PRODUCT SPECIFICATION
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 1 of 36 June 2004
Single chip 433/868/915 MHz Transceiver nRF905
FEATURES APPLICATIONS
• True single chip GFSK transceiver in a small
32-pin package (32L QFN 5x5mm)
• ShockBurst™ mode for low power operation
• Power supply range 1.9 to 3.6 V
• Multi channel operation – ETSI/FCC
Compatible
• Channel switching time <650µs
• Extremely low cost Bill of Material (BOM)
• No external SAW filter
• Adjustable output power up to 10dBm
• Carrier detect for "listen before transmit"
protocols
• Data Ready signal when a valid data package
is received or transmitted
• Address Match for detection of incoming
package
• Automatic retransmission of data packages
• Automatic CRC and preamble generation
• Low supply current (TX), typical 11mA
@ -10dBm output power
• Low supply current (RX), typical 12.5mA
• Wireless data communication
• Alarm and security systems
• Home Automation
• Remote control
• Surveillance
• Automotive
• Telemetry
• Industrial sensors
• Keyless entry
• Toys
GENERAL DESCRIPTION
nRF905 is a single-chip radio transceiver for the 433/868/915 MHz ISM band. The
transceiver consists of a fully integrated frequency synthesiser, receiver chain with
demodulator, a power amplifier, a crystal oscillator and a modulator. The
ShockBurstTM feature automatically handles preamble and CRC. Configuration is
easily programmable by use of the SPI interface. Current consumption is very low, in
transmit only 11mA at an output power of -10dBm, and in receive mode 12.5mA.
Built in power down modes makes power saving easily realizable.
QUICK REFERENCE DATA
Parameter Value Unit
Minimum supply voltage 1.9 V
Maximum transmit output power 10 dBm
Transmitted data rate (Manchester-encoder embedded) 100 kbps
Supply current in transmit @ -10dBm output power 11 mA
Supply current in receive mode 12.5 mA
Temperature range -40 to +85 °C
Typical Sensitivity -100 dBm
Supply current in power down mode 2.5 µΑ
Table 1 nRF905 quick reference data.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 2 of 36 June 2004
ORDERING INFORMATION
Type Number Description Version
nRF905 IC 32L QFN 5x5mm -
nRF905-EVKIT 433 Evaluation kit 433MHz 1.0
nRF905-EVKIT 868/915 Evaluation kit 868/915MHz 1.0
Table 2 nRF905 ordering information.
BLOCK DIAGRAM
SPI
interface
ShockBurst
Demod
Dataslicer
Address
decode
CRC code/
decode
GFSK
filter
RX - reg.
Config-reg.
TX - reg.
TX - addr.
PA
LNA
IF BBF
Frequency
Synthesiser
Voltage
regulators Crystal
oscillator
MOSI (11)
MISO (10)
SCK (12)
CSN (13)
TRX_CE (1)
PWR_UP (2)
TX_EN (32)
CD (6)
AM (7)
DR (8)
uPCLK (3)
XC1 (14)
XC2 (15)
ANT1 (20)
ANT2 (21)
VDD_PA (19)
VSS (5)
VSS (16)
VSS (18)
VSS (21)
VSS (24)
VSS (27)
VSS (28)
VSS (29)
VSS (30)
VDD (4)
VDD (17)
VDD (25)
DVDD_1V2 (31)
IREF (23)
Manchester
encoder/
decoder
VSS (26)
VSS (9)
Figure 1 nRF905 with external components.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 3 of 36 June 2004
PIN FUNCTIONS
Pin Name Pin function Description
1TRX_CE Digital input Enables chip for receive and transmit
2PWR_UP Digital input Power up chip
3uPCLK Clock output Output clock, divided crystal oscillator full-swing clock
4VDD Power Power supply (+3V DC)
5VSS Power Ground (0V)
6CD Digital output Carrier Detect
7AM Digital output Address Match
8DR Digital output Receive and transmit Data Ready
9VSS Power Ground (0V)
10 MISO SPI - interface SPI output
11 MOSI SPI - interface SPI input
12 SCK SPI - Clock SPI clock
13 CSN SPI - enable SPI enable, active low
14 XC1 Analog Input Crystal pin 1/ External clock reference pin
15 XC2 Analog Output Crystal pin 2
16 VSS Power Ground (0V)
17 VDD Power Power supply (+3V DC)
18 VSS Power Ground
19 VDD_PA Power output Positive supply (1.8V) to nRF905 power amplifier
20 ANT1 RF Antenna interface 1
21 ANT2 RF Antenna interface 2
22 VSS Power Ground (0V)
23 IREF Analog Input Reference current
24 VSS Power Ground (0V)
25 VDD Power Power supply (+3V DC)
26 VSS Power Ground (0V)
27 VSS Power Ground (0V)
28 VSS Power Ground (0V)
29 VSS Power Ground (0V)
30 VSS Power Ground (0V)
31 DVDD_1V2 Power Low voltage positive digital supply output for de-coupling
32 TX_EN Digital input TX_EN=”1”TX mode, TX_EN=”0”RX mode
Table 3 nRF905 pin function.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 4 of 36 June 2004
PIN ASSIGNMENT
nRF905
32L QFN 5x5
MOSI
VSS
CD
DVDD_1V2
AM
XC2 VSS
DR
VSS
ANT2
VDD_PA
VSS
ANT1
VSS
VSS VDD
VSS
TRX_CE
XC1
4
3
2
1
6
5
7
8
9 13 1412 1510 11 16
24
23
22
20
19
21
18
17
29 28 2730 26 25
31
32
VDD
VSSTX_EN
IREF
VSS VSS VSS
MISO
PWR_UP
uPCLK
VDD
CSNSCK
Figure 2 nRF905 pin assignment (top view) for a 32L QFN 5x5 package.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 5 of 36 June 2004
ELECTRICAL SPECIFICATIONS
Symbol Parameter (condition) Notes Min. Typ. Max. Units
Operating conditions
VDD Supply voltage 1.9 3.0 3.6 V
TEMP Operating temperature -40 27 85 ºC
Digital input pin
VIH HIGH level input voltage VDD-0.3 VDD V
VIL LOW level input voltage VSS 0.3 V
Digital output pin
VOH HIGH level output voltage (IOH=-0.5mA) VDD-0.3 VDD V
VOL LOW level output voltage (IOL=0.5mA) VSS 0.3 V
General electrical specification
Istby_eclk Supply current in standby, uCLK enabled 1) 100 µA
Istby_dclk Supply current in standby, uCLK disabled 2) 12.5 µA
IPD Supply current in power down mode 2.5 µA
ISPI Supply current in SPI programming 3) 20 µA
General RF conditions
fOP Operating frequency 4) 430 928 MHz
fXTAL Crystal frequency 5) 4 20 MHz
∆fFrequency deviation ±42 ±50 ±58 kHz
RGFSK GFSK data rate, Manchester-encoded 100 kbps
fCH433 Channel spacing for 433MHz band 100 kHz
fCH868/915 Channel spacing for 868/915MHz band 200 kHz
Transmitter operation
PRF10 Output power 10dBm setting 6) 7 10 11 dBm
PRF6 Output power 6dBm setting 6) 3 6 9 dBm
PRF-2 Output power –2dBm setting 6) -6 -2 2dBm
PRF-10 Output power -10dBm setting 6) -14 -10 -6 dBm
PBW 20dB bandwidth for modulated carrier 190 kHz
PRF1 1st adjacent channel transmit power 7) -27 dBc
PRF2 2nd adjacent channel transmit power 7) -54 dBc
ITX10dBm Supply current @ 10dBm output power 30 mA
ITX-10dBm Supply current @ -10dBm output power 11 mA
Receiver operation
IRX Supply current in receive mode 12.5 mA
RXSENS Sensitivity at 0.1%BER -100 dBm
RXMAX Maximum received signal 0dBm
C/ICO C/I Co-channel 8) 13 dB
C/I1ST 1st adjacent channel selectivity C/I 200kHz 8) -7 dB
C/I2ND 2nd adjacent channel selectivity C/I 400kHz 8) -16 dB
C/IIM Image rejection 8) -30 dB
Table 4 nRF905 electrical specifications.
