tda5255e1 Infineon Technologies Corporation, tda5255e1 Datasheet - Page 54

• Manufacturer Part Number: tda5255e1
• Description: Ask/fsk 434mhz Wireless Transceiver
• Manufacturer: Infineon Technologies Corporation

Confidential
Figure 3-19
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.
Preliminary Specification
C
vm
C v+
=
Name
C 20
C 21
C 22
(
---------------------------------------------------------------------------------------------------------------------------------------- -
Typical values of parasitic capacitances
C
=
C
parasitics of the switching network
v1
v1
(
-------------------------------------------------------------------------------------------------------
C v1
C v1
+
+
C
C
tune1
C v-
+
tune1
+
C tune1
C
C
C tune1
V1
V2
=
)
+
×
C v1
(
C
C
)
v2
C
f, C
+
v2
×
V3
+
(
C v2
C v2
+
L
C tune1
+
C
C
XSWA 22
XSWF 20
XOUT 19
XGND 23
20
+
20
+
v
XIN 21
C 20
can be calculated:
C 20
+
+
C
+
C
FSK-: 2,8 pF / FSK+&ASK: 2.2pF
v3
C 21
+
v3
+
C
C
+
+
tune2
tune2
C
C
22
54
C
22
22
L
+
+
)
C
C
+
tune2
C
tune2
C
4,6 pF
21
Value
21
1 pF
-R
)
C
+
20
C
21
C
C
tune2
tune1
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TDA5255 E1
Version 1.1
QOSC_parasitics.wmf
Application
2002-11-28