TDA5251XT Infineon Technologies, TDA5251XT Datasheet - Page 49

• Manufacturer Part Number: TDA5251XT
• Manufacturer: Infineon Technologies

Specifications of TDA5251XT

• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Product Depth (mm): 4.4mm
• Product Length (mm): 9.7mm
• Operating Supply Voltage (min): 2.1V
• Operating Supply Voltage (max): 5.5V
• Lead Free Status / Rohs Status: Compliant

Figure 3-13
With the aid of this formula it becomes obvious that the higher the serial capacitance C V is, the
higher is the influence of L OSC .
The tolerance of the internal oscillator inductivity is much higher, so the inductivity is the dominating
value for the tolerance.
FSK modulation and tuning are achieved by a variation of C
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.
Data Sheet
C
L
=
C L ±
C
1
V
−
Crystal Oscillator
ω
1
=
2
L
C L
----------------------------------------------------------------------------------------- -
OSC
C
ω:
L
C
C
C
f:
N:
∆f:
OSC
1
L
L
0
1
+ −
:
:
:
:
±
↔
C 0
----------
N f ⋅
:
∆f
C
⋅
----------
N f ⋅
V
∆f
-R
⋅
=



crystal load capacitance for nominal frequency
angular frequency
inductivity of the crystal oscillator - typ: 2.2µH with pad of board
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
1
C
⋅
1
+



L
1
2
---------------------------------
+
+
⋅
ω
1
(
2
---------------------------------
C 0
2
TDA 5250
⋅
C
L
(
1
L
OSC
C
+
OSC
C
0
C L
1
+
C
)



L
)
49



f, C
v
.
L
C
V
2.1µH without pad
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TDA5251 F1
Version 1.1
Application
2007-02-26
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