free choice crystal frequency

(4
-
13 MHz)


External loop filter for flexibility (optimise to
data
-
rate)


External VCO tank for flexibility


PLL lock signal


10

Chip features


Small package SSOP
-
28


Low supply voltage (2.7
-
3.3 V)


Very low power
-
down/standby current typical
0.2

A


Few external components


Easy to use 3
-
wire control bus for configuration

11

Radio range


CC400: >2000 m


CC900: >500 m


10dBm, quarter wave antenna, 1.2kbps


Key issues:


Sensitivity


Output power


Antenna solution


Interferers / noise


6dB ~ twice the distance

12

Data interface
-

DIO pin


Bi
-
directional data pin (TX:in, RX:out)


Manchester code (a.k.a. bi
-
phase
-
level coding)


-

no DC component





-

timing information


Final data decision by micro
-
controller



-

code available

13

Transmit operation


FSK modulation

frequency

fc

Fc
-
df

Fc+df

DIO=low DIO=high

Frequency separation

= 2 x df

14

Receive operation


Mixing and FSK demodulation

Freq.

fc

Fc
-
df

Fc+df

DIO=low DIO=high

Frequency separation = 2 x df

Frequency deviation = df

IF

IF
-
df

IF+df

LO

Intermediate frequency

15

Configuration


3
-
wire serial bus for configuration


8 control registers of 13 bits each


3 bit address


Totally 16bits x 8registers = 128 bits


Full configuration in 64

s (at 2MHz)


Configuration data generated by SmartRF
Studio (software)

-
no bit trixing

16

How to generate the configuration
data


SmartRF Studio makes it easy:


Enter system parameters





-

carrier frequency





-

frequency seperation





-

IF frequency etc.


‘File’
-

‘Print registers to file’


A file containing all necessary configuration data
is generated

17

Print
-
out example

RX mode:

Frame

Data (hex)

000

002A

001

030B

002

0141

003

051F

004

0A00

005

1A03

006

0B6C

007

0040


TX mode:

Frame

Data (hex)

000

082A

001

030B

002

0141

003

0457

004

0A0A

005

1A03

006

0B6C

007

0040




RX Precharge mode:

Frame

Data (hex)

000

002A

001

030B

002

0141

003

051F

004

0A00

005

1A03

006

0B6C

007

0248



PD osc. on mode:

Frame

Data (hex)

000

102A

001

030B

002

0141

003

051F

004

0A00

005

1A03

006

0B6C

007

0040


PD osc. off mode:

Frame

Data (hex)

000

102A

001

030B

002

0151

003

051F

004

0A00

005

1A03

006

0B6C

007

0040


18

3
-
wire serial interface


Up to 2MHz clock frequency


3 bit register address sent first


MSB of data sent first


19

Wiring up the circuit, CC400

20

Wiring up the circuit, CC900

21

External components


Crystal (tolerance, drift, ageing, load)


Input/output matching network

-

see SmartRF Studio


PLL loop filter (data rate)

-

see SmartRF Studio


VCO (voltage controlled oscillator) tank


Inductor Q, varactor tuning range


De
-
coupling and power filtering

22

Optional components


External 455kHz ceramic IF filter


RF filter

-

LC filter (ref. data sheet)

-

SAW filter

23

Critical components


VCO inductor should be “good Q”


Murata LQN21A or Coilcraft HQ
-
series


VCO capacitors tolerance


Varactor sensitivity and Q


Crystal tolerance, drift and ageing

24

Crystal oscillator


RF frequency accuracy ~ crystal accuracy


Crystal specification:


Crystal tolerance


Crystal temperature drift (temp. range)


Crystal pulling (loading sensitivity)


Crystal load capacitance

25

Crystal load capacitance


Total capacitance seen from crystal


C151

C161

C
paracitic

26

Temperature compensation


25kHz spacing in 868MHz band require
<2.5ppm frequency accuracy


Very fine step synthesiser: 250 Hz


Crystal temperature drift compensation


External temperature sensor (single wire
chips available)


