Datasheet nRF902 Datasheet (Nordic VLSI)

PRELIMINARY PRODUCT SPECIFICATION

Main office: Nordic VLSI ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]

Revision: 1.0 Page 1 of 13 April 2000

Single chip 868 MHz Transmitter

FEATURES APPLICATIONS

• True single chip FSK/ASK transmitter in

a small 8-pin package

• Automatic Meter Reading

• Keyless entry

• Adjustable output power up to +10dBm • Wireless data communication

• FSK data rate up to 50kbits/s • Alarm and security systems

• Very few external components • Home Automation

• On-chip frequency synthesiser gives

improved frequency stability compared to
SAW solutions

• Remote control

• Surveillance

• Automotive

• Wide power supply range: 2.4 to 3.6 V • Telemetry

• Low supply current, typical 9mA

@ -10dBm output power

• Toys

• Power Down and Clock modes makes

power saving easy

• Reference Clock output pin for

microcontroller

GENERAL DESCRIPTION

nRF902 is a single-chip transmitter for the 868 MHz ISM band, designed to comply
with the ETSI specification I-ETS 300 220. Using nRF902 both FSK and ASK
modulation is possible. The transmitter consists of a fully integrated frequency
synthesiser, a power amplifier, a crystal oscillator and a modulator. Few external
components are required: a 13.567 MHz crystal, two resistors and some decoupling
capacitors. Due to the use of the crystal-oscillator stabilised frequency synthesiser,
frequency drift is much lower than in comparable SAW-resonator based solutions.
Output power is easily programmable by use of an external resistor. Current
consumption is very low, only 9 mA at an output power of –10dBm. Built-in Clock
and Power Down modes makes power saving and duty-cycling easily realisable.

QUICK REFERENCE DATA

Parameter Value Unit

Minimum supply voltage 2.4 V
Maximum output power 10 dBm
Maximum FSK data rate 50 kbit/s
Maximum ASK data rate 10 kbit/s
Supply current FSK transmitter @ -10dBm output power 9 mA
Supply current in Clock mode 200

µA

Supply current in Power Down mode <10

nΑ

Table 1. nRF902 quick reference data

nRF902

PRELIMINARY PRODUCT SPECIFICATION

nRF902 Single chip 868 MHz Transmitter

Nordic VLSI ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Revision: 1.0 Page 2 of 13 April 2000

BLOCK DIAGRAM

REXT

Crystal
Oscillator

xtal

FSK

ant1

Frequency synthesizer

Power
Amplifier

Phase
Detector

VCOLoop

Filter

Prescaler

1/64

ant2

1/8

Clock
Divider

XO8

Figure 1. nRF902 block diagram

PIN FUNCTIONS

Pin Name Pin function Description

1 xtal Input Crystal pin / Power Up
2 REXT Input Power adjust / Clock Mode / ASK modulation digital input
3 XO8 Output Reference Clock Output (Crystal Frequency / 8)
4 VDD Input Positive Supply (2.4 - 3.6V)
5 FSK Input Digital Data Input
6 ant2 Power/Output Antenna output 1
7 ant1 Power/Output Antenna output 2
8 VSS Power Ground (0V)

Table 2. nRF902 pin functions

PIN ASSIGNMENT

FSK

VSS

7

6

5

8

ant2

ant1

xtal

REXT

XO8

VDD

1

2

3

4

nRF902

Figure 2. nRF902 pin assignment

PRELIMINARY PRODUCT SPECIFICATION

nRF902 Single chip 868 MHz Transmitter

Nordic VLSI ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Revision: 1.0 Page 3 of 13 April 2000