1) Output frequency is 4MHz load of external clock pin is 5pF, Crystal is 4MHz.
2) Crystal is 4MHz.
3) Chip in power down, SPI_SCK frequency is 1MHz.
4) Operates in the 433, 868 and 915 MHz ISM band.
5) The crystal frequency may be chosen from 5 different values (4, 8, 12, 16, and 20MHz)
6) Optimum load impedance, please see peripheral RF information.
7) Channel width and channel spacing is 200kHz.
8) Channel Level +3dB over sensitivity, interfering signal a standard CW, image lies 2MHz above wanted.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 6 of 36 June 2004
CURRENT CONSUMPTION
MODE CRYSTAL
FREQ. [MHZ] OUTPUT
CLOCK
FREQ. [MHZ]
TYPICAL
CURRENT
Power Down 16 OFF 2.5 uA
Standby 4OFF 12 uA
Standby 8OFF 25 uA
Standby 12 OFF 27 uA
Standby 16 OFF 32 uA
Standby 20 OFF 46 uA
Standby 40.5 110 uA
Standby 80.5 125 uA
Standby 12 0.5 130 uA
Standby 16 0.5 135 uA
Standby 20 0.5 150 uA
Standby 4 1 130 uA
Standby 8 1 145 uA
Standby 12 1150 uA
Standby 16 1155 uA
Standby 20 1170 uA
Standby 4 2 170 uA
Standby 8 2 185 uA
Standby 12 2190 uA
Standby 16 2195 uA
Standby 20 2210 uA
Standby 4 4 260 uA
Standby 8 4 275 uA
Standby 12 4280 uA
Standby 16 4285 uA
Standby 20 4300 uA
Rx @ 433 16 OFF 12.2 mA
Rx @ 868/915 16 OFF 12.8 mA
Reduced Rx 16 OFF 10.5 mA
Tx @ 10dBm 16 OFF 30 mA
Tx @ 6dBm 16 OFF 20 mA
Tx @ -2dBm 16 OFF 14 mA
Tx @ -10dBm 16 OFF 11 mA
Conditions: VDD = 3.0V, VSS = 0V, TA = 27ºC,
Load capacitance of external clock = 13pF, Crystal load capacitance = 12pF
Table 5 nRF905 current consumption.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 7 of 36 June 2004
PACKAGE OUTLINE
nRF905 uses the QFN 32L 5x5 green package with a mat tin finish. Dimensions are in
mm. Recommended soldering reflow profile can be found in application note
nAN400-08, QFN soldering reflow guidelines, www.nordicsemi.no.
+
Package Type A A1A2 bDEeJKL
QFN32
(5x5 mm) Min
typ.
Max
0.8
0.9
0.0
0.05
0.65
0.69
0.18
0.23
0.3 5 BSC 5 BSC 0.5 BSC 3.2
3.3
3.4
3.2
3.3
3.4
0.3
0.4
0.5
Figure 3 nRF905 package outline.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 8 of 36 June 2004
ABSOLUTE MAXIMUM RATINGS
Supply Voltages
VDD...............................- 0.3V to + 3.6V
VSS .....................................................0V
Input Voltage
VI..........................- 0.3V to VDD + 0.3V
Output Voltage
VO.........................- 0.3V to VDD + 0.3V
Total Power Dissipation
PD (TA=85°C)................................ 200mW
Temperatures
Operating temperature............................................ - 40°C to + 85°C
Storage temperature...............................................- 40°C to + 125°C
Note: Stress exceeding one or more of the limiting values may cause permanent
damage to the device.
ATTENTION!
Electrostatic sensitive device.
Observe precaution for handling.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 9 of 36 June 2004
GLOSSARY OF TERMS
Term Description
ADC Analog to Digital Converter
AM Address Match
CD Carrier Detect
CLK Clock
CRC Cyclic Redundancy Check
DR Data Ready
GFSK Gaussian Frequency Shift Keying
ISM Industrial-Scientific-Medical
kSPS kilo Samples per Second
MCU Micro Controller Unit
PWR_DWN Power Down
PWR_UP Power Up
RX Receive
SPI Serial Programmable Interface
CSN SPI Chip Select Not
MISO SPI Master In Slave Out
MOSI SPI Master Out Slave In
SCK SPI Serial Clock
SPS Samples per Second
STBY Standby
TRX_EN Transmit/Receive Enable
TX Transmit
TX_EN Transmit Enable
Table 6 Glossary of terms.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 10 of 36 June 2004
MODES OF OPERATION
The nRF905 has two active (RX/TX) modes and two power-saving modes
Active Modes• ShockBurst™ RX
• ShockBurst™ TX
Power Saving Modes
• Power down and SPI - programming
• Standby and SPI - programming
The nRF905 mode is decided by the settings of TRX_CE, TX_EN and PWR_UP.