Crystal drift curve must be known


Alternative to TCXO that cost USD 3
-
5

27

VCO tank tolerances


Resonate frequency ~ component tolerance



+/
-
5% tolerance ==> 10% tuning range


Tuning voltage

Frequency

0

3

1

2

Tuning sensitivity

Tuning

range

28

VCO tuning range and sensitivity


Tuning range:


CC400: 60 MHz (14% at 433 MHz)


CC900: 75 MHz (8.6% at 869 MHz)


Tuning sensitivity:


CC400: 20 MHz/V


CC900: 25 MHz/V


Range must account for tolerances


Sensitivity influence PLL loop gain

29

VCO tank


L91 set impedance level

400MHz : 10nH, 900MHz: 3n3H


C91 set VCO gain


C92 set tuning sensitivity


C93 set absolute range



Bits C11:9 set VCO

amplifier gain, 000=max, 111=min

C91

C92

L91

VAR

C93

VCO in

V_tune from loop filter

30

IF bandwidth


60 kHz IF: 40 kHz bandwidth


200 kHz IF: 200 kHz bandwidth


455 kHz IF: Depend on ceramic filter



Signal bandwidth (Carson’s rule):


2 x frequency error (ppm)


Frequency seperation ( 2 x deviation)


2 x bitrate (Manchester code)



31

Sensitivity, data rate and IF


CC400


1.2kbps =
-
112dBm (60kHz IF, 20kHz separation)


1.2kbps =
-
107dBm (200kHz IF, 20kHz separation)


1.2kbps =
-
108dBm (455kHz external filter, 12kHz
separation)


9.6kbps =
-
105dBm (60kHz IF, 30kHz separation)


9.6kbps =
-
102dBm (200kHz IF, 30kHz separation)


9.6kbps =
-
96dBm (455kHz external filter, 20kHz
separation)

32

Sensitivity, data rate and IF


CC900


1.2kbps =
-
110dBm (60kHz IF, 20kHz separation)


1.2kbps =
-
107dBm (200kHz IF, 20kHz separation)

33

25 kHz channel operation


EN 300220: ACP <
-
37dBm


Narrow loop filter


Low data rate (1.2kbps)


Low separation / deviation (2.5
-
10kHz)


Lower output power until requirement is met


Test receiver for measurements of ACP for
correct bandwidth

34

RX precharging


Use precharging to reduce receiver turn
-
on time
(controls time
-
constant in demodulator data
slicer)


Configure CC400/CC900 to RX with
precharging


Wait for ca 5 bit periods


Configure CC400/CC900 to RX

35

RX precharging

36

Input/output match


See CC400DK user manual appendix


For CC900 the TX is not tuned (choke)


Antenna should be matched to 50 Ohm


37

SAW filter


If SAW is used in both RX and TX the output
power should not be >0dBm


Use external RX/TX switch and SAW only in RX
path

38

Increasing output power


CC900 has max 4dBm


Insert external amplifier (GaAs, SiGe)


GaAs / PIN diode switch


(insert SAW filter in receive path)

39

Layout


Place VCO in distance from input/output match
and XTAL


VCO tank with guard ring (possible to use
shield)


No hole in the ground plane (not as in
CC400DB)


Ground plane splitting depend on digital circuits
around (Most cases a hole plane is preferred)


Two layer circuit board


40

Antenna solutions


Single ended output makes it possible to use a
wide range of antennas


Antennas integrated on the PCB


stubs


loops


PCB mounted antennas


helical


ceramic, “splatch”


External antennas


helical, short or full length monopole

41

Feature
-

Benefit
-

Advantage

42

Feature
-

Benefit
-

Advantage

43

Technical support


FAE:
Peder Martin Evjen


Address:




Chipcon Components AS,


Gaustadalléen 21,



N
-
0349 OSLO, NORWAY


Phone:
+47 22 95 83 01


Fax:
+47 22 95 85 46


Web:
http://www.chipcon.com


E
-
mail:
p.m.evjen@chipcon.com