Hartcran House, 231 Kenton Lane, Harrow, Middlesex, HA3 8RP, England
Tel: +44 (0) 20 8909 9595, Fax: +44 (0) 20 8909 2233, www.radiometrix.com
BiM2/BiM3G
Issue 2, 7 March 2013
433 / 868MHz FM Data Transceiver
The BIM2/3G data radio module is a PLL
synthesiser
based miniature PCB
mounting UHF radio transceiver which
enable the simple implementation of a
wireless data link at up to 128 kbps at
distances up to 75 metres in-building
and 300 metres open ground.
Features
Data rates up to 128 kbps
Figure 1: BIM3G-869.85-64-5V
Usable range up to 300 m
Versions available on 433.92MHz, 434.42MHz, 868.30 or 869.85MHz
Fully screened
Low profile with small footprint
Designed for compliance with EN 300 220-3 (radio) and EN 301 489-3 (EMC) standards
Available for operation at 433.05-434.79MHz, 868-870MHz band in the UK and Europe, these modules
combine full screening with extensive internal filtering to ensure EMC compliance by minimising spurious
radiations and susceptibilities. The BIM2/3G module will suit one-to-one and multi-node wireless links in
applications. Because of their small size and low power requirements, the module is ideal for use in portable,
battery-powered applications such as hand-held terminals.
Applications
Data loggers
EPOS equipment, barcode scanners, belt clip printers
Audience response systems
In-building environmental monitoring and control
Security and fire alarms
Restaurant ordering systems
Vehicle data up/download
Technical Summary
Crystal-locked PLL, FM modulated at up to 128 Kbps
+10dBm on 433.92MHz and 869MHz (Dependent on version)
High efficiency, >30%, DC to RF
2nd harmonic, > -60dBc
Single conversion FM superhet receiver
SAW front end filter gives >50dB image rejection
Sensitivity: -102dBm sensitivity @ 1ppm BER, 64kbps version
-108dBm sensitivity @ 1ppm BER, 15kbps version
TBA dBm sensitivity @ 1ppm BER, 128kbps version
RSSI output with 60dB range
Extremely low LO leakage, -125dBm typical
Supply: +5V (± 10%)
Current consumption: 10mA (typ.)
Size: 33 x 23 x 5mm
Evaluation platforms:
Universal Evaluation Kit, NBEK + DIL carrier
Radiometrix Ltd, BIM2/3G Data Sheet
page 1
Functional overview
The transmit section of the BiM2/3G consists of a frequency modulated crystal locked PLL feeding a buffer
amplifier and RF filter. A Tx select line controls operation. The transmitter 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 5V (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 is filtered to ensure compliance with the appropriate regulations and fed via a Tx/Rx
changeover switch to the antenna pin.
The receive section 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. A received signal strength (RSSI) output with 60dB of
range is provided. A version of BiM2/3G 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.
side view (through can)
5 mm
side view (with can)
top view (without can)
RF GND 1
Antenna 2
RF GND 3
4
5
No pin
6
7
8
0V 9
30.48 mm
33 mm
18 0V
17 Vcc
16 RX SELECT
15 TX SELECT
14 TXD
13 AF
12 RXD
11 RSSI/CD
10 0V
23 mm
recommended PCB hole size: 1.2 mm
module footprint size: 25 x 32 mm
pin pitch: 2.54 mm (0.1")
pins 4, 5, 6, 7 & 8 are not fitted
Fig. 2: Physical dimensions
Pin description
RF GND
pins 1 & 3
RF ground pins, internally connected to the module screen and to pins 9, 10 & 18 (0V). These pins should be
connected directly to the RF return path (e.g. coax braid, main PCB ground plane etc).
Antenna
pin 2
50 RF connection to the antenna, DC-isolated. See pages 7 & 8 for details of suitable antennas and feeds.
0V (GND)
pins 9, 10 & 18
Supply ground connection and screen.
RSSI /CD
pin 11
RSSI variant:
Received Signal Strength Indicator with 60dB range, operational when Rx is enabled. Output
voltage nominally 0.50Vdc (no signal), 1.0Vdc (maximum strength). See page.6 for typical characteristics.
