®
·
Designed for Short-Range Wireless Data Communications
·
Supports RF Data Transmission Rates Up to 115.2 kbps
·
3 V, Low Current Operation plus Sleep Mode
·
Stable, Easy to Use, Low External Parts Count
The TX5003 hybrid transmitter is ideal for short-range wireless data applications
where robust operation, small size, low power consumption and low cost are required.
All critical RF functions are contained in the hybrid, simplifying and speeding design-
in. The TX5003 includes provisions for both on-off keyed (OOK) and amplitude-shift
keyed (ASK) modulation. The TX5003 employs SAW filtering to suppress output har-
monics, facilitating compliance with FCC Part 15 and similar regulations.
TX5003
303.825 MHz
Hybrid
Transmitter
Absolute Maximum Ratings
Rating
Power Supply and All Input/Output Pins
Non-Operating Case Temperature
Soldering Temperature (10 seconds)
Electrical Characteristics
Characteristic
Operating Frequency
Modulation Types
OOK Data Rate
ASK Data Rate
Transmitter Performance
Peak RF Output Power, 250 µA TXMOD Current
Peak Current, 250 µA TXMOD Current
OOK Turn On/Turn Off Times
ASK Output Rise/Fall Times
2
nd
- 4
th
Harmonic Outputs
5
th
- 10
th
Harmonic Outputs
Non-harmonic Spurious Outputs
Sleep Mode Current
Sleep to Transmit Switch Time
Transmit to Sleep Switch Time
Control Input Logic Low Level
Control Input Logic High Level
Power Supply Voltage Range
Operating Ambient Temperature
V
CC
T
A
1
Vcc - 300
2.2
-40
3.7
+85
I
S
t
TOR
t
RTO
0.7
21
15
200
P
O
I
TP
t
ON
/t
OFF
t
TR
/t
TF
1.5
9.5
20/15
1.1/1.1
-50
-55
-50
dBm
mA
µs
µs
dBm
dBm
dBm
µA
µs
µs
mV
mV
Vdc
o
Value
-0.3 to +4.0
-50 to +100
250
Units
V
o
o
C
C
Sym
f
O
Notes
Minimum
303.625
Typical
Maximum
304.025
Units
MHz
OOK & ASK
10
115.2
kbps
kbps
C
1
T r a n s m itte r O O K C o n fig u r a tio n
T r a n s m itte r A S K C o n fig u r a tio n
C
R F B 2
+ 3
V D C
C
D C B
C
R F B 2
+ 3
V D C
C
D C B
+
+
T /S
1 9
1 8
C N T
R L 0
1 7
C N T
R L 1
1 6
V C C
2
1 5
P
W ID T H
1 4
P
R A T E
1 3
T H L D
1
1 2
T H L D
2
R R E F
G N D 2
L P F
A D J
9
1 9
1 8
C N T
R L 0
T /S
1 7
C N T
R L 1
1 6
V C C
2
1 5
P
W ID T H
1 4
P
R A T E
1 3
T H L D
1
1 2
T H L D
2
R R E F
G N D 2
L P F
A D J
9
L
A T
2 0
G N D
3
R F IO
G N D 1
V C C
1
1
2
L
1 1
1 0
A T
T O P V IE W
A G C
C A P
3
P K
D E T
4
B B
O U T
5
C M P
IN
6
R X
D A T A
7
T X
M O D
8
2 0
G N D
3
R F IO
G N D 1
V C C
1
1
2
T O P V IE W
A G C
C A P
3
P K
D E T
4
B B
O U T
5
C M P
IN
6
R X
D A T A
7
T X
M O D
8
1 1
1 0
L
E S D
L
E S D
L
+ 3
V D C
R F B
L
C
R
R F B 1
T X M
R F B
M o d u la tio n In p u t
+ 3
V D C
C
R
R F B 1
T X M
M o d u la tio n In p u t
Transmitter Set-Up, 3.0 Vdc, -40 to +85
0
C
Item
Nominal NRZ Data Rate
Minimum Signal Pulse
Maximum Signal Pulse
TXMOD Resistor
DC Bypass Capacitor
RF Bypass Capacitor 1
RF Bypass Capacitor 2
RF Bypass Bead
Series Tuning Inductor
Shunt Tuning/ESD Inductor
Symbol
DR
NOM
SP
MIN
SP
MAX
R
TXM
C
DCB
C
RFB1
C
RFB2
L
RFB
L
AT
L
ESD
OOK
2.4
416.67
1666.68
8.2
4.7
27
100
Fair-Rite
82
33
ASK
19.2
52.08
208.32
8.2
4.7
27
100
Fair-Rite
82
33
ASK
115.2
8.68
34.72
8.2
4.7
27
100
Fair-Rite
82
33
Units
kbps
µs
µs
K
µF
pF
pF
vendor
nH
nH
Notes
see page 1
single bit
4 bits of
same value
±5%, for 1.5 dBm output
tantalum
