ATA5745-PXQW19 Atmel, ATA5745-PXQW19 Datasheet - Page 13

• Manufacturer Part Number: ATA5745-PXQW19
• Description: RF Receiver Switchable Rx-IC For RKE/TPMS 433MHz
• Manufacturer: Atmel
• Type: Receiverr

Specifications of ATA5745-PXQW19

• Package / Case: QFN-24
• Operating Frequency: 440 KHz
• Operating Supply Voltage: 2.7 V to 3.3 V
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 55 C
• Mounting Style: SMD/SMT
• Noise Figure: 7 dB
• Supply Current: 6.5 mA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

2.7
2.8
4596B–RKE–06/07
In-band Disturbers, Data Filter, Quasi-peak Detector, Data Slicer
RSSI Output
The ATA5745/ATA5746 can also receive FSK and ASK modulated signals if they are much
higher than the I1dBCP. It can typically receive useful signals at
to as the nonlinear dynamic range (that is, the maximum to minimum receiving signal), and is
95 dB for 10 Kbits/s Manchester (FSK). This value is useful if the transmitter and receiver are
very close to each other.
If a disturbing signal falls into the received band, or if a blocker is not a continuous wave, the
performance of a receiver strongly depends on the circuits after the IF filter. Hence, the demod-
ulator, data filter, and data slicer are important.
The data filter of the ATA5745/ATA5746 functions also as a quasi-peak detector. This results in a
good suppression of above mentioned disturbers and exhibits a good carrier-to-noise perfor-
mance. The required useful-signal-to-disturbing-signal ratio, at a BER of 10
in ASK mode and less than 3 dB (BR_Range_0 to BR_Range_2) and 6 dB (BR_Range_3) in
FSK mode. Due to the many different possible waveforms, these numbers are measured for the
signal, as well as for disturbers, with peak amplitude values. Note that these values are
worst-case values and are valid for any type of modulation and modulating frequency of the dis-
turbing signal, as well as for the receiving signal. For many combinations, lower
carrier-to-disturbing-signal ratios are needed.
The output voltage of the pin RSSI is an analog voltage, proportional to the input power level.
Using the RSSI output signal, the signal strength of different transmitters can be distinguished.
The usable dynamic range of the RSSI amplifier is 65 dB, the input power range P(RF
–110 dBm to –45 dBm, and the gain is 15 mV/dB.
typical device at 315 MHz with VS3V_AVCC = VS5V = 2.7V to 3.3V and T
+105°C with a matched input as shown in
1 dB more signal level is needed for the same RSSI results.
Figure 2-9.
Typical RSSI Characteristic at 315 MHz Versus Temperature and Supply Voltage
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
-130
-120
-110
-100
ATA5745/ATA5746 [Preliminary]
-90
-80
Pin (dBm)
Table 2-2
-70
-60
Figure 2-9
-50
and
-40
Figure 2-1 on page
-30
shows the RSSI characteristic of a
-20
–
10 dBm. This is often referred
-10
max; +9dB
2.7V, -40˚C
3.0V, -40˚C
3.3V, -40˚C
2.7V, 27˚C
3.0V, 27˚C
3.3V, 27˚C
2.7V, 105˚C
3.0V, 105˚C
3.3V, 105˚C
min; -9dB
–3,
6. At 433.92 MHz,
is less than 14 dB
amb
= –40°C to
IN
) is
13