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preliminary product specification main office: nordic vlsi asa - vestre rosten 81, n-7075 tiller, norway - phone +4772898900 - fax +4772898989 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 m a supply current in power down mode <10 n a 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 +4772898900 - fax +4772898989 revision: 1.0 page 2 of 13 april 2000 block diagram rext crystal oscillator xtal fsk ant1 frequency synthesizer power amplifier phase detector vco loop 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 +4772898900 - fax +4772898989 revision: 1.0 page 3 of 13 april 2000 electrical specifications conditions: vdd = +3v, vss = 0v, t a = - 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 m a i dd supply current power down mode 10 100 na fsk modulation d 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 v dd - 0.5 v dd v v il low level input voltage vss 0.3 v v oh high level output voltage v dd - 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 w . 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 +4772898900 - fax +4772898989 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. a a 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 v i ...................... - 0.3v to vdd + 0.3v output voltage v o ..................... - 0.3v to vdd + 0.3v total power dissipation p d (t a =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. a 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 +4772898900 - fax +4772898989 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 tx 2ms clk 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 +4772898900 - fax +4772898989 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 +4772898900 - fax +4772898989 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 v dd , 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 200- 700 w . a load impedance of 400 w is recommended if maximum output power (10dbm) is needed. lower load impedance (for instance 50 w ) can be obtained by fitting a simple matching network or a rf transformer (balun). the 50 w 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 +4772898900 - fax +4772898989 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 +4772898900 - fax +4772898989 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 m a 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 30 m s. 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 [c ml ] to the xo8 pin will result in an increase in the current consumption, the increase d i is given as: d i = f xo8 vdd c ml example with a capacitive load of c ml = 5pf, using vdd=3.0 v and a 13.567 mhz crystal, the current increase d i becomes : d 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 c ml =5 pf.
preliminary product specification NRF902 single chip 868 mhz transmitter nordic vlsi asa - vestre rosten 81, n-7075 tiller, norway - phone +4772898900 - fax +4772898989 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: pf co 3 crystal parallel equivalent capacitor ohm esr 50 . crystal equivalent series resistor pf c l 12 = 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 22k w 10dbm 30ma 82k w 0dbm 15ma 180k w -10dbm 9ma conditions: vdd = 3.0v, vss = 0v, t a = 27oc, load impedance = 400 w . 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 +4772898900 - fax +4772898989 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 +4772898900 - fax +4772898989 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: +47 72 89 89 00, fax: +47 72 89 89 89 e-mail: nrf@nvlsi.no visit the nordic vlsi asa website at http://www.nvlsi.no

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