BiM3B

Features:

Complies with European harmonised standards EN 300 220 and EN 301 489
869.85MHz 5mW 100% duty cycle or 868.30MHz 25mW 1% duty cycle
RF power output +14dBm (25mW) on 868.30MHz
+7dBm (5mW) on 869.85MHz
Data rates up to 64kbps
Crystal controlled PLL FM circuitry for both Tx and Rx
SAW front end filter and full screening
Receiver Sensitivity: -101dBm for 1ppm BER (64kbps)
-104dBm for 1ppm BER (10kbps)
Supply: 2.9V - 16V @ 35mA Tx (25mW), 17mA TX (5mW), 11mA Rx
Usable range up to 300 metres external, 75 metres in building
SAW front end filter and full screening
RSSI (standard) or carrier detect option
Analogue and digital baseband
Low profile with small footprint
33 x 23 x 5mm




Application

PDAs, organisers and laptops
Handheld terminals
EPOS equipment, barcode scanners, belt clip printers
Data loggers
Audience response systems
In-building environmental monitoring and control
Security and fire alarms
Restaurant ordering systems
Vehicle data up/download




Specifications

Operating temperature .........................-20°C to +70°C
Storage temperature ............................-40°C to +100°C
Vcc (pin 17) ...........................................-0.3V to +16V
TX, RX select (pins 15, 16) ....................-9V to +16V
All other pins ........................................-0.3V to +Vcc
Antenna (pin 2) ....................................±50V DC, +10dBm RF




Description

The transmit section of the BiM3B consists of a frequency modulated crystal locked PLL feeding a buffer amplifier and RF filter. A Tx select line controls operation. The transmitter BiM3B achieves full RF output typically within 1ms of this line being pulled low. Modulation is applied at the TXD input and may be either a serial digital stream toggling between 0V and 3V (digital drive) or a high level analogue waveform with the same peak limits (linear drive). Modulation shaping is performed internally by a 2nd order lowpass filter, which minimises spectral spreading. The RF output of BiM3B is filtered to ensure compliance with the appropriate regulations and fed via a Tx/Rx changeover switch to the antenna pin.

The receive section of BiM3B is a single conversion FM superhet with an IF of 10.7MHz. A SAW bandpass filter in the receiver front-end provides image rejection and suppression of other unwanted out-of-band signals. Like the transmitter, the receiver is controlled by its own active low RX select line. A post-detection lowpass filter establishes the signal bandwidth and ensures clean operation of the subsequent adaptive data slicer. The slicer is optimised for balanced data such as bi-phase code. The standard module BiM3B features a received signal strength (RSSI) output with 60dB of range. A version of BiM3B featuring a fast acting Carrier Detect (CD) output on the same RSSI pin is also available. The CD output will indicate the presence of any RF signals on the carrier frequency.