±5% NPO
±5% NPO
2506033017YO or equivalent
50 ohm antenna
50 ohm antenna
CAUTION: Electrostatic Sensitive Device. Observe precautions when handling.
Notes:
1. Do not allow the voltage applied to a control input pin to exceed Vcc + 200 mV.
2. The companion receiver to the TX6000 is the RX6000. Please see RFM’s web site at www.rfm.com for details.
2
Transmitter Theory of Operation
Introduction
RFM’s TX-series hybrid transmitters are specifically designed for
short-range wireless data communication applications. These trans-
mitters provide robust operation, very small size, low power con-
sumption and low implementation cost. All critical RF functions are
contained in the hybrid, simplifying and speeding design-in. The
transmitters can be readily configured to support a wide range of
data rates and protocol requirements. TX-series transmitters feature
excellent suppression of output harmonics and virtually no other RF
emissions, making them easy to certify to short- range (unlicensed)
radio regulations.
Transmitter Block Diagram
Figure 1 is the general block diagram of the transmitter. Please refer
to Figure 1 for the following discussions.
Antenna Port
The only external RF components needed for the transmitter are the
antenna and its matching components. Antennas presenting an im-
pedance in the range of 35 to 72 ohms resistive can be satisfactorily
matched to the RFIO pin with a series matching coil and a shunt
matching/ESD protection coil. Other antenna impedances can be
matched using two or three components. For some impedances,
two inductors and a capacitor will be required. A DC path from RFIO
to ground is required for ESD protection.
Transmitter Chain
The transmitter chain consists of a SAW coupled-resonator oscilla-
tor followed by a modulated buffer amplifier. The SAW coupled res-
onator output filter suppresses transmitter harmonics to the
antenna.
Transmitter operation supports two modulation formats, on-off
keyed (OOK) modulation, and amplitude-shift keyed (ASK) modula-
tion. When OOK modulation is chosen, the transmitter output turns
completely off between “1” data pulses. When ASK modulation is
chosen, a “1” pulse is represented by a higher transmitted power
level, and a “0” is represented by a lower transmitted power level.
OOK modulation provides compatibility with first-generation ASH
technology, and provides for power conservation. ASK modulation
must be used for high data rates (data pulses less than 200 µs).
ASK modulation also reduces the effects of some types of interfer-
ence and allows the transmitted pulses to be shaped to control mod-
ulation bandwidth.
The modulation format is chosen by the state of the CNTRL0 and
the CNTRL1 mode control pins, as discussed below. In the OOK
mode, the oscillator amplifier TXA1 and buffer amplifier TXA2 are
turned off when the voltage to the TXMOD input falls below 220 mV.
In the OOK mode, the data rate is limited by the 20/15 µs turn-on
and turn-off time of the oscillator. In the ASK mode TXA1 is biased
ON continuously, and the output of TXA2 is modulated by the
TXMOD input current. Minimum output power occurs in the ASK
mode when the modulation driver sinks about 10 µA of current from
the TXMOD pin.
