Radiometrix
Hartcran House, 231 Kenton Lane, Harrow, HA3 8RP, England
Issue 1, 01 November 2004
Tel: +44 (0) 20 8909 9595, Fax: +44 (0) 20 8909 2233
TX3A & RX3A
UHF FM Data Transmitter and Receiver Modules
European versions: TX3A-869-64/RX3A-869-xx
USA versions:
TX3A-914-64/RX3A-914-xx
Data speed options (-xx) : -10 (10kbps), -64 (64kbps)
The TX3A & RX3A are miniature UHF
radio transmitter & receiver modules
designed
for
PCB
mounting.
They
facilitate the simple implementation of
data links at speeds up to 64kbps and
distances up to 75m in-building or 300m
over open ground.
TX3A Transmitter
RX3A Receiver
Features:
Frequencies available as standard: 869.85MHz, 914.5MHz
CE certified by independent Notified Body
Verified to comply with Radio standard EN 300 220-3 by accredited Test Laboratory
Verified to comply with EMC standard EN 301 489-3 by accredited Test Laboratory
North American version conforms to FCC part 15.249
Data rates up to 64kbps
Fully screened
Available for operation in the 868-870MHz band in Europe and the 902–928MHz band in
North America, both modules combine full screening with internal filtering to ensure EMC
compliance by minimising spurious radiation and susceptibility. The TX3A & RX3A will suit
one-to-one and multi-node wireless links in such applications as car and building security,
EPOS and inventory tracking, remote industrial process monitoring and data networks.
Because of their small size and low power requirements, both modules are ideal for use in
portable, battery-powered applications such as hand-held terminals.
Transmitter – TX3A
Crystal-locked PLL, FM modulated at up to 64 kb/s
Operation from 2.2V to 16V @ 7.5mA
Built-in regulator for improved stability and supply noise rejection
1mW nominal RF output
Enable facility
Receiver – RX3A
Single conversion FM superhet with SAW front end filter
Operation from 2.7V to 16V @ 11mA
Built-in regulator for improved stability and supply noise rejection
-100dBm sensitivity @ 1ppm BER, 64kb/s version
-107dBm sensitivity @ 1ppm BER, 10kb/s version
RSSI output with 60dB range
Enable facility
Extremely low LO leakage, -120dBm typical
Radiometrix Ltd, TX3A & RX3A Data Sheet
page 1
Functional description
The TX3A transmitter module uses a frequency modulated crystal-locked PLL and operates
between 2.2V and 16V at a current of 7.5mA nominal. At 3V supply it delivers nominally
0dBm (1mW) RF output. The SIL style TX3A measures 32 x 12 x 3.8 mm, excluding pins.
The RX3A module is a single conversion FM superhet receiver capable of handling data rates
of up to 64kbps. It will operate from a supply of 2.7V to 16V and draws 11mA when receiving.
The RX3 features a fast power-up time for effective duty cycle power saving and a signal
strength (RSSI) output with 60dB of range. Full screening and a SAW front-end filter give
good immunity to interference. The SIL style RX3A measures 48 x 17.5 x 4.5 mm, excluding
pins.
TX3A transmitter
supply
regulator
5
2.2 -- 12V
2
RF out
868/915 MHz
band pass
filter
buffer
VCO
÷
64
Loop
Filter
φ
4
En
ref
osc
35kHz
LPF
7
TXD
3
RF gnd
1
6
0V
Pin description
RF GND
(pins 1&3)
RF ground, internally connected to the
module screen and pin 6 (0V). These
pins should be directly connected to the
RF return path - e.g. coax braid, main
PCB ground plane etc.
RF OUT
(pin 2)
50Ω RF output to the antenna.
Internally DC-isolated. See antenna
section of apps notes for details of
suitable antennas.
En
(pin 4)
Tx enable. <0.15V shuts down module
(current <1µA). >1.7V enables the
transmitter. Impedance ~1MΩ. Observe
slew rate requirements (see apps notes).
