RCT-433-AS / ASB
Embedding the wireless future..
Low-Cost SAW-stabilized surface mount
OOK RF transmitter
Typical Applications
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Remote Keyless Entry (RKE)
Remote Lighting Controls
On-Site Paging
Asset Tracking
Wireless Alarm and Security Systems
Long Range RFID
Automated Resource Management
Features
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315/418/433.92 MHz versions
Low Cost
1.5-12V operation
5mA current consumption at 3V
Small size.
0dBm output power at 3V
4800 baud operation
Description
The RCT-433-AS is ideal for remote control
applications where low cost and longer range are
required. The transmitter operates from a 1.5-12V
supply, making it ideal for battery-powered
applications. The transmitter employs a SAW-
stabilized oscillator, ensuring accurate frequency
control for best range performance. Output power
and harmonic emissions are easy to control,
making FCC and ETSI compliance easy. The
manufacturing-friendly SMT style package and low-
cost make the RCT-433-AS suitable for high
volume applications. The RCT-433-ASB is suitable
for IR reflow ovens and hot air soldering.
RCT-433-AS
RCT-433-ASB
Ordering Information
Frequency
433.92 MHz
433.92 MHz
Part Number
RCT-433-AS
RCT-433-ASB
Domestic and international orders:
Mouser Electronics 1-800-346-6873 (http://www.mouser.com)
Future Electronics (http://www.futureelectronics.com)
For a Radiotronix Representative in your area please visit
www.radiotronix.com
and visit our corporate
information page.
-i-
Document Control
Created By
Engineering Review
Marketing Review
Approved - Engineering
Approved - Marketing
Steve Montgomery
Tom Marks
Bryan Montgomery
Tom Marks
Bryan Montgomery
05/21/02
8/21/03
8/21/03
8/21/03
8/21/03
Revision History
Revision
1.1.0
1.2.0
1.3.0
1.4.0
Author
SJM
BFA
SJM
GWH
Date
05/21/02
07/30/03
8/21/03
6/7/05
Description
Document Created
Revision
Revision. Added troubleshooting and design tips.
Added RCT-433-ASB specification to datasheet.
- ii -
RCT-433-AS
Low-Cost SAW-stabilized surface mount OOK RF transmitter
© 2001,2002,2003 All Rights Reserved
Pin Out Diagram
Pin Description
Pin No.
Pin Name
Description
1
2
3
ANT
GND
DATA
4
VCC
50 ohm antenna output. The antenna port impedance affects output
power and harmonic emissions. An L-C low-pass filter may be
needed to sufficiently filter harmonic emissions.
Transmitter ground. Connect to ground plane.
Digital data input. This input is CMOS compatible and should be
driven with CMOS level inputs.
Pin 4 provides operating voltage for the transmitter. VCC should be
bypassed with a .01uF ceramic capacitor and filtered with a 4.7uF
tantalum capacitor. Noise on the power supply will degrade
transmitter noise performance.
Mechanical Drawing
0.30”
Figure 1: Mechanical Drawing of RCT-433-AS
Figure 2: Suggested Pad Layout
Figure 3: Mechanical Drawing of RCT-433-ASB
Figure 4: Suggested Pad Layout
-2-
6/7/2005
RCT-433-AS
Low-Cost SAW-stabilized surface mount OOK RF transmitter
© 2001,2002,2003 All Rights Reserved
RCT-433-ASB Reflow Details
The RCT-433-ASB is suitable for reflow ovens and heat guns. To prevent damage to the module
through excess heat, the reflow oven temperature profiling is very important. A suggested oven
profile is detailed in figure 5 below.
Figure 5: RCT-433-ASB Reflow Oven Temperature Profile
Absolute Maximum Ratings
Parameter
Power Supply and All Input
Pins
Storage Temperature
Soldering Temperature
(10sec)
1
Min
-0.3
-50
NA
Max
+15
100
350
Units
VDC
°C
°C
NOTES
1) The RCT-433-AS is hand solder only. The Transmitter is not suitable for IR reflow or hot air soldering.
The RCT-433-ASB is suitable for IR reflow and hot air soldering.
-3-
6/7/2005
RCT-433-AS
Low-Cost SAW-stabilized surface mount OOK RF transmitter
© 2001,2002,2003 All Rights Reserved
Detailed Electrical Specifications
Parameter (General)
Operating Voltage
Operating Current
DATA=VCC
Operating Current
DATA=GND
Frequency Accuracy
Center Frequency
Symbol
V
cc
I
cc
Icc
Min
1.5
---
---
-75
---
Typ.
3.0
4.5
100
0
315.0
418.0
433.92
Max
12
---
---
+75
---
Units
Volts DC
mA
uA
Khz
MHz
Notes
@3V
@3V
@3V
RCT-315-AS
RCT-418-AS
RCT-433-AS
TOL
fc
F
c
Output Power
Baud Rate – NRZ
---
DC
0
---
4800
dBm
BPS
@3V
Theory of Operation
OOK Modulation
OOK modulation is a binary form of amplitude modulation. When a logical 0 (data line low) is
being sent, the transmitter is off, fully suppressing the carrier. In this state, the transmitter current
is very low, less than 1mA.
When a logical 1 is being sent, the carrier is fully on. In this state, the module current
consumption is at its highest, about 4.5mA with a 3V power supply.
OOK is the modulation method of choice for remote control applications where power
consumption and cost are the primary factors. Because OOK transmitters draw no power when
they transmit a 0, they exhibit significantly better power consumption than FSK transmitters.
OOK data rate is limited by the start-up time of the oscillator. High-Q oscillators which have very
stable center frequencies take longer to start-up than low-Q oscillators. The start-up time of the
oscillator determines the maximum data rate that the transmitter can send.
DESIGN HINT “Using the RCT-433-AS with a microcontroller UART”:
Data should be
inverted when using the transmitter with a UART. The normal marking state of a UART is a logic
1, which will cause constant transmission. By inverting the data, the transmitter will be off in a
marking state and on in a spacing state (logical 0), ensuring that the transmitter is on only when
data is being sent. The output of the receiver would also need to be inverted to properly recover
data.
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6/7/2005
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