ATA5743P6-TGQY Atmel, ATA5743P6-TGQY Datasheet - Page 8

• Manufacturer Part Number: ATA5743P6-TGQY
• Description: IC RCVR ASK/FSK 600KHZ 20SOIC
• Manufacturer: Atmel

Specifications of ATA5743P6-TGQY

• Frequency: 300MHz ~ 450MHz
• Sensitivity: -110dBm
• Data Rate - Maximum: 10 kBaud
• Modulation Or Protocol: ASK, FSK
• Applications: RKE, Telemetering, Security Technology
• Current - Receiving: 7.5mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 105°C
• Package / Case: 20-SOIC (0.300", 7.50mm Width)
• Operating Frequency (max): 450000kHz
• Operating Temperature (min): -40C
• Operating Temperature (max): 105C
• Operating Temperature Classification: Industrial
• Operating Supply Voltage (min): 4.5V
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (max): 5.5V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Memory Size: -
• Lead Free Status / Rohs Status: Compliant

5. Analog Signal Processing
5.1
5.2
8
IF Amplifier
RSSI Amplifier
ATA5743
The signals coming from the RF front-end are filtered by the fully integrated 4
T h e I F c e n t e r f r e q u e n c y i s f
f
center frequency.
The ATA5743 is available with two different IF bandwidths. ATA5743P3, the version with
B
The receiver ATA5743P6 employs an IF bandwidth of B
together with the U2741B in ASK and FSK mode. If used in ASK applications, higher tolerances
for the receiver and PLL transmitter crystals are allowed. SAW transmitters exhibit much higher
transmit frequency tolerances compared to PLL transmitters. Generally, it is necessary to use
B
The subsequent RSSI amplifier enhances the output signal of the IF amplifier before it is fed into
the demodulator. The dynamic range of this amplifier is DR
operated within its linear range, the best SNR is maintained in ASK mode. If the dynamic range
is exceeded by the transmitter signal, the SNR is defined by the ratio of the maximum RSSI out-
put voltage and the RSSI output voltage due to a disturber. The dynamic range of the RSSI
amplifier is exceeded if the power of the input signal is 60 dB higher than the sensitivity of the
receiver.
In FSK mode the SNR is not affected by the dynamic range of the RSSI amplifier.
The output voltage of the RSSI amplifier is internally compared to a threshold voltage V
V
pin SENS and GND or V
this means it is possible to operate the receiver at a lower sensitivity.
If R
If R
is defined by the value of R
reduced sensitivity depends on the signal strength at the output of the RSSI amplifier.
Since different RF input networks may exhibit slightly different values for the LNA gain, the sen-
sitivity values given in the electrical characteristics refer to a specific input matching. This
matching is illustrated in
R
from full sensitivity to reduced sensitivity or vice versa at any time. In polling mode, the receiver
will not wake up if the RF input signal does not exceed the selected sensitivity. If the receiver
is already active, the data stream at pin DATA will disappear when the input signal is
lower than defined by the reduced sensitivity. Instead of the data stream, the pattern shown
in
Figure 6-26 on page
RF
IF
IF
Th_red
Sense
Figure 5-1 on page 9
= 433.92 MHz. For other RF input frequencies refer to
Sense
= 300 kHz, is well suited for ASK systems where Atmel’s PLL transmitter U2741B is used.
= 600 kHz together with SAW transmitters.
Sense
can be connected to V
is determined by the value of the external resistor R
is connected to GND, the receiver operates at full sensitivity.
is connected to V
29).
Figure 4-3 on page 7
S
is issued at pin DATA to indicate that the receiver is still active (see
. The output of the comparator is fed into the digital control logic. By
S
, the receiver operates at a lower sensitivity. The reduced sensitivity
Sense
S
or GND via a microcontroller. The receiver can be switched
, the maximum sensitivity by the SNR of the LNA input. The
I F
= 1 M H z f o r a p p l i c a t i o n s w h e r e f
and exhibits the best possible sensitivity.
IF
= 600 kHz. Both versions can be used
Table 4-1 on page 6
RSSI
Sense
= 60 dB. If the RSSI amplifier is
. R
Sense
is connected between
R F
to determine the
th
= 3 1 5 M H z o r
-order IF filter.
4839B–RKE–08/05
Th_red
.