ELECTRICAL SPECIFICATIONS

Conditions: VDD = +3V, VSS = 0V, TA = - 40ºC to + 85ºC

Symbol Parameter (condition) Notes Min. Typ. Max. Units

Operating conditions

f

TX

Transmit frequency 1) 868 870 MHz

f

XTAL

Crystal frequency 1) 13.563 13.593 MHz

V

DD

Supply voltage 2.4 3.6 V

Tamb Operating temperature - 40 + 85

°C

P

RF

Maximum Output Power 3) 10 dBm

I

DD

Supply current CLOCK Mode 2) 200 300

µA

I

DD

Supply current POWER DOWN Mode 10 100 nA

FSK modulation

∆f

Frequency deviation 10 20 30 kHz

R

FSK

FSK data rate 50 kbit/s

I

DD

Supply current @ 10dBm output power 3) 30 37 mA

I

DD

Supply current @ -10dBm output power 3) 9 17 mA

ASK modulation

R

ASK

ASK data rate 0 10 kbit/s

P

RF1

Transmitted power at data = ‘1’ 10 dBm

P

RF0

Transmitted power at data = ‘0’ -50 dBm

I

DD

Supply current @ 10dBm output power 3) 30 37 mA

I

DD

Supply current @ -50dBm output power 3) 200 300 uA

FSK input pin

V

IH

HIGH level input voltage VDD - 0.5 V

DD

V

V

IL

LOW level input voltage Vss 0.3 V

V

OH

HIGH level output voltage VDD - 0.5 V

DD

V

V

OL

LOW level output voltage Vss 0.3 V

NOTES:

1) The crystal frequency may be altered to produce any desired frequency within the 868MHz to 870MHz band.

2) Measured with no load on XO8 output pin.

3) Antenna load impedance = 400 Ω.

Table 3. nRF902 electrical specifications

PRELIMINARY PRODUCT SPECIFICATION

nRF902 Single chip 868 MHz Transmitter

Nordic VLSI ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Revision: 1.0 Page 4 of 13 April 2000

PACKAGE OUTLINE

nRF902, uses the SOIC 8 package. Dimensions are in mm.

Package Type D E H A A

1

e b L Copl.

αα

SOIC 8

Min

Max

4.80

4.98

3.81

3.99

5.84

6.20

1.55

1.73

0.127

0.250

1.27

0.35

0.49

0.41

0.89 0.25

0°
8°

Figure 3. Package outline.

Absolute Maximum Ratings

Supply voltages

VDD............................. - 0.3V to + 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)...........................220mW

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.

α

A

1

A

L

E H

D

1 2 3 4

8 7 6 5

e b

PRELIMINARY PRODUCT SPECIFICATION

nRF902 Single chip 868 MHz Transmitter

Nordic VLSI ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Revision: 1.0 Page 5 of 13 April 2000

IMPORTANT TIMING DATA

Timing information

The timing information for the different operations is summarised in Table 4.
(TX is Transmit mode, Clk is Clock mode, Pwr_Dn is Power Down Mode.)

Change of Mode Max Delay

Pwr_Dn è TX 2ms

Clk è TX 30us

Table 4 Switching times for nRF902

Switching between Power Down Mode and Transmit-mode.

The maximum time from Power Down mode until the synthesised frequency is stable
and data can be transmitted is seen in Figure 4.

Figure 4. Timing diagram when going from Power Down mode to Transmit-mode

Switching between Clock Mode and Transmit-mode.

The maximum time from Clock mode until the synthesised frequency is stable and
data can be transmitted is seen in Figure 5.

Figure 5. Timing diagram when going from Clock mode to Transmit-mode

xtal

VDD

ms

FSK

0 2 4

2ms

REXT

VDD

us

FSK

0 30

30us

PRELIMINARY PRODUCT SPECIFICATION

nRF902 Single chip 868 MHz Transmitter

Nordic VLSI ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Revision: 1.0 Page 6 of 13 April 2000

APPLICATION INFORMATION

FSK Transmit mode

FSK modulation is realised by feeding the modulating data to the digital FSK input
pin (see Figure 6).

Matching Network/

Antenna

X1 13.567MHz

REXT

xtal

XO8

VDD

1

2

3

4

VDD

C

1

C
2

VDD

R2

R1

Clock

Output

FSK

VSS

8

ant1

Data

Input

ant2

VDD

nRF902

5

7

6

Figure 6. FSK transmitter in FSK Transmit mode

In applications where high data rate and low spectrum bandwidth is required an
external varactor may be used to modulate the crystal. For optimum bandwidth usage
a low pass filter should be used to shape the input bit stream, (see Figure 7).