T r a n s m itte r B lo c k D ia g r a m
A n te n n a
S A W
C o u p le d
R e s o n a to r
S A W
C R
F ilte r
A n t
T u n e
T u n e /E S D
T X A 1
T X A 2
M o d u la tio n
& B ia s C o n tr o l
R
T X
IN
T X M
C N
T R L 1
C N
T R L 0
Figure 1
3
The transmitter RF output power is proportional to the input current
to the TXMOD pin. A series resistor is used to adjust the peak trans-
mitter output power. 0 dBm of output power requires about 250 µA
of input current.
Transmitter Mode Control
The three transmitter operating modes – transmit ASK, transmit
OOK, and power-down (sleep), are controlled by the Modulation &
Bias Control function, and are selected with the CNTRL1 and
CNTRL0 control pins. Setting CNTRL1 high and CNTRL0 low place
the unit in the ASK transmit mode. Setting CNTRL1 low and
CNTRL0 high place the unit in the OOK transmit mode. Setting
CNTRL1 and CNTRL0 both low place the unit in the power-down
mode. (Note that the resistor driving TXMOD must also be low in the
power-down mode to minimize power-down current.) CNTRL1 and
CNTRL0 are CMOS compatible inputs. These inputs must be held
at a logic level; they cannot be left unconnected.
Turn-On Timing
The maximum time required for either the OOK or ASK transmitter
mode to become operational is 5 ms after the supply voltage
reaches 2.2 Vdc. The total turn-on time to stable transmitter opera-
tion for a 10 ms power supply rise time is 15 ms.
Sleep and Wake-Up Timing
The maximum transition time from either transmit mode to the sleep
mode (t
TOS
and t
TAS
) is 15 µs after CNTRL1 and CNTRL0 are both
low (1 µs fall time).
The maximum time required to switch from the sleep mode to either
transmit mode (t
STO
and t
STA
) is 21 µs. Most of this time is due to the
start-up of the transmitter oscillator.
S M -2 0 L P a c k a g e D r a w in g
0 .3 8 "
(9 .6 5 )
0 .0 8 "
(2 .0 3 )
0 .1 2 5 "
(3 .2 0 )
T r a n s m itte r P in O u t
G N D 1
0 .0 2 "
(0 .5 1 )
R F IO
1
2 0
1 9
2
3
4
5
6
7
8
9
1 0
1 1
N C
1 8
1 7
1 6
1 5
1 4
1 3
1 2
G N D 3
C N T R L 0
C N T R L 1
V C C 2
N C
N C
N C
N C
V C C 1
N C
0 .4 3 "
(1 0 .9 )
0 .0 4 "
(1 .0 2 )
N C
N C
N C
0 .0 7 5 "
(1 .9 0 )
0 .1 3 "
(3 .3 0 )
N C
T X M O D
N C
G N D 2
.1 7 2 5
.1 9 7 5
.2 1 2 5
.4 6 0 0
.2 3 7 5
.3 8 2 5
.3 5 7 5
.3 1 7 5
.2 7 7 5
.2 3 7 5
.1 9 7 5
.1 5 7 5
.1 1 7 5
.1 0 2 5
.0 7 7 5
.1 4 0
0 .0 0 0
.2 7 0
.4 1 0
0 .0 0 0
D im e n s io n s in in c h e s
S M -2 0 L P C B P a d L a y o u t
4
Pin Descriptions
Pin
1
2
3
4
5
6
7
Name
GND1
VCC1
NC
NC
NC
NC
NC
Description
GND1 is the RF ground pin. GND2 and GND3 should be connected to GND1 by short, low-inductance traces.
VCC1 is the positive supply voltage pin for the transmitter output amplifier and the transmitter base-band circuitry.
VCC1 is usually connected to the positive supply through a ferrite RF decoupling bead which is bypassed by an
RF capacitor on the
supply side.