PWR_UP TRX_CE TX_EN Operating Mode
0X X Power down and SPI – programming
1 0 XStandby and SPI – programming
1X0Read data from RX register
1 1 0 Radio Enabled - ShockBurstTM RX
1 1 1 Radio Enabled - ShockBurstTM TX
Table 7 nRF905 operational modes.
nRF ShockBurst™ Mode
The nRF905 uses the Nordic Semiconductor ASA ShockBurst™ feature.
ShockBurstTM makes it possible to use the high data rate offered by the nRF905
without the need of a costly, high-speed micro controller (MCU) for data
processing/clock recovery. By placing all high speed signal processing related to RF
protocol on-chip, the nRF905 offers the application micro controller a simple SPI
interface, the data rate is decided by the interface-speed the micro controller itself sets
up. By allowing the digital part of the application to run at low speed, while
maximizing the data rate on the RF link, the nRF905 ShockBurst™ mode reduces the
average current consumption in applications. In ShockBurstTM RX, Address Match
(AM) and Data Ready (DR) notifies the MCU when a valid address and payload is
received respectively. In ShockBurstTM TX, the nRF905 automatically generates
preamble and CRC. Data Ready (DR) notifies the MCU that the transmission is
completed. All together, this means reduced memory demand in the MCU resulting in
a low cost MCU, as well as reduced software development time.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 11 of 36 June 2004
Typical ShockBurstTM TX:
1. When the application MCU has data for a remote node, the address of the
receiving node (TX-address) and payload data (TX-payload) are clocked
into nRF905 via the SPI interface. The application protocol or MCU sets
the speed of the interface.
2. MCU sets TRX_CE and TX_EN high, this activates a nRF905
ShockBurst™ transmission.
3. nRF905 ShockBurst™:
• Radio is automatically powered up.
• Data package is completed (preamble added, CRC calculated).
• Data package is transmitted (100kbps, GFSK, Manchester-encoded).
• Data Ready is set high when transmission is completed.
4. If AUTO_RETRAN is set high, the nRF905 continuously retransmits the
package until TRX_CE is set low.
5. When TRX_CE is set low, the nRF905 finishes transmitting the outgoing
package and then sets itself into standby mode.
The ShockBurstTM mode ensures that a transmitted package that has started always
finishes regardless of what TRX_EN and TX_EN is set to during transmission. The
new mode is activated when the transmission is completed. Please see subsequent
chapters for detailed timing
For test purposes such as antenna tuning and measuring output power it is possible to
set the transmitter so that a constant carrier is produced. To do this TRX_CE must be
maintained high instead of being pulsed. In addition Auto Retransmit should be
switched off. After the burst of data has been sent then the device will continue to
send the unmodulated carrier.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 12 of 36 June 2004
SPI - programming
uController loading ADDR
and PAYLOAD data
(Configuration register if
changes since last TX/RX)
NO
YES
nRF ShockBurst TX
Generate CRC and preamble
Sending package
DR is set high when completed
Transmitter
is powered
up
TRX_CE
= HI ?
AUTO_
RETRAN
= HI ?
YES
NO
YES
NO
ADDR PAYLOAD
Data Package
Bit in configuration
register
TRX_CE
= HI ?
Radio in Standby
TX_EN = HI
PWR_UP = HI
TRX_CE = LO
ADDR PAYLOAD CRC
Pre-
amble
DR is
set low
after pre-
amble
Figure 4 Flowchart ShockBurstTM transmit of nRF905.
NB: DR is set low under the following conditions after it has been set high:
• If TX_EN is set low
• If PWR_UP is set low
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 13 of 36 June 2004
Typical ShockBurstTM RX:
1. ShockBurstTM RX is selected by setting TRX_CE high and TX_EN low.
2. After 650µs nRF905 is monitoring the air for incoming communication.
3. When the nRF905 senses a carrier at the receiving frequency, Carrier
Detect (CD) pin is set high.
4. When a valid address is received, Address Match (AM) pin is set high.
5. When a valid package has been received (correct CRC found), nRF905
removes the preamble, address and CRC bits, and the Data Ready (DR)
pin is set high.
6. MCU sets the TRX_CE low to enter standby mode (low current mode).
7. MCU can clock out the payload data at a suitable rate via the SPI interface.
8. When all payload data is retrieved, nRF905 sets Data Ready (DR) and
Address Match (AM) low again.
9. The chip is now ready for entering ShockBurstTM RX, ShockBurstTM TX or
power down mode.
If TRX_CE or TX_EN is changed during an incoming package, the nRF905 changes
mode immediately and the package is lost. However, if the MCU is sensing the
Address Match (AM) pin, it knows when the chip is receiving an incoming package
and can therefore decide whether to wait for the Data Ready (DR) signal or enter a
different mode.
To avoid spurious address matches it is recommended that the address length be 24
bits or higher in length. Small addresses such as 8 or 16 bits can often lead to
statistical failures due to the address being repeated as part of the data packet. This
can be avoided by using a longer address.
Each byte within the address should be unique. Repeating bytes within the address
reduces the effectiveness of the address and increases its susceptibility to noise hence
increasing the packet error rate. The address should also have several level shifts (i.e.
10101100) to reduce the statistical effect of noise and hence reduce the packet error
rate.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 14 of 36 June 2004
Figure 5 Flowchart ShockBurstTM receive of nRF905.
NO
YES
Receiver is
powered up
NO
YES
Receiving
data
Receiver
Sensing for incomming data
CD is set high if carrier
AM is set
high
NO
DR high is
set high
Radio enters
STBY
MCU clocks out payload via
the SPI interface
DR and AM are
set low
YES
YES
NO
AM is set low
Radio in Standby
TX_EN = LO
PWR_UP = HI
TRX_CE
= HI ?
Correct
ADDR?
Correct
CRC?
TRX_CE
= HI ?
PAYLOAD
Data Package
ADDR PAYLOAD CRC
Pre-
amble
RX Remains
On
MCU clocks out payload via
the SPI interface
DR and AM are
set low
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 15 of 36 June 2004
Power Down Mode
In power down the nRF905 is disabled with minimal current consumption, typically
less than 2.5µA. When entering this mode the device is not active which will
minimize average current consumption and maximizing battery lifetime. The
configuration word content is maintained during power down.
Standby Mode
Standby mode is used to minimize average current consumption while maintaining
short start up times to ShockBurstTM RX and ShockBurstTM TX. In this mode part of
the crystal oscillator is active. Current consumption is dependent on crystal frequency,
Ex: IDD= 12µA @4MHz and IDD =46µA @20MHz. If the uP-clock (pin 3) of nRF905
is enabled, current consumption increases and is dependent on the load capacitance
and frequency. The configuration word content is maintained during standby.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 16 of 36 June 2004
DEVICE CONFIGURATION
All configuration of the nRF905 is via the SPI interface. The interface consists of five
registers; a SPI instruction set is used to decide which operation shall be performed.