Carrier Detect variant:
When the receiver is enabled, a low indicates a signal above the detection threshold is
being received. The output is high impedance and should only be used to drive a CMOS logic input.
Radiometrix Ltd, BIM2/3G Data Sheet
page 2
RXD
pin 12
Digital output from internal data slicer. The output is a squared version of the signal on pin 13 (AF) and may be
used to drive a decoder directly. The data is true data, i.e. as fed to the transmitter. Output is “open-collector”
format with internal 10k pullup to Vcc (pin 17).
AF
pin 13
Buffered & filtered analogue output from FM demodulator. Standing DC bias of 1V approx. Useful for test
purposes or for driving external decoders. External load should be >10k // <100pF
TXD
pin 14
This DC-coupled transmitter modulation input will accept either serial digital data or high level linear signals.
Drive signal must be limited to 0V min, 5V max. See page 7 for suggested drive methods. Input impedance
>50k.
TX select
pin 15
Active-low Transmit select. 47k internal pull-up to Vcc.
RX select
pin 16
Active-low Receive select. 47k internal pull-up to Vcc.
Pin 15 TX
Pin 16 RX
Function
1
1
Power down (<10A)
1
0
Receiver enabled
0
1
Transmitter enabled
0
0
Self test loop-back*
* Loop-back allows the receiver to monitor the transmitted signal. Under these conditions the Tx radiated signal
level will be reduced to approximately -10dBm).
Vcc
pin 17
+5V DC +ve supply pin. The supply should be clean, <20mVP-P ripple.
Radiometrix Ltd, BIM2/3G Data Sheet
page 3
Absolute maximum ratings
Exceeding the values below may cause permanent damage to the module.
Operating temperature
Storage temperature
Vcc (pin 17)
TX, RX select (pins 15, 16)
All other pins
Antenna (pin 2)
-20°C to +70°C
-40°C to +100°C
-0.3V to +16V(Dependant on version)
-9V to +5.5V
-0.3V to +Vcc
±50V DC, +10dBm RF
Performance specifications
Figures apply to standard version @ Vcc=5.0V, temperature +20°C, unless stated.
General
Supply voltage
Tx supply current
Rx supply current
RF centre frequency
Antenna port impedance
TX & RX select: high
(deselect)
low
(select)
Internal select pull-ups
Balanced code bit rate
Balanced code bit rate
Balanced code bit rate
Transmitter section
RF power output
TX harmonics/spurious emission
Initial centre frequency accuracy
FM deviation
Modulation bandwidth
Modulation distortion
TX spectral bandwidth @-40dBc
TXD input level: high
low
TX power up to full RF
Receiver section
RF sensitivity, 10dB S/N
RF sensitivity, 1ppm BER
RF sensitivity, 1ppm BER
RF sensitivity, 1ppm BER
RSSI range
IF bandwidth
Image rejection (f
RF
-21.4MHz)
IF rejection (10.7MHz)
Local osc. leakage, conducted
Baseband bandwidth @ -3dB
Baseband bandwidth @ -3dB
Baseband bandwidth @ -3dB
AF output signal level
DC offset on AF output
Distortion on recovered AF
Load capacitance, AF & RXD
Radiometrix Ltd, BIM2/3G Data Sheet
pin
17
17
17
-
2
15, 16
15, 16
15,16
12
12
12
pin
2
2
-
-
-
-
2
14
14
2
pin
2, 13
2, 12
2, 12
2, 12
2, 11
-
2
2
2
13
13
13
13
13
13
12, 13
min.
4.5
-
10
-
-
Vcc-0.5
0
-
-
-
-
min.
-
-
-10
±20
0
-
-
2.8
0
-
min.
-
-
-
-
-
-
50
100
-
0
0
0
200
1.5
-
-
typ.
5.0
14
11
50
max.
5.5
-
17
-
-
Vcc
0.5
-
128
64
15
max.
-
-40
+10
±35
65
10
250
0.2
1.5
max.
-
-
-
-
-
-
-
-
-110
65
50
7.8
350
2.5
5
100
units
V
mA
mA
MHz
V
V
k
kbps
kbps
kbps
units
dBm
dBm
kHz
kHz
kHz
%
kHz
V
V
ms
units
dBm
dBm
dBm
dBm
dB
kHz
dB
dB
dBm
kHz
kHz
kHz
mV p-p
V
%
pF
notes
Note 9
Note 9
Note 1
Note 9
Tx or Rx
47
-
-
-
typ.