Fig 1 :TX3A block diagram
32 mm
3.8 mm
12.0
mm
12.5
mm
TX3A
Radiometrix
PCB level
15.24 mm
1
2
3
4
5
6
7
1 = RF GND
2 = RF OUT
3 = RF GND
4 = En
5 = Vcc
6 = 0V
7 = TXD
7 holes, 0.7 mm dia, pin spacing 2.54 mm
Fig2: TX3A physical dimensions
(pin 5)
Vcc
+2.2V to +16V DC supply. Max ripple content 0.1V
P-P
. Decoupling is not generally required.
0V
(pin 6)
DC supply ground. Internally connected to pins 1 & 3 and module screen.
TXD
(pin 7)
DC-coupled modulation input. Accepts serial digital data at 0V to 2.5V levels.
See applications notes for suggested drive methods. Input is high impedance (>100kΩ).
Radiometrix Ltd, TX3A & RX3A Data Sheet
page 2
RX3A receiver
869/914MHz
SAW BPF
LNA 1
1
RF in
LNA 2
MIXER
IF1
10.7MHz
10.7MHz IF filter
IF2/Lim
10.7MHz
5
RSSI
10.7MHz
ceramic
discriminator
f
RF
- 10.7MHz)
Audio LPF
AF
buffer
8
AF out
32
XTAL OSC.
VCO
C
L
R
T
C
T
data
slicer
10kΩ
7
V
cc
4
En
6
0V
9
RXD
Loop filter
Crystal
Phase
26/28MHz detector
(Fixed frequency PLL Osc.)
+2.8V
regulated
to circuit
Low
dropout
regulator
2, 3
RF gnd
Fig.3: RX3A block diagram
Pin description
RF IN
(pin 1)
50Ω RF input from antenna.
Internally DC-isolated. See
antenna section of applications
notes for suggested antennas and
feeds.
RF GND
(pins 2 & 3)
RF ground, internally connected to
the module screen and pin 6 (0V).
These pins should be connected to
the RF return path - e.g. coax
braid, main PCB ground plane etc.
En
(pin 4)
Rx enable. <0.15V shuts down
module (current <1µA). >1.7V enables
the receiver. Impedance ~1MΩ. Observe
slew rate requirements (see apps notes).
48 mm
4.5 mm
18.0 mm
17.5 mm
RX3A
25.4 mm
Radiometrix
PCB level
1
2
3
4
5
6
7
8
9
1 = RF IN
2 = RF GND
3 = RF GND
4 = En
5 = RSSI
6 = 0V
7 = Vcc
8 = AF out
9 = RXD
9 holes of 0.7 mm dia. pin spacing 2.54mm
Fig.4: RX3A physical dimensions
RSSI
(pin 5)
Received signal strength indicator with >65dB range. See applications notes for typical characteristics.
0V
(pin 6)
DC supply ground. Internally connected to pins 2 & 3 and module screen.
Vcc
(pin 7)
+2.7V to +16V DC supply. Max ripple content 0.1V
P-P
. Decoupling is not generally required.
AF out
(pin 8)
Buffered and filtered analogue output from the FM demodulator. Standing DC bias 1V approx. External
load should be >10kΩ // <100pF.
RXD
(pin 9)
Digital output from the internal data slicer. The data is true data, i.e. as fed to the transmitter.
Output is “open-collector” format with internal 10kΩ pull-up to Vcc (pin 7).
Radiometrix Ltd, TX3A & RX3A Data Sheet
page 3
Absolute maximum ratings
Exceeding the values given below may cause permanent damage to the module.