The SPI interface can be activated in any mode however Nordic Semiconductor ASA
recommends the chip be in standby or power down mode.
SPI Register Configuration
The SPI interface consists of five internal registers. A register read-back mode is
implemented to allow verification of the register contents.
TX-PAYLOAD
EN
DTA
CLK
I/O-reg
CSN
MOSI
MISO
SCK
RF - CONFIGURATION
REGISTER
EN
DTA
CLK
TX-ADDRESS
EN
DTA
CLK
RX-PAYLOAD
EN
DTA
CLK
STATUS-REGISTER
EN
DTA
CLK
Figure 6 SPI – interface and the five internal registers.
Status – Register
Register contains status of Data Ready (DR) and Address Match (AM).
RF - Configuration Register
Register contains transceiver setup information such as frequency and output power
ext.
TX – Address
Register contains address of target device. How many bytes used is set in the
configuration register.
TX – Payload
Register containing the payload information to be sent in a ShockBurst TM package.
How many bytes used is set in the configuration register.
RX – Payload
Register containing the payload information derived from a received valid ShockBurst
TM package. How many bytes used is set in the configuration register. Valid data in
the RX-Payload register is indicated with a high Date Ready (DR) signal.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 17 of 36 June 2004
SPI Instruction Set
The available commands to be used on the SPI interface is shown below. Whenever
CSN is set low the interface expects an instruction. Every new instruction must be
started by a high to low transition on CSN.
Instruction set for the nRF905 SPI Serial Interface
Instruction Name Instruction
Format Operation
W_CONFIG
(WC) 0000 AAAA Write Configuration-register. AAAA indicates which byte
the write operation is to be started from. Number of bytes
depends on start address AAAA.
R_CONFIG
(RC) 0001 AAAA Read Configuration-register. AAAA indicates which byte
the read operation is to be started from. Number of bytes
depends on start address AAAA.
W_TX_PAYLOAD
(WTP) 0010 0000 Write TX-payload: 1 – 32 bytes. A write operation will
always start at byte 0.
R_TX_PAYLOAD
(RTP) 0010 0001 Read TX-payload: 1 – 32 bytes. A read operation will
always start at byte 0.
W_TX_ADDRESS
(WTA) 0010 0010 Write TX-address: 1 – 4 bytes. A write operation will
always start at byte 0.
R_TX_ADDRESS
(RTA) 0010 0011 Read TX-address: 1 – 4 bytes. A read operation will
always start at byte 0
R_RX_PAYLOAD
(RRP) 0010 0100 Read RX-payload: 1 – 32 bytes. A read operation will
always start at byte 0.
CHANNEL_CONFIG
(CC) 1000 pphc
cccc cccc Special command for fast setting of CH_NO,
HFREQ_PLL and PA_PWR in the CONFIGURATION
REGISTER. CH_NO= ccccccccc, HFREQ_PLL = h
PA_PWR = pp
Table 8 Instruction set for the nRF905 SPI interface.
A read or a write operation may operate on a single byte or on a set of succeeding
bytes from a given start address defined by the instruction. When accessing
succeeding bytes one will read or write MSB of the byte with the smallest byte
number first. The content of the status-register will always be read to MISO after a
high to low transition on CSN.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 18 of 36 June 2004
SPI Timing
Data is clocked into or out of the device on the rising edge of the clock pulse. The
clock speed is determined by the MCU and may be from 1Hz to 10MHz depending on
the MCU. The device must be in one of the power saving modes for the configuration
registers to be read or written to.
CSN
SCK
MOSI
MISO
0 1 2 3 7 8 15
Command 8 bits, MSB = C7
C
7C
6C
5C
4C
3C
2C
1C
0
Status byte as output, MSB = S7 Addressed byte as output, MSB = O7
Succeeding bytes to addressed byte
as output
S
7S
6S
5S
4S
3S
2S
1S
0O
7O
6O
5O
4O
3O
2O
1O
0
Figure 7 SPI read operation.
CSN
SCK
MOSI
MISO
0 1 2 3 7 8 15
Command 8 bits, MSB = C7
C
7C
6C
5C
4C
3C
2C
1C
0
Status byte as output, MSB = S7
S
7S
6S
5S
4S
3S
2S
1S
0
D
7D
6D
5D
4D
3D
2D
1D
0
First data byte as input, MSB = D7
Succeeding data bytes as input
Figure 8 SPI write operation.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 19 of 36 June 2004
RF - Configuration – Register Description
Parameter Bitwidth Description
CH_NO 9Sets center freq. together with HFREQ_PLL (default = 001101100b = 108d).
fRF = ( 422.4 + CH_NOd /10)*(1+HFREQ_PLLd) MHz
HFREQ_
PLL 1Sets PLL in 433 or 868/915 MHz mode (default = 0).
'0' – Chip operating in 433MHz band
'1' – Chip operating in 868 or 915 MHz band
PA_PWR 2Output power (default = 00).
'00' -10dBm
'01' -2dBm
'10' +6dBm
'11' +10dBm
RX_RED_
PWR 1Reduces current in RX mode by 1.6mA. Sensitivity is reduced (default = 0).
'0' – Normal operation
'1' – Reduced power
AUTO_
RETRAN 1Retransmit contents in TX register if TRX_CE and TXEN are high (default = 0).
'0' – No retransmission
'1' – Retransmission of data package
RX_AFW 3RX-address width (default = 100).
'001' – 1 byte RX address field width
'100' – 4 byte RX address field width
TX_AFW 3TX-address width (default = 100).
'001' – 1 byte TX address field width
'100' – 4 byte TX address field width
RX_PW 6RX-payload width (default = 100000).
'000001' – 1 byte RX payload field width
'000010' – 2 byte RX payload field width
.
'100000' – 32 byte RX payload field width
TX_PW 6TX-payload width (default = 100000).
'000001' – 1 byte TX payload field width
'000010' – 2 byte TX payload field width
.
'100000' – 32 byte TX payload field width
RX_
ADDRESS 32 RX address identity. Used bytes depend on RX_AFW (default = E7E7E7E7h).
UP_CLK_
FREQ 2Output clock frequency (default = 11).
'00' – 4MHz
'01' – 2MHz
'10' – 1MHz
'11' – 500kHz
UP_CLK_
EN 1Output clock enable (default = 1).
'0' – No external clock signal available
'1' – External clock signal enabled
XOF 3Crystal oscillator frequency. Must be set according to external crystal resonant-
frequency (default = 100).
