ATA2745M-TCQY Atmel, ATA2745M-TCQY Datasheet - Page 4

• Manufacturer Part Number: ATA2745M-TCQY
• Description: IC XMITTER ASK 433MHZ
• Manufacturer: Atmel

Specifications of ATA2745M-TCQY

• Frequency: 433MHz
• Applications: General Purpose
• Modulation Or Protocol: ASK
• Data Rate - Maximum: 20 kBaud
• Power - Output: 3dBm
• Current - Transmitting: 12.5mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Voltage - Supply: 6V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 16-SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Memory Size: -

3. General Description
4. Functional Description
4.1
4.2
5. Application Circuit
4
ASK Transmission
Take-over of the Clock Pulse in the Microcontroller
ATA2745
The fully integrated VCO and the single-ended open-collector output allow particularly simple,
low-cost RF miniature transmitters to be assembled. The single-ended output enables a consid-
erably simplified adaptation of both a magnetic loop antenna of any form or a
is because the load impedance must not be balanced as would be the case with a differential
output.
The XTO's frequency can be selected to be either 13.56 MHz or 9.844 MHz (USA). At these fre-
quencies, crystals have a very fast start-up time (< 1.5 ms), whereby a wait time of 5 ms to
10 ms is required until the transmitter IC is locked. This means that the processor does not need
to poll a lock detect output.
The ATA2745 is activated by EN = V
be modulated by means of pin ASK. V
message. The ASK input activates the power amplifier and the PLL.
The clock of the crystal oscillator can be used for clocking the microcontroller. The ATAR090
and ATAR890 have the special feature of starting with an integrated RC oscillator to switch on
the ATA2745 with V
message can be sent with crystal accuracy.
The following component values are recommendations for a typical application. C
are block capacitors. The values of these capacitors depend on the board layout. C
C
and f = 1 GHz should be as low as possible.
C
the appropriate impedance transformation is possible.
L
can be either printed on the PC board or be a discrete component.
Feed
5
Loop1
= 1 nF, and C
is an inductor for the antenna's DC current supply. A typical value is L
and C
Loop2
6
are selected so that the antenna oscillates in resonance and the matching to
= 22 nF are typically used here. For C
EN
= V
S
. 5 ms later, the 3.39-MHz clock frequency is present, so that the
S
. V
EN
ASK
remains equal to V
must remain 0V for 5 ms, then the output power can
5
, the impedance between f = 100 MHz
S
during the transmission of the
Feed
/ 4 antenna. This
= 220 nH. L
4898B–RKE–08/06
4
, C
5
4
, and C
= 1 nF,
Feed
6