ATA5744N-TKSY Atmel, ATA5744N-TKSY Datasheet - Page 3

IC RCVR UHF ASK 433MHZ 20SSOP

ATA5744N-TKSY

Manufacturer Part Number
ATA5744N-TKSY
Description
IC RCVR UHF ASK 433MHZ 20SSOP
Manufacturer
Atmel
Datasheet

Specifications of ATA5744N-TKSY

Frequency
300MHz ~ 450MHz
Sensitivity
-112dBm
Data Rate - Maximum
10 kBaud
Modulation Or Protocol
ASK, FSK
Applications
RKE, Telemetering, Security Technology
Current - Receiving
7.1mA
Data Interface
PCB, Surface Mount
Antenna Connector
PCB, Surface Mount
Features
RSSI Equipped
Voltage - Supply
4.5 V ~ 5.5 V
Operating Temperature
-40°C ~ 105°C
Package / Case
20-SOIC (0.200", 5.30mm Width)
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Memory Size
-
Figure 2-2.
Block Diagram
CDEM
RSSI
AVCC
AGND
DGND
MIXVCC
LNAGND
LNA_IN
3. RF Front End
The RF front end of the receiver is a heterodyne configuration that converts the input signal into
a 1-MHz IF signal. According to
fier), LO (Local Oscillator), a mixer and RF amplifier.
The LO generates the carrier frequency for the mixer via a PLL synthesizer. The XTO (crystal
oscillator) generates the reference frequency f
erates the drive voltage frequency f
is divided by factor 64. The divided frequency is compared to f
tor. The current output of the phase frequency detector is connected to a passive loop filter and
thereby generates the control voltage VLF for the VCO. By means of that configuration, VLF is
controlled in a way that f
the following formula:
f
= f
XTO
LO
The XTO is a one-pin oscillator that operates at the series resonance of the quartz crystal.
According to
of that capacitor is recommended by the crystal supplier. The value of CL should be optimized
for the individual board layout to achieve the exact value of f
ing the system in terms of receiving bandwidth, the accuracy of the crystal and the XTO must be
considered.
4893A–RKE–11/05
BR_0
BR_1
ASK-
Dem_out
Demodulator
and data filter
RSSI
RSSI IF Amp
4. Order
LPF
3 MHz
IF Amp
VCO
LPF
3 MHz
f
LNA
64
Figure
2-2, the front end consists of an LNA (Low-Noise Ampli-
for the mixer. f
LO
/64 is equal to f
LO
XTO
/64
Figure
3-1, the crystal should be connected to GND via a capacitor CL. The value
ATA5744
DATA
Data interface
TEST
Test
MODE
DVCC
ENABLE
LFGND
Standby logic
LFVCC
XTO
XTO
LF
. The VCO (Voltage-Controlled Oscillator) gen-
XTO
is dependent on the voltage at pin LF. f
LO
by the phase frequency detec-
XTO
. If f
is determined, f
can be calculated using
LO
XTO
and hereby of f
. When design-
XTO
LO
LO
3

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