+10
-55
0
±27
-
5
-
5
-
1
typ.
-113
-TBA
-102
-108
60
180
54
-
-125
-
-
-
250
2.0
1
-
To Vcc (pin 17)
-128 version
-64 version
-15 version
notes
Note 9
Peak
@ -3db
Note 2
worst case
Note 3
Note 3
Note 4
notes
-128 version
-64 version
-15 version
-128 version
-64 version
-15 version
Note 5
Note 6
Note 7
page 4
Receiver section
Dynamic Timing
Rx power up with signal present
Power up to valid RSSI, t
PU-RSSI
Power up to stable data, t
PU-data
Power up to stable data, t
PU-data
Power up to stable data, t
PU-data
Power up to stable data, t
PU-data
Power up to stable data, t
PU-data
Signal applied with Rx on
RSSI response time (rise/fall)
Signal to stable data, t
sig-data
Signal to stable data, t
sig-data
Signal to stable data, t
sig-data
Signal to stable data, t
sig-data
Signal to stable data, t
sig-data
Time between data transitions
Time between data transitions
Averaged code mark:space
Note:
pin
min.
typ.
max.
units
notes
11
12
12
12
12
12
-
-
-
-
-
-
0.5
2
10
2
10
3
1
10
10
ms
ms
ms
ms
ms
-15 version
-15-DS version
-64 version
-64-DS version
-128 version
11
12
12
12
12
12
14
14
14
-
-
-
-
-
-
70
15.6
20
0.1
0.5
5
0.2
1.5
0.75
-
-
50
-
1
0.5
5000
1500
80
ms
ms
ms
ms
ms
ms
s
s
%
-15 version
-15-DS version
-64 version
-64-DS version
-128 version
-15 version
-64 version
Note 8
1. Increases at high RF input level (>-20dBm)
2. See page 6 for further details
3. For specified FM deviation
4. Tx select low > full RF output
5. ±30kHz FM deviation –15 and –64 versions on;y
6. Min/max at ±50kHz offset
7. Max at ±50kHz offset
8. Average, at max. data rate
9. Dependant on version
Power supply requirement
The power supply ripple/noise should be below 10mVp-p to avoid problems. If the quality of the supply is in
doubt, it is recommended that a 10F low-ESR tantalum or similar capacitor be added between the module
supply pin (Vcc) and ground, together with a 10 series feed resistor between the Vcc pin and the supply rail.
The BIM2/3G incorporates a low voltage shutoff circuit, which prevents any possibility of erratic operation by
disabling the RF output of the transmitter if the supply voltage drops below 2.2V (±5%). This feature is self-
resetting, i.e. restoring the supply to greater than 2.2V will immediately restore full RF output from the module.
The standard BiM2/3G requires a regulated 5V supply with ripple content <100mVpk-pk.
Received Signal Strength Indicator (RSSI)
The BIM2/3G module incorporates a wide range RSSI which measures the strength of an incoming signal over
a range of approximately 60dB. This allows assessment of link quality and available margin and is useful when
performing range tests.
Please note that the actual RSSI voltage at any given RF input level varies somewhat between units. The RSSI
facility is intended as a relative indicator only - it is not designed to be, or suitable as, an accurate and
repeatable measure of absolute signal level or transmitter-receiver distance.
The output on pin 5 of the module has a standing DC bias in the region of 0.5V with no signal, rising to around
1V at maximum indication. The RSSI output source impedance is high (~100k) and external loading should
therefore be kept to a minimum.
To ensure a fast response the RSSI has limited internal decoupling of 1nF to ground. This may result in a small
amount of ripple on the DC output at pin 5 of the module. If this is a problem further decoupling may be added
at the expense of response speed, in the form of a capacitor from pin 5 to ground. For example, adding 10nF
here will increase RSSI response time from 100µs to around 1ms. The value of this capacitor may be increased
without limit.
Radiometrix Ltd, BIM2/3G Data Sheet
page 5
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