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02-17-2010

CC1101 RF modem + 250mW amplifier

Here is my home-built, cloth iron soldered, range extender for CC1101 (included onboard) RF transceiver chip from Texas Instruments. You could say that it is a CC1101+CC2591, but for 868/920MHz band. I used MAX2233 RF amplifier from Maxim-IC. It can deliver up to +24dBm (250mW) of RF amplification with +10dBm of input.

You can download the project files at the bottom of this page by clicking on red "download" button.

Schematic

CC1101 RF modem + 250mW amplifier
Click to enlarge

A few basics of CC1101 chip:

  • data transfer speed: 1.2 to 500 kbps
  • frequency: 779-928 MHz
  • output power +10dBm, without PA
  • 2-FSK, GFSK, MSK, OOK and ASK modulation schemes
  • frequency hopping ready
  • automatic address match, package protocol, CRC check

CC1101 RF modem + 250mW amplifier

After adding RF amplifier, original power of 10mW is boosted to almost 250mW or 1/4W. MAX2233 RF amp can deliver up to 250mW when powered by 3.6V, and since I used 3.3V LDO on my board, the output RF power is little less than that.

Even though all electronics on this modem work on 3.3V, everything is still compatible with 5V TTL levels which is done with a help of MAX3377 or MAX3378. The power is lowered from 5V to 3.3V by MAX8888 LDO and it can provide enough mA to supply CC1101, MAX3377/8 and the PA.

Testing

For testing I used two modems and two antennas (it figures). At the transmitting side I used monopole antenna for GSM - 900MHz, and for the receiving side I used directional yagi also for GSM - 900MHz. Details of these antennas can be found here: monopole and yagi.

Monopole antenna  Yagi antenna

In this quick test I easily achieved over 1000 meters (or 3300 feet) of range and the test-location/terrain configuration can be seen on the map: Transmitter location, and receiver location. This was achieved even without the antenna on the receiver's side! Then it started to rain and I had to go back. Oh and, I used 1.2 kbps data transfer for maximum receiver sensitivity. The data package transfered was 1 byte address and 4 bytes of payload long.

For testing I used ATmega16 and the source-code can be found in the RAR archive for download.

CC1101 RF modem + 250mW amplifier

The parts

All capacitors = eBay shop
All resistors = eBay shop
All inductors = Vishay samples
Q1 26MHz = FOX crystals samples
SMA connector = SparkFun
CC1101 RF modem = Texas Instruments samples
SN74LVC1G04 inverter = Texas Instruments samples
MAX2233 RF PA = MAXIM-IC samples
MAX8888 3v3 LDO = MAXIM-IC samples
MAX3377/MAX3378 converter = MAXIM-IC samples
HMC174MS8 = rfcandy
PCB = BatchPCB. If you need a board for this modem just use my exported gerbers and upload to BatchPCB. Do double-check them out before ordering!

Soldering of components

You would probably think that this board is impossible to solder at home. Well, I will just say that I didn't even touch my board with soldering iron or hot-air reflow iron. It was all soldered by using a solder paste and a home cloth iron. It seems that cloth iron can get hot enough (200 degrees of Celsius) to perfectly solder everything down! It sure was exhausting to place a solder-paste on every pad with a syringe needle. Instead of cloth iron you can use a hot-plate, so check this out and see how it's done.

Partlist

Exported from cc1101.brd at 02.04.2009 15:55:31
EAGLE Version 4.16r2

Part

Value

Package

     

C1

2.2u

C0603

C2

2.2u

C0603

C3

1.5n

C0603

C4

100n

C0603

C5

47n

C0603

C6

10p

C0603

C7

10p

C0603

C8

100n

C0603

C9

220p

C0603

C10

100p

C0603

C11

1p

C0603

C12

1.5p

C0603

C13

1.5p

C0603

C14

3.3p

C0603

C15

100p

C0603

C16

100p

C0603

C17

68p

C0603

C18

1.5n

C0603

C19

1uF

EIA3216

C20

100p

C0603

C21

47n

C0603

C22

0.22u

C0603

C23

100p

C0603

C24

3.9p

C0603

C25

47n

C0603

C26

47n

C0603

C27

100p

C0603

C28

100p

C0603

IC1

CC1101

QLP-20-NEW

IC3

MAX3377/
MAX3378
TSSOP14

MAX3377

IC5

MAX8888_3v3

SOT23-5

JP1

M09

1X09

L1

12nH

0603

L2

12nH

0603

L3

18nH

0603

L4

18nH

0603

L5

12nH

0603

L6

12nH

0603

L7

15nH

0603

L8

27nH

0603

L9

2.55nH

0603

Q1

26MHz

CRYSTAL-SMD-5X3

R1

56k

R0603

SMA1

SMA_EDGE

SMA-EDGE

SN74LVC1G04 1G04

SOT23-5

U$1

MAX2233

TSSOP16

U2

HMC174MS8

MSOP8

U3

HMC174MS8

MSOP8

elektronika.ba

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