ATA5760 ATMEL Corporation, ATA5760 Datasheet - Page 5

• Manufacturer Part Number: ATA5760
• Description: Ata5760 Uhf Ask/fsk Receiver
• Manufacturer: ATMEL Corporation

4896C–RKE–04/06
The nominal frequency f
using the following formula (low side injection):
f
To determine f
frequency is f
is tuned by the crystal frequency f
f
f
f
The relation is designed to achieve the nominal IF frequency of
f
f
for the 915 MHz version an IF frequency of f
The RF input either from an antenna or from an RF generator must be transformed to the RF
input pin LNA_IN. The input impedance of that pin is provided in the electrical parameters. The
parasitic board inductances and capacitances influence the input matching. The RF receiver
ATA5760/ATA5761 exhibits its highest sensitivity if the LNA is power matched. This makes the
matching to an SAW filter as well as to 50 or an antenna easier.
Figure 14-1 on page 30
ure 14-2 on page 30
matching network shown in
given in the electrical characteristics.
LO
LO
IF
IF
IF
IF
.
= f
= f
= 950 kHz for the 868.3 MHz and B
= 989 kHz for the 868.3 MHz and B
= f
LO
LO
RF
/915 for B
/878 for B
- f
IF
IF
LO
= 950 kHz. To achieve a good accuracy of the filter corner frequencies, the filter
, the construction of the IF filter must be considered at this point. The nominal IF
IF
IF
= 600 kHz
= 300 kHz
illustrates an according input matching for 868.3 MHz to an SAW. The input
shows a typical input matching network for f
LO
is determined by the RF input frequency f
Figure 14-1 on page 30
XTO
. This means that there is a fixed relation between f
IF
IF
= 600 kHz version,
= 300 kHz version and
IF
= 1.0 MHz results.
is the reference network for the parameters
ATA5760/ATA5761
RF
RF
= 868.3 MHz to 50 .
and the IF frequency f
IF
Fig-
and
IF
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