'000' – 4MHz
'001' – 8MHz
'010' – 12MHz
'011' – 16MHz
'100' – 20MHz
CRC_EN 1CRC – check enable (default = 1).
'0' – Disable
'1' – Enable
CRC_
MODE 1CRC – mode (default = 1).
'0' – 8 CRC check bit
'1' – 16 CRC check bit
Table 9 Configuration-register description.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 20 of 36 June 2004
Register Contents
RF-CONFIG_REGISTER (R/W)
Byte # Content bit[7:0], MSB = bit[7] Init value
0CH_NO[7:0] 0110_1100
1bit[7:6] not used, AUTO_RETRAN, RX_RED_PWR, PA_PWR[1:0],
HFREQ_PLL, CH_NO[8] 0000_0000
2bit[7] not used, TX_AFW[2:0] , bit[3] not used, RX_AFW[2:0] 0100_0100
3bit[7:6] not used, RX_PW[5:0] 0010_0000
4bit[7:6] not used, TX_PW[5:0] 0010_0000
5RX_ADDRESS (device identity) byte 0 E7
6RX_ADDRESS (device identity) byte 1 E7
7RX_ADDRESS (device identity) byte 2 E7
8RX_ADDRESS (device identity) byte 3 E7
9CRC_MODE,CRC_EN, XOF[2:0], UP_CLK_EN, UP_CLK_FREQ[1:0] 1110_0111
TX_PAYLOAD (R/W)
Byte # Content bit[7:0], MSB = bit[7] Init value
0TX_PAYLOAD[7:0] X
1TX_PAYLOAD[15:8] X
- - X
- - X
30 TX_PAYLOAD[247:240] X
31 TX_PAYLOAD[255:248] X
TX_ADDRESS (R/W)
Byte # Content bit[7:0], MSB = bit[7] Init value
0TX_ADDRESS[7:0] E7
1TX_ADDRESS[15:8] E7
2TX_ADDRESS[23:16] E7
3TX_ADDRESS[31:24] E7
RX_PAYLOAD (R)
Byte # Content bit[7:0], MSB = bit[7] Init value
0RX_PAYLOAD[7:0] X
1RX_PAYLOAD[15:8] X
-X
-X
30 RX_PAYLOAD[247:240] X
31 RX_PAYLOAD[255:248] X
STATUS_REGISTER (R)
Byte # Content bit[7:0], MSB = bit[7] Init value
0AM, bit [6] not used, DR, bit [0:4] not used X
Table 10 RF register contents.
The length of all registers is fixed. However, the bytes in TX_PAYLOAD,
RX_PAYLOAD, TX_ADDRESS and RX_ADDRESS used in ShockBurst TM RX/TX
are set in the configuration register. Register content is not lost when the device enters
one of the power saving modes.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 21 of 36 June 2004
IMPORTANT TIMING DATA
The following timing must be obeyed during nRF905 operation.
Device Switching Times
nRF905 timing Max.
PWR_DWN è ST_BY mode 3 ms
STBY è TX Shock Burst™ 650 µs
STBY è RX Shock Burst™ 650 µs
RX Shock Burst™ è TX Shock Burst™ 550 1µs
TX Shock Burst™ è RX Shock Burst™ 550 1µs
Notes to table:
1) RX to TX or TX to RX switching is available without re-programming of the RF
configuration register. The same frequency channel is maintained.
Table 11 Switching times for nRF905.
ShockBurstTM TX timing
MOSI
CSN
PWR_UP
TX_EN
TRX_CE
TX DATA
TIME
T0 = Radio Enabled
T1 = T0+10uS Minimum TRX_CE pulse
T2 = T0 + 650uS.Start of TX Data transmission
T3 = End of Data Packet, enter Standby mode
Programming of
Configuration Register
and TX Data Register
T0 T1 T2 T3
Transmitted Data 100kbps
Manchester Encoded
Figure 9 Timing diagram for standby to transmit.
After a data packet has finished transmitting the device will automatically enter
Standby mode and wait for the next pulse of TRX_CE. If the Auto Re-Transmit
function is enabled the data packet will continue re-sending the same data packet until
TRX_CE is set low.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 22 of 36 June 2004
ShockBurstTM RX timing
PWR_UP
TX_EN
TRX_CE
RX DATA
TIME
AM
DR
CD
T0 = Receiver Enabled -Listening for Data
T1 = Carrier Detect finds a carrier
T2 = AM - Correct Address Found
T3 = DR - Data packet with correct Address/CRC
650uS to enter RX
mode from
TRX_CE being set
high.
T0 T1 T2 T3
650uS
Figure 10 Timing diagram for standby to receiving.
After the Data Ready (DR) has been set high a valid data packet is available in the RX
data register. This may be clocked out in RX mode or standby mode. After the data
has been clocked out via the SPI interface the Data Ready (DR) and Address Match
(AM) pins are reset to low.
The RX register is reset if the PWR_UP pin is taken low or if the device is switched
into TX mode i.e. TXEN is taken high. This will also results in the Data Ready(DR)
and Address Match (AM) pins being reset to low.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 23 of 36 June 2004
PERIPHERAL RF INFORMATION
Crystal Specification
Tolerance includes initially accuracy and tolerance over temperature and aging.
Frequency CLESR C0max Tolerance @
868/915 MHz Tolerance @
433 MHz
4MHz 12pF 150Ω7.0pF ±30ppm ±60ppm
8MHz 12pF 100Ω7.0pF ±30ppm ±60ppm
12MHz 12pF 100Ω7.0pF ±30ppm ±60ppm
16MHz 12pF 100Ω7.0pF ±30ppm ±60ppm
20MHz 12pF 100Ω7.0pF ±30ppm ±60ppm
Table 12 Crystal specification of nRF905.
To achieve a crystal oscillator solution with low power consumption and fast start-up
time, it is recommended to specify the crystal with a low value of crystal load
capacitance. Specifying CL =12pF is acceptable, but it is possible to use up to 16pF.
Specifying a lower value of crystal parallel equivalent capacitance, Co=1.5pF is also
good, but this can increase the price of the crystal itself. Typically Co=1.5pF at a
crystal specified for Co_max=7.0pF.
External Clock Reference
An external reference clock, such as a MCU clock, may be used instead of a crystal.
The clock signal should be applied directly to the XC1 pin, the XC2 pin can be left
high impedance. When operating with an external clock instead of a crystal the clock
must be applied in standby mode to achieve low current consumption. If the device is
set into standby mode with no external clock or crystal then the current consumption
will increase up to a maximum of 1mA.
