 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
ATA5745-PXPW Datasheet(PDF) 5 Page - ATMEL Corporation |
|
||||||||||||||||||||||||||||||
ATA5745-PXPW Datasheet(HTML) 5 Page - ATMEL Corporation |
|
|
5 / 44 page  5 4596B–RKE–06/07 ATA5745/ATA5746 [Preliminary] 2. RF Receiver As seen in Figure 1-3 on page 4, the RF receiver consists of a low-noise amplifier (LNA), a local oscillator, and the signal processing part with mixer, IF filter, IF amplifier with analog RSSI, FSK/ASK demodulator, data filter, and data slicer. In receive mode, the LNA pre-amplifies the received signal which is converted down to a 440-kHz intermediate frequency (IF), then filtered and amplified before it is fed into an FSK/ASK demodulator, data filter, and data slicer. The received signal strength indicator (RSSI) signal is available at the pin RSSI. 2.1 Low-IF Receiver The receive path consists of a fully integrated low-IF receiver. It fulfills the sensitivity, blocking, selectivity, supply voltage, and supply current specification needed to design an automotive inte- grated receiver for RKE and TPM systems. A benefit of the integrated receive filter is that no external components needed. At 315 MHz, the ATA5745 receiver (433.92 MHz for the ATA5746 receiver) has a typical system noise figure of 6.0 dB (7.0 dB), a system I1dBCP of –31 dBm (–30 dBm), and a system IIP3 of –24 dBm (–23 dBm). The signal path is linear for out-of-band disturbers up to the I1dBCP and hence there is no AGC or switching of the LNA needed, and a better blocking performance is achieved. This receiver uses an IF (intermediate frequency) of 440 kHz, the typical image rejec- tion is 30 dB and the typical 3-dB IF filter bandwidth is 420 kHz (f IF = 440 kHz ± 210 kHz, f lo_IF = 230 kHz and fhi_IF = 650 kHz). The demodulator needs a signal-to-noise ratio of 8.5 dB for 10 Kbits/s Manchester with ±38 kHz frequency deviation in FSK mode, thus, the resulting sensi- tivity at 315 MHz (433.92 MHz) is typically –105 dBm (–104 dBm). Due to the low phase noise and spurs of the synthesizer together with the 8th-order integrated IF filter, the receiver has a better selectivity and blocking performance than more complex double superhet receivers, without using external components and without numerous spurious receiv- ing frequencies. A low-IF architecture is also less sensitive to second-order intermodulation (IIP2) than direct conversion receivers where every pulse or amplitude modulated signal (especially the signals from TDMA systems like GSM) demodulates to the receiving signal band at second-order non-linearities. |
Similar Part No. - ATA5745-PXPW |
|
Similar Description - ATA5745-PXPW |
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.COM |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
