TDA5255XT Infineon Technologies, TDA5255XT Datasheet - Page 39

• Manufacturer Part Number: TDA5255XT
• Manufacturer: Infineon Technologies

Specifications of TDA5255XT

• 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

Measured Magnitude of S11 of evalboard:
Figure 3-3
Above you can see the measured S11 of the evalboard. The –3dB-points are at 404MHz and
468MHz. So the 3dB-bandwidth is:
The loaded Q of the resonant circuit is:
The unloaded Q of the resonant circuit is equal to the Q of the inductor due to its losses.
An approximation of the losses of the input matching network can be made with the formula:
Data Sheet
L
OSS
=
B
−
Q
20
=
Q
U
*
f
L
U
log
=
=
Q
−
S11 measured




1
INDUCTOR
f
f
−
center
L
B
Q
Q
=
U
L
468




=
=
≈
−
MHz
434
20
32
64
*
2 ,
log
MHz
@
−
MHz
404



434
1
−
MHz
6
32
MHz
=
8 ,



6
8 ,
=
=
2
dB
64
MHz
39
[3 – 4]
[3 – 1]
[3 – 3]
[3 – 2]
TDA5255 E1
S11_measured_434.pcx.
Version 1.2
Application
2007-02-26