Microprocessor Output Clock
By default a microprocessor clock output is provided. Providing an output clock will
increase the current consumption in standby mode. The current consumption in
standby will depend on frequency and load of external crystal, frequency of output
clock and capacitive load of the provided output clock. Typical current consumption
values are found in Table 5
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 24 of 36 June 2004
Antenna Output
The “ANT1 & ANT2” output pins provide a balanced RF output to the antenna. The
pins must have a DC path to VDD_PA, either via a RF choke or via the center point
in a dipole antenna. The load impedance seen between the ANT1/ANT2 outputs
should be in the range 200-700Ω. The optimum differential load impedance at the
antenna ports is given as:
900MHz 225Ω+j210
430MHz 300Ω+j100
A low load impedance (for instance 50Ω) can be obtained by fitting a simple
matching network or a RF transformer (balun). Further information regarding balun
structures and matching networks may be found in the Application Examples chapter.
Output Power Adjustment
The power amplifier in nRF905 can be programmed to four different output power
settings by the configuration register. By reducing output power, the total TX current
is reduced.
Power setting RF output power DC current consumption
00 -10 dBm 11.0 mA
01 -2 dBm 14.0 mA
10 6 dBm 20.0 mA
11 10 dBm 30.0 mA
Conditions: VDD = 3.0V, VSS = 0V, TA = 27ºC, Load impedance = 400 Ω.
Table 13 RF output power setting for the nRF905.
Modulation
The modulation of nRF905 is Gaussian Frequency Shift Keying (GFSK) with a data-
rate of 100kbps. Deviation is ±50kHz. GFSK modulation results in a more bandwidth
effective transmission-link compared with ordinary FSK modulation.
The data is internally Manchester encoded (TX) and Manchester decoded (RX). That
is, the effective symbol-rate of the link is 50kbps. By using internally Manchester
encoding, no scrambling in the u-controller is needed.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 25 of 36 June 2004
Output Frequency
The operating RF-frequency of nRF905 is set in the configuration register by CH_NO
and HFREQ_PLL. The operating frequency is given by:
MHzPLLHFREQNOCHfOP )_1())10/_(4.422(+⋅+=
When HFREQ_PLL is ‘0’ the frequency resolution is 100kHz and when it is ‘1’ the
resolution is 200kHz.
The application operating frequency has to be chosen to apply with the Short Range
Devise regulation in the area of operation.
Operating frequency HFREQ_PLL CH_NO
430.0 MHz [0] [001001100]
433.1 MHz [0] [001101011]
433.2 MHz [0] [001101100]
434.7 MHz [0] [001111011]
862.0 MHz [1] [001010110]
868.2 MHz [1] [001110101]
868.4 MHz [1] [001110110]
869.8 MHz [1] [001111101]
902.2 MHz [1] [100011111]
902.4 MHz [1] [100100000]
927.8 MHz [1] [110011111]
Table 14 Examples of real operating frequencies.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 26 of 36 June 2004
PCB Layout and Decoupling Guidelines
nRF905 is an extremely robust RF device due to internal voltage regulators and
requires the minimum of RF layout protocols. However the following design rules
should still be incorporated into the layout design.
A PCB with a minimum of two layers including a ground plane is recommended for
optimum performance. The nRF905 DC supply voltage should be decoupled as close
as possible to the VDD pins with high performance RF capacitors. It is preferable to
mount a large surface mount capacitor (e.g. 4.7µF tantalum) in parallel with the
smaller value capacitors. The nRF905 supply voltage should be filtered and routed
separately from the supply voltages of any digital circuitry.
Long power supply lines on the PCB should be avoided. All device grounds, VDD
connections and VDD bypass capacitors must be connected as close as possible to the
nRF905 IC. For a PCB with a topside RF ground plane, the VSS pins should be
connected directly to the ground plane. For a PCB with a bottom ground plane, the
best technique is to place via holes as close as possible to the VSS pins. A minimum
of one via hole should be used for each VSS pin.
Full swing digital data or control signals should not be routed close to the crystal or
the power supply lines.
A fully qualified RF-layout for the nRF905 and its surrounding components,
including antennas and matching networks, can be downloaded from
www.nordicsemi.no.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 27 of 36 June 2004
nRF905 FEATURES
Carrier Detect.
When the nRF905 is in ShockBurst TM RX, the Carrier Detect (CD) pin is set high if a
RF carrier is present at the channel the device is programmed to. This feature is very
effective to avoid collision of packages from different transmitters operating at the
same frequency. Whenever a device is ready to transmit it could first be set into
receive mode and sense whether or not the wanted channel is available for outgoing
data. This forms a very simple listen before transmit protocol. Operating Carrier
Detect (CD) with Reduced RX Power mode is an extremely power efficient RF
system. Typical Carrier Detect level (CD) is typically 5dB lower than sensitivity, i.e.
if sensitivity is –100dBm then the Carrier Detect function will sense a carrier wave as
low as –105dBm. Below –105dBm the Carrier Detect signal will be low, i.e. 0V.
Above –95dBm the Carrier Detect signal will be high, i.e. Vdd. Between
approximately -95 to -105 the Carrier Detect Signal will toggle.
Address Match
When the nRF905 is in ShockBurst TM RX mode, the Address Match (AM) pin is set
high as soon as an incoming package with an address that is identical with the
device’s own identity is received. With the Address Match pin the controller is alerted
that the nRF905 is receiving data actually before the Data Ready (DR) signal is set
high. If the Data Ready (DR) pin is not set high i.e. the CRC is incorrect then the
Address Match (AM) pin is reset to low at the end of the received data packet. This
function can be very useful for an MCU. If Address Match (AM) is high then the
MCU can make a decision to wait and see if Data Ready (DR) will be set high
indicating a valid data package has been received or ignore that a possible package is
being received and switch modes.
Data Ready
The Data Ready (DR) signal makes it possible to largely reduce the complexity of the
MCU software program.
In ShockBurst TM TX, the Data Ready (DR) signal is set high when a complete
package is transmitted, telling the MCU that the nRF905 is ready for new actions. It is
reset to low at the start of a new package transmission or when switched to a different
mode i.e. receive mode or standby mode.
In ShockBurst TM TX Auto Retransmit the Data Ready (DR) signal is set high at the
beginning of the pre-amble and is set low at the end of the preamble. The Data Ready
(DR) signal therefore pulses at the beginning of each transmitted data packet.