See the description of VCC2 (Pin 16) for additional information.
No connection. Printed circuit board pad may be grounded or floating.
No connection. Printed circuit board pad may be grounded or floating.
No connection. Printed circuit board pad may be grounded or floating.
No connection. Printed circuit board pad may be grounded or floating.
No connection. Printed circuit board pad may be grounded or floating.
The transmitter RF output voltage is proportional to the input current to this pin. A series resistor is used to adjust
the peak transmitter output voltage. 1.5 dBm of output power requires 250 µA of input current. In the ASK mode,
minimum output power occurs when the modulation driver sinks about 10 µA of current from this pin. In the OOK
mode, input signals less than 220 mV completely turn the transmitter oscillator off. Internally, this pin appears to
be a diode in series with a small resistor. Peak transmitter output power P
O
for a 3 Vdc supply voltage is approxi-
mately:
P
O
= 24*(I
TXM
)
2
, where P
O
is in mW, and the peak modulation current I
TXM
is in mA
A ±5% resistor value is recommended. In the OOK mode, this pin is usually driven with a logic-level data input
(unshaped data pulses). OOK modulation is practical for data pulses of 200 µs or longer. In the ASK mode, this
pin accepts analog modulation (shaped or unshaped data pulses). ASK modulation is practical for data pulses
8.7 µs or longer. This pin must be low in the power-down (sleep) mode. Please refer to the
ASH Transceiver De-
signer’s Guide
for additional information on modulation techniques.
9
10
11
12
13
14
15
16
NC
GND2
NC
NC
NC
NC
NC
VCC2
No connection. Printed circuit board pad may be grounded or floating.
GND2 is an IC ground pin. It should be connected to GND1 by a short, low inductance trace.
No connection. Printed circuit board pad may be grounded or floating.
No connection. Printed circuit board pad may be grounded or floating.
No connection. Printed circuit board pad may be grounded or floating.
No connection. Printed circuit board pad may be grounded or floating.
No connection. Printed circuit board pad may be grounded or floating.
VCC2 is the positive supply voltage pin for the transmitter oscillator. Pin 16 must be bypassed with an RF capaci-
tor, and must also be bypassed with a 1 to 10 µF tantalum or electrolytic capacitor. Power supply voltage ripple
should be limited to 10 mV peak-to-peak. See the
ASH Transceiver Designer’s Guide
for additional information.
CNTRL1 and CNTRL0 select the transmit modes. CNTRL1 high and CNTRL0 low place the unit in the ASK trans-
mit mode. CNTRL1 low and CNTRL0 high place the unit in the OOK transmit mode. CNTRL1 and CNTRL0 both
low place the unit in the power-down (sleep) mode. CNTRL1 is a high-impedance input (CMOS compatible). An
input voltage of 0 to 300 mV is interpreted as a logic low. An input voltage of Vcc - 300 mV or greater is inter-
preted as a logic high. An input voltage greater than Vcc + 200 mV should not be applied to this pin. A logic high
requires a maximum source current of 40 µA. A logic low requires a maximum sink current of 25 µA (1 µA in sleep
mode). This pin must be held at a logic level; it cannot be left unconnected.
CNTRL0 is used with CNTRL1 to control the operating modes of the transmitter. See the description of CNTRL1
for more information.
GND3 is an IC ground pin. It should be connected to GND1 by a short, low inductance trace.
RFIO is the transmitter RF output pin. This pin is connected directly to the SAW filter transducer. Antennas pre-
senting an impedance in the range of 35 to 72 ohms resistive can be satisfactorily matched to this pin with a se-
ries matching coil and a shunt matching/ESD protection coil. Other antenna impedances can be matched using
two or three components. For some impedances, two inductors and a capacitor will be required. A DC path from
RFIO to ground is required for ESD protection.
8
TXMOD
17
CNTRL1
18
19
CNTRL0
GND3
20
RFIO
5
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