TX2 / RX2

 

 

The TX2 and RX2 data link modules are a miniature PCB mounting UHF radio transmitter and receiver pair which enable the simple implementation of a data link at up to 160 kbit/s at distances up to 75 metres in-building and 300 metres open ground.

Features

• CE Certified by independent Notified Body
• Verified to comply with harmonised radio standard ETSI EN 300 220-3 by accredited Test Laboratory
• Verified to comply with harmonised EMC standard ETSI EN 301 489-3 by accredited Test Laboratory
• Data rates up to 160kbps
• Usable range up to 300m
• Fully screened

Available for operation at 433.92 MHz in Europe (including UK), both modules combine full screening with extensive internal filtering to ensure EMC compliance by minimising spurious radiations and susceptibilities. The TX2 and RX2 modules will suit one-to-one and multi-node wireless links in applications including car and building security, EPOS and inventory tracking, remote industrial process monitoring and computer networking. Because of their small size and low power requirements, both modules are ideal for use in portable, battery-powered applications such as hand-held terminals.

Technical Summary

Transmitter

• 2 stage crystal controlled, FM modulated at up to 160kbps
• Operation from 2.2V to 6V @ 10mA
• +9dBm RF output on 433.92MHz
• High power efficiency, typically 35% DC ® RF@ 3V supply
• Improved frequency and deviation accuracy
• 2nd harmonics <-60dBc

Receiver

• Double conversion NBFM superhet
• SAW front end filter, image rejection >50dB
• Supply 3.3V to 6.0V @ 13mA
• -107dBm sensitivity @ 1ppm BER @ 14kbps
• Carrier Detect output
• LO leakage <-60dBm

Evaluation Platform: Universal Evaluation kit or Narrow Band Evaluation Kit

Functional description

The TX2 transmitter module is a two stage, SAW controlled FM transmitter operating between 2 and 6 V and is available in 433.92MHz and 418.00 MHz versions. The 433.92 MHz unit is type-approved to EN 300 220-3 for European use and will deliver +9 dBm from a 5V supply at 12mA, while the 418.00 MHz unit has MPT 1340 type-approval for U.K. use and deliveres -6dBm from a 5V supply at 5mA. Both modules measure 12 x 32 x 3.8 mm.

The RX2 module is a double conversion FM superhet receiver capable of handling date rates of upto 160kbit/s. The SIL style RX2 receiver measures 48 x 17.5 x 4.5 mm. It will operate from a supply of 3-6V and draws just 14mA when receiving. A fast-acting carrier detect and a power-up enable time of less than 1µs. This allows effective duty cycle power saving and a -107dBm sensitivity. This, combined with a SAW front-end filter results in an excellent RF performance and EMC conformance.

Figure 1: TX2 block diagram

Figure 2: TX2 physical dimension

Pin description - TX2

RF GND	Pin 1	RF ground, internally connected to the module screen and pin 4 (0V). This pin should be directly connected to the RF return path - e.g. coax braid, main PCB ground plane etc.
RF out	Pin 2	50W RF output to antenna. Internally DC-isolated. See antenna section for details of suitable antennas / feeds.
Vcc	Pin 3	+ve supply pin. The module will generate RF when the Vcc supply is present. Max ripple content 0.1Vp-p. A 100nF de-coupling ceramic capacitor is suggested.
0 V	Pin 4	DC supply ground. Internally connected to pin 1 and module screen.
TXD	Pin 5	This DC coupled modulation input will accept either serial digital data ( 0 V to Vcc levels) or high level linear signals. Input impedance is 100 kW.

 

