© Radiometrix Ltd

The BiM2 transceiver is an enhanced replacement for our original BiM. It offers greater transmit power, higher data rates, greatly improved receiver interference rejection and a lower profile.The module is ideal for enabling bi-directional wireless connectivity in battery powered or hand held applications. Figure 1: BiM2-433-160

Features CE Certified by independent Notified Body according to the R&TTE Directive (1999/5/EC) Verified to comply with Radio standard ETSI EN 300 220-3 by UKAS accredited Test Laboratory Verified to comply with EMC standard ETSI EN 301 489-3 by UKAS accredited Test Laboratory Usable range to 200 metres external, 50 metres in building Data rates up to160kbps SAW controlled 10mW FM transmitter Double conversion FM superhet receiver SAW front end filter and full screening Plug in replacement for Radiometrix BiM-433-30 3.3V or 5Volt supply at < 20mA

The BiM2 is a half duplex radio transceiver module for use in high-speed bi-directional data transfer applications at ranges up to 200metres. The module operates on the European licence exempt frequency of 433.92MHz and conforms to the relevant sections of EN 300 220-3 and EN 301 489-3. The small footprint of 23 x 33mm and low profile of 4mm together with low power requirements of <20mA @ 3 to 5 Volts enable convenient PCB installation. The high raw data rate capability of 64kbit/s and fast state change times will support high data throughput in ‘streaming’ applications or alternatively allows very short air time utilization (TX on < 10 ms) in multi-node scanning networks.

Applications PDA’s, organizers and laptops Handheld terminals EPOS equipment, barcode scanners, belt clip printers Data loggers Audience response systems In Building environmental monitoring and control High end security and fire alarms Restaurant ordering systems Vehicle data up/download

Technical Summary Size: 33 x 23 x 4mm Operating frequency: 433.92MHz Transmit power: 10dBm (10mW) nominal Supply: 5V, 3.3V Current consumption: 14mA transmit, 18mA receive Data bit rate: 64kbps max. (standard module) 64kbps, -93dBm sensitivity (for 1ppm BER)

Figure 2: BiM2 block diagram

Functional overview The transmit section of the BiM2 comprises of a SAW stabilized and FM modulated 433.92MHz oscillator feeding a 10mW buffer/output stage. Operation is controlled by a TX select line, the output achieving full power within 100ms of this line being pulled low. Modulation is applied at the TXD input and may be either a serial digital stream at the same levels as the module's supply rails (digital drive) or a high level analogue waveform with a pk to pk amplitude close to the modules supply level (linear drive). Modulation shaping is performed internally by a 2nd order 44kHz LPF to minimize spectral spreading. The RF output is filtered to meet the requirements of EN 300 220-3 and fed via a fast antenna changeover switch to the 50W antenna pin. The receive section of the BiM2 is a double conversion FM superhet with IF’s of 16MHz and 150kHz. The dual gate MOSFET LNA is followed by a 750kHz bandwidth SAW filter to provide >60 dB’s rejection of all out of band signals. The receiver is controlled by an active low select line and will power up in <1ms. A post-detection 2nd order 35kHz LPF establishes the signal bandwidth and ensures the clean operation of the subsequent adaptive data slicer. The slicer has a 2ms averaging time constant and is optimised for balanced data, e.g. bi-phase codes. A fast acting carrier detect output will indicate the presence of any RF signals

