Receiver section
pin
min.
typ.
max.
units
notes
Dynamic Timing
Rx power up with signal present
Power up to valid RSSI, tPU-RSSI
Power up to stable data, tPU-data
Power up to stable data, tPU-data
11
12
12
-
-
-
0.5
2
2
1
10
10
ms
ms
ms
-15 version
-64 version
Signal applied with Rx on
RSSI response time (rise/fall)
Signal to stable data, tsig-data
Signal to stable data, tsig-data
11
12
12
-
-
-
100
0.5
0.2
-
1
0.5
µs
ms
ms
-15 version
-64 version
Time between data transitions
Time between data transitions
Averaged code mark:space
14
14
14
70
15.6
20
-
-
50
5000
1500
80
-15 version
-64 version
Note 8
µs
µs
%
Note: 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 10µF low-ESR tantalum or similar capacitor be added between the module
supply pin (Vcc) and ground, together with a 10Ω 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 (~100kΩ) 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
RADIOMETRIX [ RADIOMETRIX LTD ]