RX2 receiver

Figure 3: RX2 block diagram

Figure 4: RX2 physical dimension

Pin description RX2

RF in	Pin 1	50W RF input from antenna. Internally DC-isolated. See antenna section for suggested antennas and feeds.
RF GND	Pin 2	RF ground, internally connected to the module screen and pin 4 (0V). This pin should be directly connected to the RF return path - e.g. coax braid, main PCB ground plane etc.
CD	Pin 3	The Carrier Detect may be used to drive an external PNP transistor to obtain a logic level carrier detect signal, see test circuit / applications note. If not required it should be connected to pin 5 (Vcc).
0 V	Pin 4	DC supply ground. Internally connected to pin 1 and module screen.
Vcc	Pin 5	+ve supply pin. +3.0 to +6.0V @ <17mA . The supply must be clean <2mVp-pripple. A 10µF de-coupling capacitor and 10W series resistor is recommended if a clean supply is not available.
AF	Pin 6	This is a buffered and filtered analogue output from the FM demodulator. It has a standing DC bias of 1.2V and 400mVp-p base band signal. It is useful as a test point or to drive linear decoders. Load impedance should be > 2kW and <100pF.
RXD	Pin 7	This digital output from the internal data slicer is a squared version of the signal on pin 6 (AF). It may be used to drive external decoders. The data is true data, i.e. as fed to the transmitter. Load impedance should be > 1kW and <1nF.

 

Absolute maximum ratings

Exceeding the values given below may cause permanent damage to the module.

Operating temperature -10*C to +55*C
Storage temperature -40*C to +100*C

TX2 all variants
Vcc (pin 3) -0.1V to +10.0V
TXD (pin 5) -0.1V to +10.0V
RF out (pin 2) ±50V @ <10MHz, +20dBm @ >10MHz

RX2
Vcc, (pins 7, 9) -0.1V to +10.0V
RXD, AF, CD (pins 7, 6, 3) -0.1V to +Vcc
RF in (pin 1) ±50V @ <10MHz, +13dBm @ >10MHz

Note: Operation of the TX2 above 6V may cause the module to exceed the licenced power level

Performance specification: TX2 transmitter

(temperature = 20°C unless stated)

General	pin	min.	typ.	max.	units	notes
DC supply
Supply voltage (3V version)	3	2.2	3.0	4.0	V
Supply Current	3	4	6	10	mA
Supply voltage (5V version)	3	4.0	5.0	6.0	V
Supply Current	3	7	10	14	mA
RF
RF power output @ Vcc=3V	3	0	+4	+6	dBm	1
RF power output @ Vcc = 5V	3	+6	+9	+12	dBm	1
2nd harmonics	2	-	-65	-54	dBc	1
Harmonics @ >1GHz	2	-	-50	-40	dBc	1
FM deviation (peak)		±20	±25	±30	kHz
Initial frequency accuracy		-30	0	+30	kHz
Overall frequency accuracy		-70	-	+70	kHz	4
Baseband
Modulation bandwidth @ -3dB		DC	-	20	kHz
Modulation bandwidth @ -3dB		DC	-	100	kHz	2
Modulation distortion (THD)		-	5	10	%
Dynamic timing
Power-up time (En ® full RF)		-	-	100	ms

Notes:
1. Measured into 50W resistive load.
2. 160kbps version

Performance specification: RX2 receiver

(Vcc = 5.0V / temperature = 20°C unless stated)

