TDA5252G2 INFINEON [Infineon Technologies AG], TDA5252G2 Datasheet - Page 53

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

Table 3-2
With the given parasitics the actual C
Note: Please keep in mind also to include the Pad parasitics of the circuit board.
3.2.4
1. Determination of necessary crystal frequency using formula [3-19].
2. Determine corresponding C
3. Necessary C
1. When the necessary C
Data Sheet
FSK-receive) are known the external capacitors and the internal tuning caps can be calculated
using the following formulas:
e.g.
C
e.g. f
e.g. C
vm
C
=
v+
FSK-
Name
Calculation of the external capacitors
L FSK
C 20
C 21
C 22
(
---------------------------------------------------------------------------------------------------------------------------------------- -
Typical values of parasitic capacitances
C
=
C v1
V
v1
C
(
-------------------------------------------------------------------------------------------------------
= f
V
using formula [3-17].
C
C v1
- = C
+
−
+
v1
COSC LOW
C
=
C tune1
tune1
C v-
+
+
C
L ±
C
C tune1
L
tune1
,
1
FSK
v
=
)
for the 3 frequencies (C
+
⋅
C v1
−
(
C v2
C
+
)
Load
+
v2
⋅
(
+
(
C v2
2
C
+
C tune1
+
π
v2
1
C 20
applying formula [3-18].
f
C
FSK
+
20
+
v
C 20
+
−
can be calculated:
C
+
)
20
C
+
2
C
FSK-: 2,8 pF / FSK+&ASK: 2.2pF
v3
*
+
C 21
v3
+
L
C
C
+
OSC
+
tune2
tune2
C 22
C
53
22
+
+
)
v-
C
+
C
tune2
for FSK LOW, C
tune2
C 21
4,6 pF
Value
1 pF
)
+
C
21
v+
for FSK HIGH and C
[3 – 24]
[3 – 26]
[3 – 25]
[3 – 25]
TDA5252 G2
Version 1.1
Application
2007-02-26
[3 – 29]
vm
for