In ShockBurst TM RX, the signal is set high when nRF905 has received a valid
package, i.e. a valid address, package length and correct CRC. The MCU can then
retrieve the payload via the SPI interface. The Data Ready (DR) pin is reset to low
once the data has been clocked out of the data buffer or the device is switched to
transmit mode.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 28 of 36 June 2004
Auto Retransmit
One way to increase system reliability in a noisy environment or in a system without
collision control is to transmit a package several times. This is easily accomplished
with the Auto Retransmit feature in nRF905. By setting the AUTO_RETRAN bit to
“1” in the configuration register, the circuit keeps sending the same data package as
long as TRX_CE and TX_EN is high. As soon as TRX_CE is set low the device will
finish sending the packet it is currently transmitting and then return to standby mode.
RX Reduced Power Mode
To maximize battery lifetime in application where the nRF905 high sensitivity is not
necessary; nRF905 offers a built in reduced power mode. In this mode, the receive
current consumption reduces from 12.5mA to only 10.5mA. The sensitivity is reduced
to typical –85dBm, ±10dB. Some degradation of the nRF905 blocking performance
should be expected in this mode. The reduced power mode is an excellent option
when using Carrier Detect to sense if the wanted channel is available for outgoing
data.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 29 of 36 June 2004
APPLICATION EXAMPLE, DIFFERENTIAL CONNECTION TO
A LOOP ANTENNA
C2
22pF
0603
C6
4.7nF
0603
C5
33pF
0603
R2
22K
0603
C7
10nF
0603
VDD
C1
22pF
0603
R1
1M
X1
16 MHz
TRX_CE
1VSS 24
VSS 18
VDD 17
VSS
16
PWR_UP
2
uPCLK
3
VDD
4
VSS
5
CD
6
AM
7
DR
8
VSS
9
MISO
10
MOSI
11
SCK
12
XC2
15 XC1
14 CSN
13
VDD_PA 19
ANT1 20
ANT2 21
VSS 22
IREF 23
nRF905
VDD 25
VSS 26
VSS 27
VSS 28
VSS 29
VSS 30
DVDD_1V2 31
TXEN 32
U1
nRF905
VDD
C4
3.3nF
0603
C8
33pF
0603
VDD
TXEN
TRX_CE
PWR_UP
CD
AM
DR
SPI_MISO
SPI_MOSI
SPI_SCK
SPI_CSN
uPCLK
C3
33pF
R3
18K
C10
4.7pF
C11
5.6pF
aaaaaaaa
J1
Loop Antenna
9.5x9.5mm
C9
3.9pF
aaaaaaaa
aaaaaaaa
aaaaaaaa
Figure 11 nRF905 Application schematic, differential connection to a loop antenna
(868MHz).
Component Description Size Value Tol. Units
C1 NP0 ceramic chip capacitor, (Crystal oscillator) 0603 22 ±5% pF
C2 NP0 ceramic chip capacitor, (Crystal oscillator) 0603 22 ±5% pF
C3 NP0 ceramic chip capacitor, (PA supply decoupling) 0603 33 ±5% pF
C4 X7R ceramic chip capacitor, (PA supply decoupling) 0603 3.3 ±10% nF
C5 NP0 ceramic chip capacitor, (Supply decoupling) 0603 33 ±5% pF
C6 X7R ceramic chip capacitor, (Supply decoupling) 0603 4.7 ±10% nF
C7 X7R ceramic chip capacitor, (Supply decoupling) 0603 10 ±10% nF
C8 NP0 ceramic chip capacitor, (Supply decoupling) 0603 33 ±5% pF
C9 NP0 ceramic chip capacitor, (Antenna tuning) 0603 3.9 ±0.1 pF
C10 NP0 ceramic chip capacitor, (Antenna tuning) 0603 4.7 ±0.1 pF
C11 NP0 ceramic chip capacitor, (Antenna tuning) 0603 5.6 ±0.1 pF
R1 0.1W chip resistor, (Crystal oscillator bias) 0603 1 ±1% MΩ
R2 0.1W chip resistor, (Reference bias) 0603 22 ±1% kΩ
R3 0.1W chip resistor, (Antenna Q reduction) 0603 18 ±1% kΩ
U1 nRF905 Transceiver QFN32L/5x5
X1 Crystal LxWxH =
4.0x2.5x0.8 16 ±30ppm MHz
Table 15 Recommended external components, differential connection to a loop
antenna (868MHz).
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 30 of 36 June 2004
PCB LAYOUT EXAMPLE, DIFFERENTIAL CONNECTION TO A
LOOP ANTENNA
Figure 12 shows a PCB layout example for the application schematic in Figure 11. A
double-sided FR-4 board of 1.6mm thickness is used. This PCB has a ground plane on
the bottom layer. Additionally, there are ground areas on the component side of the
board to ensure sufficient grounding of critical components. A large number of via
holes connect the top layer ground areas to the bottom layer ground plane. There is no
ground plane beneath the antenna.
a) Top silk screen
No components in bottom layer
b) Bottom silk screen
c) Top view d) Bottom view
Figure 12 PCB layout example for nRF905, differential connection to a loop antenna.