General	pin	min.	typ.	max.	units	notes
DC Level
Supply voltage, Vcc standard	5	4.0	5.0	6.0	V
Supply voltage, Vcc, 3V version	5	3.3	3.5	4.0	V
Supply current	5	11	13	17	mA
Supply ripple	5	-	-	2	mVp-p
Data throughput high, 100mA source	7	-	Vcc-0.6	-	V
Data throughput low, 100mA sink	7	-	0.4	-	V
Load capacitance, AF / RXD	6, 7	-	-	100	mF
RF/IF
RF sensitivity @ 10dB (S+N)/N	1, 6	-107	-113	-	dBm	for 14kbps
RF sensitivity @ 10dB (S+N)/N	1, 6	-100	-107	-	dBm	for 40kbps
RF sensitivity @ 10dB (S+N)/N	1, 6	-	-96	-	dBm	for 160kbps
RF sensitivity @ 1ppm BER	1, 7	-100	-107	-	dBm	for 14kbps
RF sensitivity @ 1ppm BER	1, 7	-93	-100	-	dBm	for 40kbps
RF sensitivity @ 1ppm BER	1, 7	-	-90	-	dBm	for 160kbps
CD threshold	1, 3	-97	-107	-	dBm	for 14kbps
CD threshold	1, 3	-90	-100	-	dBm	for 40kbps
CD threshold	1, 3	-	-104	-	dBm	for 160kbps
IF bandwidth		-	250	-	kHz
Initial frequency accuracy	1	-30	0	+30	kHz
EMC
Image rejection (2 x FIF)	1	-	50	-	dB	2
Spurious response upto 1GHz	1	-	70	-	dB	2
LO leakage, conducted	1	-	-65	-	dBm
LO leakage, radiated		-	-70	-	dBm
AF Baseband
Baseband bandwidth @ -3dB	6	0.006	-	7	kHz	for 14kbps
Baseband bandwidth @ -3dB	6	0.060	-	20		for 40kbps
Baseband bandwidth @ -3dB	6	0.250	-	91		for 160kbps
AF level	6	-	450	-	mVp-p	5
DC offset on AF out	6	0.8	1.2	1.6	V
Distortion on recovered AF	6	-	0.5	1	%
Ultimate (S+N)/N	6	35	45	-	dB
Ultimate (S+N)/N	6	-	28	-	dB	for 160kbps
Dynamic timing
Power up with signal present
Power up to valid CD, TPU-CD		-	1	-	ms
Power up to stable Data, TPU-RXD		-	20	-	ms	for 14kbps
Power up to stable Data, TPU-RXD		-	5	-	ms	for 40kbps
Power up to stable Data, TPU-RXD		-	3	-	ms	for 160kbps
Power up to stable AF, TPU-AF		-	0.6	-	ms	for 160kbps
Power up to valid CD, TPU-CD		-	0.7	-	ms	for 160kbps
Signal applied with supply on
Signal to valid CD, TSIG-CD		-	0.5	-	ms
Signal to stable Data, TSIG-RXD		-	15	-	ms	for 14kbps
Signal to stable Data, TSIG-RXD		-	3	-	ms	for 40kbps
Signal to stable Data, TSIG-RXD		-	0.75	-	ms	for 160kbps
Signal to stable AF, TSIG-AF		-	0.1	-	ms	for 160kbps
Signal to stable CD, TSIG-CD		-	0.2	-	ms	for 160kbps
Time between data transitions	7	0.07	-	15	ms	for 14kbps, 4
Time between data transitions	7	0.025	-	1.5	ms	for 40kbps, 4
Time between data transitions	7	6.25		500	ms	for 160kbps, 4
Mark : space ratio	9	20	50	80	%	3

 

Notes:
1. For 6dB (S+N)/N degradation on wanted -100dBm signal
2. Receiver spurious responses are at FRF±(n x 15.92MHz), n=1, 2, 3 etc
3. Average over 30ms (14kbps), 3ms (40kbps), 1ms (160kbps) at maximum bit rate
4. Values for 50:50 mark to space (i.e. square wave)

 

Module test Circuits

 

 

Figure 5: TX2 test circuit

 

Figure 6: RX2 test circuit

 

Module mounting considerations

The modules may be mounted horizontally or vertically on an area of ground plane preferably close to the antenna to minimise feed length. The receiver and it's antenna should be kept away from sources of interference (micro's, SMPS etc.). The modules may be potted if required in a viscous compound which can not enter the screen can.

Warning: Do NOT wash the modules. They are not hermetically sealed.

Figure 7: module mounting options - please click below

Antenna requirements

Three types of integral antenna are recommended and approved for use with the module:
A) Helical: Wire coil, connected directly to pin 2, open circuit at other end. This antenna is very efficient given it's small size (20mm x 4mm dia.). The helical is a high Q antenna, trim the wire length or expand the coil for optimum results. The helical de-tunes badly with proximity to other conductive objects.
B) Loop: A loop of PCB track tuned by a fixed or variable capacitor to ground at the 'hot' end and fed from pin 2 at a point 20% from the ground end. Loops have high immunity to proximity de-tuning.
C) Whip: This is a wire, rod ,PCB track or combination connected directly to pin 2 of the module. Optimum total length is 17cm (1/4 wave @ 418MHz) Keep the open circuit (hot) end well away from metal components to prevent serious de-tuning. Whips are ground plane sensitive and will benefit from internal 1/4 wave earthed radial(s) if the product is small and plastic cased.

The antenna choice and position directly controls the system range. Keep it clear of other metal in the system, particularly the 'hot' end. The best position by far, is sticking out the top of the product. This is often not desirable for practical/ergonomic reasons thus a compromise may need to be reached. If an internal antenna must be used try to keep it away from other metal components, particularly large ones like transformers, batteries and PCB tracks/earth plane. The space around the antenna is as important as the antenna itself.

