TDA5252G2 INFINEON [Infineon Technologies AG], TDA5252G2 Datasheet - Page 49

• Manufacturer Part Number: TDA5252G2
• Description: ASK/FSK 915MHz Wireless Transceiver
• Manufacturer: INFINEON [Infineon Technologies AG]

In case of small frequency deviations (up to +/- 1000 ppm), the desired load capacitances for FSK
modulation are frequency depending and can be calculated with the formula below.
With C
Alternatively, an external AC coupled (10nF in series to 1k
The drive level should be approximately 100mVpp.
3.2.1
Generating ASK and FSK modulation 3 setable frequencies are necessary.
3.2.1.1
The resulting possible crystal oscillator frequencies are shown in the following Figure 3-13
Figure 3-13
In ASK receive mode the crystal oscillator is set to frequency f
offset to receive the ASK signal at f
Data Sheet
L+
and C
C L ±
Synthesizer Frequency setting
Possible crystal oscillator frequencies
L-
possible crystal oscillator frequencies
=
the necessary C
C
----------------------------------------------------------------------------------------- -
C
C
C
f:
N:
∆ f:
L
1
L
0
1
+ −
:
:
:
±
C
----------
N f ⋅
0
∆f
RX:
TX:
⋅
----------
N f ⋅
∆f
⋅



crystal load capacitance for nominal frequency
shunt capacitance of the crystal
motional capacitance of the crystal
crystal oscillator frequency
division ratio of the PLL
peak frequency deviation
FSK-
1
⋅
+
f



1
1
2
---------------------------------
v+
Deviation
+
0
⋅
*N (N: division ratio of the PLL).
(
for FSK HIGH and C
2
---------------------------------
C
⋅
C 1
0
(
Frequency
C
+
Nominal
C
FSK
ASK
0
C
1
f
+
L
0
C
)
Deviation



L
)
49



ASK
FSK+
f
2
Ω
v-
) signal can be applied at pin 19 (Xout).
for FSK LOW can be calculated.
2
to realize the necessary frequency
[3 – 18]
TDA5252 G2
Version 1.1
Application
2007-02-26
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