X1 13.567MHz

REXT

xtal

XO8

VDD

1

2

3

4

VDD

C1

C2

VDD

R2

R1

Clock

Output

VDD

Matching Network/

Antenna

ant1

ant2

VSS

FSK

Data

Input

nRF902

8

7

6

5

Figure 7. FSK transmitter in FSK Transmit mode for low spectral bandwidth

PRELIMINARY PRODUCT SPECIFICATION

nRF902 Single chip 868 MHz Transmitter

Nordic VLSI ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Revision: 1.0 Page 7 of 13 April 2000

ASK modulation.

ASK modulation can be realised by using the REXT pin (see Figure 8). When R2 is
connected to VDD, the chip transmits a carrier. When the bias resistor is connected to
VSS then the internal output power amplifier is turned off. These two situations
represent logic ‘1’ and logic ‘0’ in an ASK system. When ASK modulation is used,
the FSK pin must be connected to VDD.

Matching Network/

Antenna

X1 13.567MHz

REXT

xtal

XO8

VDD

1

2

3

4

VDD

R2

R1

Clock

Output

FSK

VSS

8

ant1

Data

Input

ant2

VDD

7

6

5

C1

C2

VDD

nRF902

Figure 8. FSK transmitter in ASK Transmit mode

Antenna output

The “ant” output pins provide a balanced RF output to the antenna. The pins must
have a DC path to VDD, either via a RF choke or via the centre point in a loop antenna.
The load impedance seen between the ant1/ant2 outputs should be in the range 200­700Ω. A load impedance of 400Ω is recommended if maximum output power
(10dBm) is needed. Lower load impedance (for instance 50 Ω) can be obtained by

fitting a simple matching network or a RF transformer (balun). The 50 Ω load can
also be connected directly between the ant1/ant2 pins, but this will result in higher
current consumption for a given output power to the antenna.

Note: Application notes of antenna layout solutions with matching networks will soon
be available on our website: http://www.nvlsi.no.

PRELIMINARY PRODUCT SPECIFICATION

nRF902 Single chip 868 MHz Transmitter

Nordic VLSI ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Revision: 1.0 Page 8 of 13 April 2000

Power Down mode

Power Down mode is used to achieve very low current consumption. Effectively the
chip is disabled with minimal leakage current consumption, typically less than 10nA.
Operating in this mode when not transmitting data, i.e. low duty cycle systems can
significantly increase battery lifetime.

The resistor R1 connected from the crystal pin towards VDD supplies the crystal
oscillator with bias current (see Figure 9). When this resistor is connected to VSS or
left open, the chip enters Power Down mode. As shown in Figure 9 the resistor R1 is
connected to the “Power Down” terminal, this can be controlled by a micro-controller,
hence eliminating the need to switch off the power supply to the chip when not
transmitting. Start-up time when switching from Power Down mode to Transmit
mode is approximately 2 ms.

X1 13.567MHz

REXT

xtal

XO8

VDD

1

2

3

4

VDD

C1

C2

VDD

R2

R1

Clock

Output

Matching Network/

Antenna

FSK

VSS

8

ant1

Data

Input

ant2

Power

Down

7

6

5

nRF902

Figure 9. FSK transmitter in Power Down mode

PRELIMINARY PRODUCT SPECIFICATION

nRF902 Single chip 868 MHz Transmitter

Nordic VLSI ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Revision: 1.0 Page 9 of 13 April 2000

Clock mode

Clock mode is available so that an external microprocessor may have a reference
signal without the cost of a second crystal. In Clock mode, the crystal oscillator and
reference clock outputs are operating, while the rest of the transmitter is disabled. The
reference signal from the internal crystal oscillator is divided by 8 by use of a
prescaler, this signal is available at the XO8 pin.

