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
LMT3
The LMT3 is a 25kHz channel narrowband
multichannel transmitter offering up to 25mW RF
power. LMT3 can be paired with the Category 1
compliant receiver intended for European 869.2-
869.25MHz Social Alarm application. It can also be
used for any 868 - 870MHz band Non-Specific SRD
applications. The module offers a low power,
reliable data link in an industry-standard pin out and
footprint.
Issue 1, 22 January 2013
NBFM Multi-channel transmitter for 868MHz SRD band
Figure 1: LMT3 transmitter
Features
Conforms to EN 300 220-3 and EN 301 489-3
PLL synthesizer with TCXO
Data rates up to 5 kbps for standard module
Usable range over 500m @ 25mW
Fully screened, Low profile
Low power requirements
Applications
Social Alarm
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
Social Alarm frequencies: CH0: 869.2125MHz, CH1: 869.2375MHz
Custom frequency within 865MHz - 870MHz
32 channels
Transmit power: +10dBm (10mW) / +14dBm (25mW)
Supply range: 3.1 – 15V (TX @ 10mW), 4.1 – 15V (TX @ 25mW)
Current consumption: 34mA @ 10mW, 68mA @ 25mW
Data bit rate: 5kbps max. (standard module)
Serial configuration by inverted RS232 at 3V CMOS level
Evaluation platforms:
NBEK + LM Series carrier
Matching receiver:
COR3-869-5
Radiometrix Ltd
LMT3 Data Sheet
page 1
Radiometrix Ltd
LMT3 Data Sheet
Figure 2: LMT3 block diagram
page 2
Figure 3: LMT3 footprint (top view)
Pin description –
LMT3
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 (@ 25mW)
Ground
Transmit Enable (active low)
DC coupled input for 3V CMOS logic. R
in
=47kΩ
Not present in LMT3
Parallel Channel select LSB
1
Serial frequency programming / configuration
Parallel Channel select
Parallel Channel select
Parallel Channel select MSB
Not present in LMT3
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.
Radiometrix Ltd
LMT3 Data Sheet
page 3
Serial interface commands
2400 baud RS232. 8 bit data, no parity, 1 start bit, 1 or 2 stop bits.
Serial data is sent to the unit on one of the parallel channel select pins (P0). It is very important that the unit
does not 'decode' switch bounce in ordinary operation as a command string, or spurious re-writing of the
e2prom will result. For this reason the user must send the 16 character string ENABLESERIALMODE
(followed by a carriage return) to activate the serial command mode before sending any of the command
strings listed below. Command mode is disabled on power down, or on reception of a # character. To
successfully program the unit, it must be enabled (TXE low).
GOCHAN aa
LOAD aa nnnnn
SETPAR
SETSER
RVALUE rrrr
SINGLE nnnnn
<cr>
/
#
Serially select channel aa, where aa is ch0 to ch31
Set value of N register for channel aa, where aa is Channels 0 to 31
Channel selected by 4 bit parallel inputs (ch0 to ch15 only)
Channel selected by most recent GOCHAN operation
Set value for R register
Set value of N for single channel operation.
N value NOT stored in EEPROM
Process entry
Clear all buffers
Disable command mode
aa = a two digit channel number from 00 to 31
nnnnn = synthesizer N register value (up to 65535)
rrrr = synthesizer R register value (up to 16383)
N
TX
=
f
RF
f
Channelspacing
Note:
=
869.200
MHz
=
34768
25
kHz
R
=
f
TCXO
f
channelspacing
=
13
MHz
, So R=520
25
kHz
A pause of at least 50ms must be allowed between command strings (EEPROM
programming time).
SINGLE mode does not store the N value in EEPROM. Therefore the unit is inoperative after
a power down until either another valid SINGLE command is received, or mode is changed
by a GOCHAN, SETPAR or SETSER command. SINGLE mode is intended for frequency
agile applications.
If an N value greater than 65535 is needed then an offset of +65536 can be selected by
setting bit 15 of the R value high (the N value is then reduced by 65536 of course)"
Example: Fout = 869.2125
Fcomp = 12.5KHz
N = 69537 This exceeds 65535, so:
Bit 15 of R is set : RVALUE 33808
65536 is subtracted: LOAD00 4001
Radiometrix Ltd
LMT3 Data Sheet
page 4
Condensed specifications
Frequency
Frequency stability
Channel spacing
Number of channels
Social Alarm (SAL) variant: CH0: 869.2125MHz, CH1: 869.2375MHz
User customisable frequencies: 865MHz – 870MHz
±1.5kHz
25kHz
16 channels controlled by parallel port
or 32 via RS232 interface
-10 ºC to +60 ºC (Storage -30 ºC to +70 ºC)
Compliant with ETSI EN 300 220-3 and EN 301 489-3
Operating temperature
Spurious radiations
Transmitter
Output power
Peak deviation
TX on switching time
Modulation type
TX modulation bandwidth
Adjacent channel TX power
TX spurious
Supply
Voltage
Current
+10dBm (10mW) ±1dB
+14dBm (25mW) ±1dB
±3kHz
30ms from TXE transition
FSK (F3D)
DC – 5kHz (3V CMOS compatible)
<-37dBm
<-45dBm (no RF output in Standby)
3.1V – 15V (10mW)
4.1 – 15V (25mW)
34mA @ 10mW (nominal)
68mA @ 25mW (nominal)
<5µA standby (TXE high or floating)
data (CMOS/TTL compatible)
33 x 23 x 9mm
10 (8) pin 0.1" pitch dual row (5+5) header
2pin 0.1” pitch
1.2mm
Inputs
Size
Interface
User
RF
Recommended PCB hole size
Ordering Information:
Part No.
LMT3-869.2125-5
LMT3-869-5-SAL
LMT3-869-5
LMT3-869-5-25mW
Frequency
(MHz)
869.2125
869.200 - 869.250
868 - 870
868 - 870
RF power
(mW)
10
10
10
25
Channel spacing
(kHz)
25
25
25
25
Data rate
(kbps)
5
5
5
5
Matching COR3 receiver
Part Number
COR3-869.2125-5-H
COR3-869-5-SAL
COR3-869-5-SAL-H
COR3-869-5
Frequency
869.2125MHz
869.2-869.25MHz
869.2-869.25MHz
868-870MHz
Module mounting
Horizontal Mounting,
Perpendicular pins
Vertical Mounting,
Parallel pins
Horizontal Mounting,
Perpendicular pins
Vertical Mounting,
Parallel pins
Pins
RF, RFGND, RSSI, GND, VCC, AF, RXD
RF, RFGND, RSSI, GND, VCC, AF, RXD
P0/PGM
RF, RFGND, RSSI, GND, VCC, AF, RXD
P0/PGM
RF, RFGND, RSSI, GND, VCC, AF, RXD
P3, P2, P1, P0/PGM
Radiometrix Ltd
LMT3 Data Sheet
page 5
电机控制
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
