Transcript
AT-MT1-xxx Miniature AM Transmitter Module The AT-MT1 miniature UHF RF transmitter modules are well suited to applications where size constraints are dominant. Employing OOK modulation, the AT-MT1 transmits the carrier only when the data input signal is at a high level. Low current consumption and OOK modulation yield excellent power conservation characteristics making the AT-MT1 an ideal RF transmitter module for portable battery powered wireless applications. The AT-MT1 will suite one-to-one and multinode wireless links in applications including security, RKE, robotics, wireless data acquisition, remote control etc. and may be driven directly by microcontrollers and data encoders such as the DPC2400, HT12E, and the MC145026.
Mechanical Outline
Features
Miniature two pin package
SAW resonator stability
Data rates up to 2400bps
Optimal range 300ft
418MHz , 433.92MHz and 916.5MHz versions
CMOS / TTL compatible input
Low current (typ. 5mA)
Wide power supply range 1.5-13V
Compatible with our AM receiver modules
Schematic
ABACOM Technologies, Inc. • 383 Bering Ave • Etobicoke • ON • M8Z 3B1 • Tel +1(416)236-3858 • Fax +1(416)236-8866 www.abacom-tech.com
The AT-MT1 miniature UHF RF transmitter modules are well suited to applications where size constraints are dominant. Employing OOK modulation, the AT-MT1 transmits the carrier only when the data input signal is at a high level. Low current consumption and OOK modulation yield excellent power conservation characteristics making the AT-MT1 an ideal RF transmitter module for portable battery powered wireless applications.
Application Information Antenna Design The design and positioning of the antenna is as crucial as the module performance itself in achieving a good wireless system range. The following will assist the designer in maximizing system performance. The antenna should be kept as far away from sources of electrical interference as physically possible. If necessary, additional power line decoupling capacitors should be placed close to the module. The antenna 'hot end' should be kept clear of any objects, especially any metal as this can severely restrict the efficiency of the antenna to transmit power. Any ground planes restricting the radiation path to the antenna will also have the same effect.
When designing a PCB loop antenna, the inside area of the loop must be kept clear of any other components, as well as the area surrounding the loop. In other words the loop antenna must occupy an area of the PCB which is allocated to the antenna only. In some cases where PCB real estate is at a premium, the loop may designed as a discrete component which solders onto the board. The tuning capacitor is usually a variable capacitor which may be replaced with a fixed value capacitor once the tuned value has been determined. Provision can be made in the PCB layout to accommodate for this. For the 916.5MHz AT-MT1 transmitter modules, the variable capacitor value is typically very low, in the region of 0.5uF and the loop area will also be smaller than for the lower UHF devices. The value of the capacitor will be a function of the loop size and electrical dimensions as applies to any tuned circuit. Data Encoding
Best range is achieved with either a straight piece of wire, rod or PCB track. (. Further range may be achieved if the 1/4 wave antenna (15.5cm @ 433.92MHz) is placed perpendicular in the middle of a solid ground plane measuring at least 16cm radius. In this case, the antenna should be connected to the module via some 50 characteristic impedance coaxial cable such as RG174U or RG58U.
Data encoding and decoding is invariably required for successful RF data communications. Encoders which interface suitably with the ATMT1 RF transmitter modules such as Holtek’s HT12E, Motorola and National Semiconductor’s MC145026 and Microchip’s Keeloq devices, are typically used for data encoding in remote control
ABACOM Technologies, Inc. • 383 Bering Ave • Etobicoke • ON • M8Z 3B1 • Tel +1(416)236-3858 • Fax +1(416)236-8866 www.abacom-tech.com
and security applications. ABACOM’s DPC-2400 and DPC-64 encoder/ decoders are designed as a serial data interface between host processors such as microcontrollers or PC’s, and the ATMT1 RF transmitter module and companion receiver modules.
The DPC encoders/decoders perform the required data formating of serial data for RF wireless communications, greatly simplifying the design process
Example Application: Remote Control ATMT1 interfaced to HT12E data encoder (A) and companion receiver and data decoder (B) A
B C1
1nF
1nF
1
0.1uF
C2
4 5 6 7 8
A0 A1 A2 A3 A4 A5 A6 A7
VDD DOUT OSC1
16
220pF
1
DATA
2
GND 3
5
DATA
7
ANT
1M
R1
LEVEL
HT12E
VSS
AUDIO
ATMT1-XXX
680K
OSC2
9
RD
17
VDD
3
GND
2
18
6
18
VDD
17
DIN
16
OSC1
15
OSC2
14
VT
13
D3 D2 D1 D0
A0 A1 A2 A3 A4 A5 A6 A7
1
VSS
9
10k 47K
15
2
1
TE
14
AD11 AD10 AD9 AD8
13
ATR2-XXX
2 3 4 5 6 7 8
12 11
Data Output
10
12 11 10
HT12D
Example Application: Serial Data ATMT1 interfaced to the DPC 2400 serial data encoder (C) and companion receiver and DPC 2400 data decoder (D)
C
5V
5V
0.1uF
GND
8
2
Din
TXen
7
3
Busy
TXD
6
AUDIO
5
DATA
7
RD
Test
DPC2400 Encoder
5
2 220pF
DATA
3
ANT
GND ATMT1-XXX
GND
Mode
1
LEVEL
2
Host Processor
VDD
Vcc
4
D
5V
LED
0.1uF
1
0.1uF 1
5V
5V
Vcc
GND
8
1
RXDin Dready
7
2
Dout
6
3
N/C Mode
SendD
5
4
6
470R
ATR2-XXX DPC2400D
Receiving Host
ABACOM Technologies, Inc. • 383 Bering Ave • Etobicoke • ON • M8Z 3B1 • Tel +1(416)236-3858 • Fax +1(416)236-8866 www.abacom-tech.com
Absolute Maximum Ratings Operating Temperature: Storage Temperature:
-20C to +55C -40C to +85C
Supply Voltage (pin 1): Data input (pin 1):
15V 15V
Electrical Characteristics Parameter
Min.
Typ.
Max.
Units
1.5
5.0
13
Supply current @ Rd=1.0K
6
8.2
9
mA
RF power into 50 @ Rd=1.0K
2
4
6
dBm
DC Levels Supply Voltage
Current & RF Power For supply 7 to 13volts:
For supply 1.5 to 3.7 volts: Supply current @ Rd=51(data high)
4
7
mA
RF power into 50 @ Rd=51
-4
0
dBm
Data rate @ rf<500MHz
100
2400
bps
Data rate @ rf>500MHz
100
4800
bps
RF & Data
Applications Support:
[email protected] Disclaimer: Technical specifications are subject to change without notice. Whilst every effort has been made to ensure the accuracy of the information contained in this document, ABACOM Technologies Inc. does not assume responsibility for any errors or omissions that may exist. ABACOM Technologies Inc. does not assume responsibility for any damage caused through use or misuse of their products and the onus lies entirely with the end user in determining the suitability of and use of the product for any particular application. ABACOM Technologies Inc. products are not recommended for applications where human life may be at risk.
ABACOM Technologies, Inc. • 383 Bering Ave • Etobicoke • ON • M8Z 3B1 • Tel +1(416)236-3858 • Fax +1(416)236-8866 www.abacom-tech.com