 

Figure 8: integral antenna configurations

Integral antenna summary:

	whip	helical	loop
Ultimate performance	***	**	*
Ease of design set-up	***	**	*
Size	*	***	**
Immunity to proximity effects	**	*	***
Range open ground (for TX2-433-40-5 & RX2-433-14-5)	300	200	100

 

Variants and ordering information

The TX2 transmitter and RX2 receiver are manufactured in several variants:

Supply voltage: 5V ( 4V to 6V TX2 & RX2)
3V ( 3V to 4V for RX2, 2.2V to 4V for TX2)

RX data rate: Slower version, 7kHz baseband BW, data rate up to 14kbps
Faster version, 20kHz baseband BW, data rate up to 40kbps
Very fast version, 91kHz baseband BW, data rate up to 160kbps

TX data rate: Faster version, 20kHz baseband BW, data rate up to 40kbps
Very fast version, 100kHz baseband BW, data rate up to 160kbps

The following are standard:

TX2-433-40-5V:	433.92 MHz , 5V TX , 10mW
TX2-433-160-5V:	433.92 MHz , 5V TX , 10mW
RX2-433-14-5V:	433.92 MHz , 5V RX , 14kbps
RX2-433-40-5V:	433.92 MHz , 5V RX , 40kbps
RX2-433-160-5V:	433.92 MHz , 5V RX , 160kbps

 

 

 

 

 

3V versions of the above are available and should be ordered with a -3V suffix on the part number. (e.g. RX2-433-14-3V is set-up for 3V to 4V operation).

Duty Cycle requirements

The duty cycle is defined as the ratio, expressed as a percentage, of the maximum transmitter "on" time on one or more carrier frequencies, relative to a one hour period. Where an acknowledgement message is required, the additional transmitter "on" time shall be included.

There is a 10% duty cycle restriction on 433.050-434.790 MHz band in most of the EU member states.

The TX2-433 is a RF module intended to be incorporated into a wide variety of applications and finished products, Radiometrix has no control over the end use of the TX2-433.The harmonised band 433.050 to 434.790 MHz as detailed in Annex 1 Band E of CEPT/ERC Recommendation 70-03 (which can be downloaded at http://www.ero.dk/scripts/docmanag98/dm.dll/QueryDoc?Cat=Recommendation)
has list of countries where Duty Cycle restriction apply.

Module users should, therefore, ensure that they comply with the stated Duty Cycle requirements of the version of CEPT/ERC Recommendation 70-03 in place at the time of incorporation of the TX2-433 into their product. It should be noted that the stated Duty Cycle must not be exceeded otherwise any approval granted for the TX2-433 will be invalidated.

Type Approval

TX2/RX2 is CE Certified by independent Notified Body according to the R&TTE Directive (1999/5/EC). They are verified to comply with Radio standard ETSI EN 300 220-3 and EMC standard ETSI EN 301 489-3 by UKAS accredited Test Laboratory.

OEMs incorporating the TX2/RX2 as a component part of their product are authorised by Radiometrix Ltd to quote our type approval provided that all conditions are complied with. Breaching any of these conditions will invalidate type approval.

Limitation of liability

The information furnished by Radiometrix Ltd is believed to be accurate and reliable. Radiometrix Ltd reserves the right to make changes or improvements in the design, specification or manufacture of its subassembly products without notice. Radiometrix Ltd does not assume any liability arising from the application or use of any product or circuit described herein, nor for any infringements of patents or other rights of third parties which may result from the use of its products. This data sheet neither states nor implies warranty of any kind, including fitness for any particular application. These radio devices may be subject to radio interference and may not function as intended if interference is present. We do NOT recommend their use for life critical applications.
The Intrastat commodity code for all our modules is: 8542 6000.

R&TTE Directive

After 7 April 2001 the manufacturer can only place finished product on the market under the provisions of the R&TTE Directive. Equipment within the scope of the R&TTE Directive may demonstrate compliance to the essential requirements specified in Article 3 of the Directive, as appropriate to the particular equipment.
Further details are available on The Office of Communications (Ofcom) web site:
Licensing policy manual