Clock mode may be set by connecting the power adjusting resistor R2 to ground or by
leaving it open (see Figure 10). Current consumption in Clock mode is typically 200
µA when no load is applied at the XO8 clock output pin. If a capacitive load is
applied at the XO8 output, then current consumption in Clock mode will increase.
Start-up time when switching between Clock mode and Transmit mode is extremely
fast, typically 30µs.

xtal

XO8

VDD

1

2

3

4

R2

R1

Clock

Output

Matching Network/

Antenna

FSK

VSS

8

ant1

Data

Input

ant2

X1 13.567MHz

REXT

VDD

C1

C2

VDD

nRF902

7

6

5

Figure 10. FSK transmitter in Clock mode

XO8 Clock Output Pin Capacitance

The frequency of the clock signal is 1/8th of the crystal frequency i.e. a crystal
frequency of 13.567 MHz will result in an output clock frequency of 1.695 MHz. The
XO8 output signal will be present in Transmit mode and Clock mode. In Power Down
mode the XO8 signal will be a logic “0”.

The capacitive load at the XO8 pin will affect current consumption in Clock mode. If
the pin is left open the current consumption will typically be 200uA. Adding a
capacitive load, such as microcontroller load [CML] to the XO8 pin will result in an
increase in the current consumption, the increase ∆I is given as:

∆I = f

XO8

⋅VDD⋅ C

ML

Example

With a capacitive load of CML = 5pF, using VDD=3.0 V and a 13.567 MHz crystal,
the current increase ∆I becomes :

∆I = f

XO8

⋅VDD⋅ C

ML

= ((13 .567 MHz) / 8) ⋅ 3.0 V ⋅ 5 pF = 25 uA.

The typical current consumption will increase to 225uA when adding CML=5 pF.

PRELIMINARY PRODUCT SPECIFICATION

nRF902 Single chip 868 MHz Transmitter

Nordic VLSI ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Revision: 1.0 Page 10 of 13 April 2000

Crystal Specification

Modulation is achieved by pulling of the crystal capacitance. As such to achieve
correct frequency deviation (20kHz) and frequency of operation as specified in Table
3 the crystal must meet the following specification:

pFCo 3

≤

Crystal parallel equivalent capacitor

ohmESR 50

≤

. Crystal equivalent series resistor

pFCL12= Crystal load capacitor

Output Power adjustment

A bias resistor R2 (see Figure 6) should be connected from the REXT pin to the
positive power supply VDD. The value of this resistor determines the output power
level. See table 5 for choice of R2 value.

Power setting resistor R2 RF output power DC current consumption

22kΩ

10dBm 30mA

82kΩ

0dBm 15mA

180kΩ

-10dBm 9mA

Conditions: VDD = 3.0V, VSS = 0V, TA = 27ºC, Load impedance = 400 Ω.

Table 5. RF output power setting for the nRF902.

PRELIMINARY PRODUCT SPECIFICATION

nRF902 Single chip 868 MHz Transmitter

Nordic VLSI ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Revision: 1.0 Page 11 of 13 April 2000

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 VLSI ASA later.

Product specification This datasheet contains final product specifications. Nordic VLSI 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 6. Definitions.

Nordic VLSI ASA reserves the right to make changes without further notice to the
product to improve reliability, function or design. Nordic VLSI 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 VLSI ASA customers using or selling these products for use in such
applications do so at their own risk and agree to fully indemnify Nordic VLSI ASA
for any damages resulting from such improper use or sale.

Preliminary specification: Revision Date: 06/04/2000.

Datasheet order code: 060400-nRF902.

All rights reserved ®. Reproduction in whole or in part is prohibited without the prior
written permission of the copyright holder.

PRELIMINARY PRODUCT SPECIFICATION

nRF902 Single chip 868 MHz Transmitter

Nordic VLSI ASA - Vestre Rosten 81, N-7075 Tiller, Norway - Phone [phone] - Fax [phone]
Revision: 1.0 Page 12 of 13 April 2000

YOUR NOTES

PRELIMINARY PRODUCT SPECIFICATION

nRF902 Single chip 868 MHz Transmitter

Revision 1.0 April 2000

Nordic VLSI ASA – World Wide Distributors

For Your nearest dealer, please see http://www.nvlsi.no

Main Office:

Vestre Rosten 81, N-7075 Tiller, Norway

Phone: [phone], Fax: [phone]

E-mail: [e-mail]

Visit the Nordic VLSI ASA website at http://www.nvlsi.no