User interface Figure 3: BiM2 pin-out and dimension

Pin description: RF GND     pin 1 & 3 RF ground pin, internally connected to the module screen and pin 5, 9, 10, 18 (0 Volt). This pin should be connected to the RF return path (e.g. coax braid, main PCB ground plane etc.) Antenna      pin 2 50W RF input from the antenna, it is DC isolated internally. (see antenna for suggested antenna/feeds). 0Volt      pins 5, 9, 10, 18 Supply ground connection and screen. CD      pin 11 Carrier Detect - When the receiver is enabled, a low indicates a signal above the detection threshold is being received. The output is high impedance (50kW) and should only be used to drive a CMOS logic input. RXD      pin 12 This digital output from the internal data slicer is a squared version of the signal on pin 13 (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 AF    pin 13 This is a buffered and filtered analogue output from the FM demodulator. It has a standing DC bias of 1.2 volts and 400mV P-P base band signal. It is useful as a test point or to drive linear decoders. Load impedance should be >2kW and <100pF. TXD     pin 14 This DC coupled modulation input will accept either serial digital data (0V to Vcc levels) or High level linear signals. Input impedance is 10kW. TX select     pin 15 Active low transmit select. 10kW internal pull up to Vcc. RX select     pin 16 Active low receive select. 10kW internal pull up to Vcc. Pn 15 TX Pin16 RX Function 1 1 power down (<1mA) 1 0 receiver enabled 0 1 transmitter enabled 0 0 self test loop back Note: Loop test allows the receivers to monitor the transmitted signal. The receiver will not receive  external signals whilst the TX of the module is enabled. Vcc    pin 17 +ve supply pin.  +3.0 to +5.5 Volts @ <20mA . The supply must be clean < 20mVP-P ripple. A 2.2mF de-coupling capacitor and 10W series resistor are used internally to filter the supply.

Absolute maximum ratings Exceeding the values given below may cause permanent damage to the module. Operating temperature: -10°C to +60°C Extended operation at Reduced specification:  -20°C to + 70°C Storage temperature: -40°C to +100°C Vcc (pin 17): -0.1V to +10.0V Antenna (pin 2): ±50V @ <10MHz, +20dBm @ >10MHz All other pins: -0.1V to +Vcc + 0.6V Note: Operation of the BiM2 above 5.5 volt with efficient antenna may result in radiated power levels   above the licensed power level.  (Vcc = 5.0V / temperature = 20°C unless stated)

