EW
N
Radiometrix
Hartcran House, 231 Kenton Lane, Harrow, HA3 8RP, England
Tel: +44 (0) 20 8909 9595, Fax: +44 (0) 20 8909 2233
Issue 2, 01 November 2007
LMT2/LMR2
UHF Narrow Band FM Low Cost multi channel radio modules
The LMT2 transmitter and LMR2
receiver modules offer a multi channel,
low power, and reliable data link. This
makes the LMT2/LMR2 pair ideally
suited to those low power applications
where existing wideband modules have
insufficient range, or where low cost
multi-channel operation is needed
without
compromising
on
RF
specification or regulatory requirement.
Figure 1: LMT2 transmitter and LMR2 receiver
Features
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Conforms to EN 300 220-3 and EN 301 489-3
High performance double superhet. PLL synthesizer with TCXO
quasi-dc (peak sampling) data recovery circuit (for enhanced performance on unbalanced
datastreams)
SAW front-end filter
Data rates up to 5 kbps for standard module
Usable range over 1km
Fully screened. Low profile
Feature-rich interface (RSSI, analogue and digital baseband)
Re-programmable via RS232 interface
Low power requirements
Applications
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Handheld terminals
EPOS equipment, barcode scanners
Data loggers
Industrial telemetry and telecommand
In-building environmental monitoring and control
High-end security and fire alarms
DGPS systems
Vehicle data up/download
Heavy vehicle/machinery controls
Technical Summary
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Operating frequency: 433.875-434.650MHz (EU band)
458.525 - 459.1MHz (UK band)
Other custom UHF bands
32 channels
Transmit power: +10dBm (10mW) / +20dBm (100mW)
Supply range: 3.1 – 15V (TX @ 10mW and RX), 4.1 – 15V (TX @ 100mW)
Current consumption: 34mA @ 10mW, 90mA @ 100mW (transmit) and 20mA (receive)
Data bit rate: 5kbps max. (standard module)
Receiver sensitivity: -118dBm (for 12 dB SINAD)
Serial configuration by inverted RS232 at 3V CMOS level
LMT2/LMR2 Data Sheet
page 1
Radiometrix Ltd
Radiometrix Ltd
LMT2/LMR2 Data Sheet
Figure 2: LMT2 block diagram
page 2
Figure 3: LMT2 footpint (top view)
Pin description –
LMT2
Pin
1a
2a
3a
4a
5a
1b
2b
3b
4b
5b
Name
Vcc
0V
TXE
TXD
No pin
P0/PGM
P1
P2
P3
No pin
Function
3.1 – 15V power supply (@ 10mW)
4.1 – 15V power supply (@ 100mW)
Ground
Transmit Enable (active low)
DC coupled input for 3V CMOS logic. R
in
=47kΩ
Not present in LMT2
Parallel Channel select LSB
Serial frequency programming / configuration
1
Parallel Channel select
Parallel Channel select
Parallel Channel select MSB
Not present in LMT2
Notes:
1. Serial programming is by an inverted, CMOS logic level, 2400 baud RS232 datastream applied
to the P0 pin.
2. Channel select inputs have pullups (50kΩ) to 3v internal rail. Do not exceed 3V logic levels on
this port.
3. Channel select inputs are active low
4. TXE has a 100kΩ pullup to Vcc
5. All pins are on an 0.1" grid
6. The pins 5a/b are not present, but are included in footprint for compatibility with other units in
this family
7. In the 'off' state a PIN switch open circuits the RF output pin. There are no 'off' state spuri.
8. 10mW unit will operate (with marginally reduced specifications and lower (6-8mW) output
power) from a 3.0V rail. This must be well regulated and without noise or ripple, as in this state
the unit's internal regulator no longer operates, and provides no supply rejection.
9. 100mW versions should not be run continuously from supply voltages > 9v
Radiometrix Ltd
LMT2/LMR2 Data Sheet
page 3
Radiometrix Ltd
LMT2/LMR2 Data Sheet
Figure 4: LMR2 block diagram
page 4
Figure 5: LMR2 footpint (top view)
Pin description –
LMR2
Pin
1a
2a
3a
4a
5a
1b
2b
3b
4b
5b
Name
Vcc
0V
RXE
RXD
AF out
P0/PGM
P1
P2
P3
RSSI
Function
3.1 – 15V power supply
Ground
Receiver Enable (active high)
Data out (open collector, no pullup)
700mV p-p audio. DC coupled, approx 0.8v bias.`
Parallel Channel select LSB
Serial frequency programming / configuration
1
Parallel Channel select
Parallel Channel select
Parallel Channel select MSB
DC level between 0.5v and 2.2v. 60dB dynamic range
NOTES:
1. Serial programming is by an inverted, cmos logic level, 2400 baud RS232 datastream applied to
the P0 pin.
2. Channel select inputs have pullups (50kΩ) to 3v internal rail. Do not exceed 3v logic levels on
this port.
3.
Channel select inputs are active low
4.
All pins are on an 0.1" grid
5.
Data recovery circuit used for RXD is not a simple 'average and compare' type. It is a peak
sampling quasi-DC coupled design, allowing a greater than usual flexibility in data format.
6.
Unit will operate (with marginally reduced specifications) from a 3.0v rail. This must be well
regulated and without noise or ripple, as in this state the unit's internal regulator no longer
operates, and provides no supply rejection.
Radiometrix Ltd
LMT2/LMR2 Data Sheet
page 5
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