A fully qualified RF-layout for the nRF905 and its surrounding components,
including antennas and matching networks, can be downloaded from
www.nordicsemi.no.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 31 of 36 June 2004
APPLICATION EXAMPLE, SINGLE ENDED CONNECTION TO
50Ω ANTENNA
C2
15pF
0603
C6
4.7nF
0603
C5
33pF
0603
R2
22K
0603
C7
10nF
0603
VDD
C1
15pF
0603
R1
1M
J2
SMA
50 ohm RF I/O
X1
16 MHz
XC1 XC2
TRX_CE
1VSS 24
VSS 18
VDD 17
VSS
16
PWR_UP
2
uPCLK
3
VDD
4
VSS
5
CD
6
AM
7
DR
8
VSS
9
MISO
10
MOSI
11
SCK
12
XC2
15 XC1
14 CSN
13
VDD_PA 19
ANT1 20
ANT2 21
VSS 22
IREF 23
nRF905
VDD 25
VSS 26
VSS 27
VSS 28
VSS 29
VSS 30
DVDD_1V2 31
TXEN 32
U1
nRF905
VDD
L1
0603
C3
0603
C11
Not fitted
0603
C12
0603
L3
0603
L2
0603
C9
0603
C10
0603
C4
3.3nF
0603
C8
33pF
0603
VDD
VDD
1
2
J1
1.9-3.6V
GND
S1
VDD Select C14
100nF
0603
C13
0603
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
JP1
HEADER 16
TRX_CE
PWR_UP
CD
AM
DR
MISO
SCK
CSN
TXEN
VDD_C
+C15
4.7uF/16V
3216
VDD_C
VDD_C VDD_C
MOSI
1
2
J3
R3
10K
0603
R5
10K
0603
VDD
R4
10K
0603
uPCLK
GND
uPCLK
1
J4
GND
C3
C9
C10
C11
C12
C13
L1
L2
L3
868/915MHz 433MHz
33pF, ±5%
3.9pF, ±0.25pF
3.9pF, ±0.25pF
Not fitted Not fitted
33pF, ±5%
Not fitted
12nH, 5%
12nH, 5%
12nH, 5%
180pF, ±5%
18pF, ±5%
18pF, ±5%
6.8pF, ±5%
Not fitted
12nH, 5%
39nH, 5%
39nH, 5%
xxx
xxx
xxx
xxx
Figure 13 nRF905 Application schematic, single ended connection to 50Ω antenna by
using a differential to single ended matching network.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 32 of 36 June 2004
Component Description Size Value Tol. Units
C1 NP0 ceramic chip capacitor, (Crystal oscillator) 0603 22 ±5% pF
C2 NP0 ceramic chip capacitor, (Crystal oscillator) 0603 22 ±5% pF
C3 NP0 ceramic chip capacitor, (PA supply decoupling)
@ 433MHz
@ 868MHz
@ 915MHz
0603 180
33
33
±5% pF
C4 X7R ceramic chip capacitor, (PA supply decoupling) 0603 3.3 ±10% nF
C5 NP0 ceramic chip capacitor, (Supply decoupling) 0603 33 ±5% pF
C6 X7R ceramic chip capacitor, (Supply decoupling) 0603 4.7 ±10% nF
C7 X7R ceramic chip capacitor, (Supply decoupling) 0603 10 ±10% nF
C8 NP0 ceramic chip capacitor, (Supply decoupling) 0603 33 ±5% pF
C9 NP0 ceramic chip capacitor, (Impedance matching)
@ 433MHz
@ 868MHz
@ 915MHz
0603 18
3.9
3.9
±5%
<±0.25pF
<±0.25pF
pF
C10 NP0 ceramic chip capacitor, (Impedance matching)
@ 433MHz
@ 868MHz
@ 915MHz
0603 18
3.9
3.9
±5%
<±0.25pF
<±0.25pF
pF
C11 NP0 ceramic chip capacitor, (Impedance matching) 0603 Not fitted pF
C12 NP0 ceramic chip capacitor, (Impedance matching)
@ 433MHz
@ 868MHz
@ 915MHz
0603 6.8
33
33
±5%
±5%
±5%
pF
C13 NP0 ceramic chip capacitor, (Impedance matching)
@ 433MHz
@ 868MHz
@ 915MHz
0603 Not fitted
Not fitted
Not fitted
pF
L1 Chip inductor, (Impedance matching)
@ 433MHz: SRF> 433MHz
@ 868MHz: SRF> 868MHz
@ 915MHz: SRF> 915MHz
0603 12
12
12
±5% nH
L2 Chip inductor, (Impedance matching)
@ 433MHz: SRF> 433MHz
@ 868MHz: SRF> 868MHz
@ 915MHz: SRF> 915MHz
0603 39
12
12
±5%
±5%
±5%
nH
L3 Chip inductor, (Impedance matching)
@ 433MHz: SRF> 433MHz
@ 868MHz: SRF> 868MHz
@ 915MHz: SRF> 915MHz
0603 39
12
12
±5%
±5%
±5%
nH
R1 0.1W chip resistor, (Crystal oscillator bias) 0603 1 ±1% MΩ
R2 0.1W chip resistor, (Reference bias) 0603 22 ±1% kΩ
U1 nRF905 Transceiver QFN32L/5x5
X1 Crystal LxWxH =
4.0x2.5x0.8 16 ±30ppm MHz
Table 16 Recommended external components, single ended connection to 50Ω
antenna.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 33 of 36 June 2004
PCB LAYOUT EXAMPLE, SINGLE ENDED CONNECTION TO
50Ω ANTENNA
Figure 14 shows a PCB layout example for the application schematic in Figure 13. A
double-sided FR-4 board of 1.6mm thickness is used. This PCB has a ground plane on
the bottom layer. Additionally, there are ground areas on the component side of the
board to ensure sufficient grounding of critical components. A large number of via
holes connect the top layer ground areas to the bottom layer ground plane.
a) Top silk screen
No components in bottom layer
b) Bottom silk screen
c) Top view d) Bottom view
Figure 14 PCB layout example for nRF905, single ended connection to 50Ω antenna
by using a differential to single ended matching network.
A fully qualified RF-layout for the nRF905 and its surrounding components,
including antennas and matching networks, can be downloaded from
www.nordicsemi.no.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 34 of 36 June 2004
DEFINITIONS
Data sheet status
Objective product specification This datasheet contains target specifications for product development.
Preliminary product
specification This datasheet contains preliminary data; supplementary data may be
published from Nordic Semiconductor ASA later.
Product specification This datasheet contains final product specifications. Nordic Semiconductor
ASA reserves the right to make changes at any time without notice in order to
improve design and supply the best possible product.
Limiting values
Stress above one or more of the limiting values may cause permanent damage to the device. These are stress
ratings only and operation of the device at these or at any other conditions above those given in the
Specifications sections of the specification is not implied. Exposure to limiting values for extended periods may
affect device reliability.
Application information
Where application information is given, it is advisory and does not form part of the specification.
Table 17 Definitions.
Nordic Semiconductor ASA reserves the right to make changes without further notice
to the product to improve reliability, function or design. Nordic Semiconductor does
not assume any liability arising out of the application or use of any product or circuits
described herein.
LIFE SUPPORT APPLICATIONS
These products are not designed for use in life support appliances, devices, or systems
where malfunction of these products can reasonably be expected to result in personal
injury. Nordic Semiconductor ASA customers using or selling these products for use
in such applications do so at their own risk and agree to fully indemnify Nordic
Semiconductor ASA for any damages resulting from such improper use or sale.
Product specification revision date: 07.06.2004
Datasheet order code: 070604nRF905
All rights reserved ®. Reproduction in whole or in part is prohibited without the prior
written permission of the copyright holder.
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 35 of 36 June 2004
YOUR NOTES
PRODUCT SPECIFICATION
nRF905 Single Chip 433/868/915 MHz Radio Transceiver
Main office: Nordic Semiconductor ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone +4772898900 -Fax +4772898989
Revision: 1.1 Page 36 of 36 June 2004
Nordic Semiconductor ASA – World Wide Distributors
For Your nearest dealer, please see http://www.nordicsemi.no
Main Office:
Vestre Rosten 81, N-7075 Tiller, Norway
Phone: +47 72 89 89 00, Fax: +47 72 89 89 89
Visit the Nordic Semiconductor ASA website at http://www.nordicsemi.no