Electrical performance pin min. typ. max. units notes DC supply Supply voltage, Vcc (std. version) 17 4.0 5 5.5 V Supply voltage, Vcc (3V version) 17 3.3 3.3 4.0 V TX Supply current, Vcc (std.) 17 10 14 16 mV TX Supply current, Vcc(3.3V) 17 6 8 10 mA RX Supply current, Vcc (std.) 17 12 18 21 mA RX Supply current, Vcc (3.3V) 17 10 14 17 mA Supply ripple allowed 17 - - 20 mVpk-pk <1MHz Load capacitance on AF / RXD 12, 13 - - 100 pF CD output load resistnace 11 220 - - kW     Interface levels   data output high, 100mA source 12 - Vcc-0.6 - V RXD high data output low, 100mA sink 12 - 0.4 - V RXD low   TX & RX select, high (deselect 15, 16 Vcc-0.5 - Vcc V                              low (select) 15,16 0 - 0.5 V Intrenal selct pull-ups 15, 16 - 10 - kW              TXD, high 14 Vcc-0.5 Vcc V                        low 14 0 0.5 V   RF parameters pin min. typ. max. units notes Antenna pin impedance 2 - 50 - W TX or RX RF centre frequency - - 433.92 - MHz   Transmitter RF power output, Vcc std 2 +7 +10 +12 dBm 5V RF power output, Vcc 3.3V 2 +3 +6 +8 dBm 3.3V Initial frequency accuracy - -50 0 +50 kHz Overall frequency accuracy - -100 0 +100 kHz FM deviation (peak) - 20 30 40 kHz   Baseband Modulation bandwidth @ -3dB std - DC - 32 kHz Modulation bandwidth @ -3dB - DC - 80 kHZ 160kbps Modulation distortion (THD) - - - 15 %   Receiver RF/IF RF sensitivity @ 10dB SINAD 2, 13 -95 -101 - dBm RF sensitivity @ 10dB SINAD 2, 13 -91 -96 - dBm 3.3V RF sensitivity @ 10dB SINAD 2, 13 - -94 - dBm 160kbps RF sensitivity @ 1ppm BER 2, 12 -87 -93 - dBm 5V RF sensitivity @ 1ppm BER 2, 12 -82 -88 - dBm 3.3V RF sensitivity @ 1ppm BER 2, 12 - -90 - dBm 160kbps CD threshold, Vcc=5V 2, 11 -98 -104 - dBm note 2 CD threshold, Vcc=5V 2, 11 -92 -98 - dBm note 2 CD threshold, Vcc=5V 2, 11 - -96 - dBm note 2 IF bandwidth, Vcc=5V, 160kbps - - 500 - kHz CD bandwidth 2, 11 - 400 - kHz note 2 Ultimate (S+N)/N, -70dBm input 13 - >40 - dB Ultimate (S+N)/N, -70dBm input 13 - 30 - dB 160kbps maximum operating RF input 2 - +10 - dBm AF output level 13 - 400 - mV pk to pk DC offset on AF out 13 1.0 1.25 1.5 V Initial frequency accuracy - -50 0 +50 kHz CD centre     EMC parameters pin min. typ. max. units notes Rejection: rejection figures are relative to a 15dB (S+N)/N wanted signal. Co-channel rejection 2 - -10 - dB Image rejection (fRF - 2fIF) 2 - 64 - dB 402.0MHz Out of band rejection 2 - >70 - dB DC to 2GHz AM rejection 2 - >30 - dB Out of band blocking level 2 >-15 - dBm Out of band IP3 2 - +1 - dBm   Radiations LO leakage, conducted 2 - -60 -57 dBm   LO leakage, radiated - - -70 - dBm   TX 2nd harmonic 2 - -42 -36 dBm TX harmonics >1GHz 2 - -40 -30 dBm TX spectral bandwidth @ -40dBc 2 - - 250 kHz worst case   Baseband transfer performance pin min. typ. max. units notes TX—>RX Linear baseband BW @ -3dB 13 0.08 - 34 kHz TXD to AF Linear baseband BW @ -3dB, 160kbps 13 0.08 - 80 kHz TXD to AF Balance code bit rate 12 - 64 - kbps Time between code transitions 14 15.6 - 1000 ms Time between code transitions 14 15.6 - 120 ms 'S' version Time between code transitions 14 6.25 - 100 ms 160kbps Averaged code mark:space 14 30 50 70 % in any 2ms Preamble (01010101 pattern) duration 14 3 - - ms Link delay 14, 12 - 15 - ms   Dynamic timing Power up with signal present Power up to valid CD, tPU-CD 11 - 0.7 1 ms note 2 Power up to stable AF, tPU-AF 13 - 0.5 1 ms Power up to stable RXD output, tPU-RXD 12 - 3 5 ms Power up to stable RXD output, tPU-RXD 12 - - 1 ms 1, S version Power up to stable RXD output, tPU-RXD 12 - - 0.8 ms 160kbps   Signal applied with supply on Signal to valid CD, tsig-CD 11 - 0.25 0.5 ms note 2 Signal to stable RXD, tsig-RXD 12 - 3 4 ms Signal to stable RXD, tsig-RXD 12 - - 1 ms 1, S version Signal to stable RXD, tsig-RXD 12 - - 0.5 ms 160kbps   ms TX power up to full RF 2 - 100 - ms 8

Notes: 1. from 45% to 55% duty cycle 2. CD works reliably up to 40°C

Antennas The choice and positioning of transmitter and receiver antennas is of the utmost importance and is the single most significant factor in determining system range. The following notes are intended to assist the user in choosing the most effective antenna type for any given application. Integral antennas These are relatively inefficient compared to the larger externally-mounted types and hence tend to be effective only over limited ranges. They do however result in physically compact equipment and for this reason are often preferred for portable applications. Particular care is required with this type of antenna to achieve optimum results and the following should be taken into account: 1. Nearby conducting objects such as a PCB or battery can cause detuning or screening of the antenna which severely reduces efficiency. Ideally the antenna should stick out from the top of the product and be entirely in the clear, however this is often not desirable for practical/ergonomic reasons and a compromise may need to be reached. If an internal antenna must be used try to keep it away from other metal components and pay particular attention to the "hot" end (i.e. the far end) as this is generally the most susceptible to detuning. The space around the antenna is as important as the antenna itself. 2. Microprocessors and microcontrollers tend to radiate significant amounts of radio frequency hash which can cause desensitisation of the receiver if its antenna is in close proximity. The problem becomes worse as logic speeds increase, because fast logic edges generate harmonics across the VHF/UHF range which are then radiated effectively by the PCB tracking. In extreme cases system range may be reduced by a factor of 5 or more. To minimise any adverse effects situate antenna and module as far as possible from any such circuitry and keep PCB track lengths to the minimum possible. A ground plane can be highly effective in cutting radiated interference and its use is strongly recommended.