Operating temperature
Storage temperature
TX3A
Vcc (pin 5)
TXD (pin 7)
En (pin 4)
RF OUT (pin 2)
RX3A
Vcc, RXD (pins 7,9)
En (pins 4)
RSSI, AF (pins 5, 8)
RF IN (pin 1)
-20°C to +70°C
-40°C to +100°C
-0.3V to +16V
±7V
-0.3V to +Vcc V
±50V
DC, +10dBm RF
-0.3V to +16V
-0.3V to +Vcc V
-0.3V to +3V
±50V
DC, +10dBm RF
Performance specifications:
TX3A transmitter
(Vcc = 3.0V / temperature = 20
°
C unless stated)
pin
DC supply
Supply voltage
Supply current
RF
RF power output @ Vcc = 2.2V
RF power output @ Vcc
≥
2.8V
Harmonics / spurious emissions
Initial frequency accuracy
FM deviation (peak)
Baseband
Modulation bandwidth @ -3dB
Modulation distortion (THD)
TXD input level (logic low)
TXD input level (logic high)
Dynamic timing
Power-up time (En
→
full RF)
5
5
2
2
2
min.
2.2
typ.
3.0
7.5
-1
0
-55
0
±30
max.
16
9.5
units
V
mA
dBm
dBm
dBc
kHz
kHz
kHz
%
V
V
ms
notes
1,6
2
2
2
3
4
-25
-45
+25
0
7
7
-0.2
+2.3
5
0
+2.5
1.0
35
10
+0.2
+3
1.5
6
5,6
5,6
Notes:
1.
2.
3.
4.
5.
6.
RF output is automatically disabled below 2.2V supply voltage.
RF output terminated with 50Ω resistive load.
Meets or exceeds EN/FCC requirements at all frequencies.
With 0V – 2.5V modulation input.
To achieve specified FM deviation.
See applications information for further details.
Radiometrix Ltd, TX3A & RX3A Data Sheet
page 4
Performance specifications:
RX3A receiver
(Vcc = 3.0V / temperature = 20
°
C unless stated)
pin
DC supply
Supply voltage
Supply current
RF/IF
RF sensitivity
RF sensitivity
RF sensitivity
RF sensitivity
@
@
@
@
10dB (S+N)/N
10dB (S+N)/N
1ppm BER
1ppm BER
7
7
1,
1,
1,
1,
8
8
9
9
min.
2.7
10
typ.
5.0
11
-114
-107
-107
-100
-10
-120
60
180
50
-120
-110
7.8
50
400
1.75
10
100
max.
16
16
units
V
mA
dBm
dBm
dBm
dBm
dBm
dBm
dB
kHz
dB
dB
dBm
kHz
kHz
mV
P-P
V
%
dB
pF
10kbps
64kbps
2
3
3
notes
1
10kbps
64kbps
10kbps
64kbps
Max operational RF input
RSSI threshold
RSSI range
IF bandwidth
Image rejection
IF rejection (10.7MHz)
LO leakage, conducted
Baseband
Baseband bandwidth @ -3dB
Baseband bandwidth @ -3dB
AF level
DC offset on AF out
Distortion on recovered AF
Ultimate (S+N)/N
Load capacitance, AFout / RXD
Dynamic timing
Power up with signal present
Power up to valid RSSI
Power up to stable data
Power up to stable data
Signal applied with supply on
RSSI response time (rise/fall)
Signal to stable data
Signal to stable data
Time between data transitions
Time between data transitions
Mark : space ratio
1
1,5
1,5
1
1
1
8
8
8
8
8
8
8,9
40
100
0
0
200
0.3
300
1.0
1
40
4,5
4,9
4,9
1, 5
1, 9
1,9
9
9
9
0.1
15.6
20
1
10
5
100
5
5
30
10
ms
ms
ms
µs
ms
ms
µs
%
3, 10kbps
3, 64kbps
30
10
15
1500
80
3, 10kbps
3, 64kbps
4, 10kbps
4, 64kbps
5
50
Notes:
1. Current increases at higher RF input levels (-20dBm and above).
2. For received signal with
±30kHz
FM deviation.
3. Typical figures are for signal at centre frequency, max. figures are for
±50kHz
offset.
4. For 50:50 mark to space ratio (i.e. square wave).
5. Average over 30ms (10kbps version) or 3ms (64kbps version) at maximum data rate.
Radiometrix Ltd, TX3A & RX3A Data Sheet
page 5
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