The following types of integral antenna are in common use: Quarter-wave whip: This is a wire, rod ,PCB track or combination connected directly to pin 2 of the module. Optimum total length is 16cm (1/4 wave @ 433MHz) 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 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. 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. Integral antenna summary: whip helical loop Ultimate performance *** ** * Ease of design set-up *** ** * Size * *** ** Immunity to proximity effects ** * ***

Figure 6: integral antenna configurations

External antennas These have several advantages if portability is not an issue, and are essential for long range links. External antennas can be optimised for individual circumstances and may be mounted in relatively good RF locations away from sources of interference, being connected to the equipment by coax feeder. Helical: Of similar dimensions and performance to the integral type mentioned above, commercially-available helical antennas normally have the coil element protected by a plastic moulding or sleeve and incorporate a coax connector at one end (usually a straight or right-angle BNC type). These are compact and simple to use as they come pre-tuned for a given application, but are relatively inefficient and are best suited to shorter ranges. Quarter-wave whip: Again similar to the integral type, the element usually consists of a stainless steel rod or a wire contained within a semi-flexible moulded plastic jacket. Various mounting options are available, from a simple BNC connector to wall brackets, through-panel fixings and magnetic mounts for temporary attachment to steel surfaces. A significant improvement in performance is obtainable if the whip is used in conjunction with a metal ground plane. For best results this should extend all round the base of the whip out to a 1/4 wave length radius (under these conditions performance approaches that of a half-wave dipole) but even relatively small metal areas will produce a worthwhile improvement over the whip alone. The ground plane should be electrically connected to the coax outer at the base of the whip. Magnetic mounts are slightly different in that they rely on capacitance between the mount and the metal surface to achieve the same result.

A ground plane can also be simulated by using 3 or 4 quarter-wave radials equally spaced around the base of the whip, connected at their inner ends to the outer of the coax feed. A better match to a 50W coax feed can be achieved if the elements are angled downwards at approximately 30-40° to the horizontal.

Fig. 7: Quarter wave antenna / ground plane configurations

Half-wave: There are two main variants of this antenna, both of which are very effective and are recommended where long range and all-round coverage are required: 1. The half-wave dipole consists of two quarter-wave whips mounted in line vertically and fed in the centre with coaxial cable. The bottom whip takes the place of the ground plane described previously. A variant is available using a helical instead of a whip for the lower element, giving similar performance with reduced overall length. This antenna is suitable for mounting on walls etc. but for best results should be kept well clear of surrounding conductive objects and structures (ideally >1m separation). 2. The end-fed half wave is the same length as the dipole but consists of a single rod or whip fed at the bottom via a matching network. Mounting options are similar to those for the quarter-wave whip. A ground plane is sometimes used but is not essential. The end-fed arrangement is often preferred over the centre-fed dipole because it is easier to mount in the clear and above surrounding obstructions. Yagi: This antenna consists of two or more elements mounted parallel to each other on a central boom. It is directional and exhibits gain but tends to be large and unwieldy - for these reasons the yagi is the ideal choice for links over fixed paths where maximum range is desired. Please note: Using a Yagi or other gain antenna with the BiM2 will exceed the maximum radiated power permitted by UK/European type approval regulations.

Module mounting considerations Good RF layout practice should be observed. If the connection between module and antenna is more than about 20mm long use 50W microstrip line or coax or a combination of both. It is desirable (but not essential) to fill all unused PCB area around the module with ground plane.

Variants and ordering information The standard BiM2, order code: BiM2-433-64 is supplied with pins fitted for operation on 5 volt supplies (4 to 5.5v): Following are the standard variants:

BiM2-433-64-3V A 3 volt version is available, for operation at 3.3volts (3.3 to 4.0 V) it is identical to the standard version but has been tested and aligned for operation at 3.3V. BiM2-433-64-S This is intended for RPC or Manchester code only and has fast settling time (maximum 1ms) BiM2-433-160-5V This is a fast version of the BiM2. Also available for operation at 3.3V supply (BiM2-433-160-3V). Additionally, for volume orders, Radiometrix can supply the BiM2 to the customers' PCB pin requirements or even without any pins.

Type Approval

BiM2 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.

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