U2270B Datasheet, PDF (7/13 Pages) TEMIC Semiconductors – Read / Write Base Station IC

U2270B
Function Table
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Applications
To achieve the suitable application, consider the power
supply environment and the magnetic coupling situation.
The selection of the appropriate power supply operation
mode depends on the supply environment. If an
unregulated supply voltage in the range of V = 7 V to 16 V
is available, the internal power supply of the U2270B can
be used. In this case, the standby mode can be used and
an external low-current µC can be supplied.
The maximum transmission distance is also influenced by
the accuracy of the antenna’s resonance. Therefore, the
recommendations given above are proposals only. A good
compromise for the resonance accuracy of the antenna is
a value in the range of f_res = 125 kHz ± 3%. Further details
concerning the adequate application and the antenna
design is provided in the TEMIC application note
ANT019 and in the TEMIC article “Antenna Design
Hints”.
If a 5-V supply rail is available, it can be used to power _{The application of the U2270B includes the two}
the U2270B. In this case please check that the voltage is _{capacitors CIN and CHP whose values are linearly}
noise-free. An external power transistor is not necessary. _{dependend on the transponder’s data rate. The following}
The application depends also on the magnetic coupling
situation. The coupling factor mainly depends on the
transmission distance and the antenna coils. The
table gives the appropriate values for the most common
data rates. The values are valid for Manchester and
Bi-phase code.
following table lists the appropriate application for a
given coupling factor. The magnetic coupling factor can
Data Rate Input Capacitor Decoupling
be determined using the TEMIC test transponder coil.
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{Magnetic Coupling}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _Factor
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{k > 3%}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{k > 1%}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{k > 0.5%}
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ _{k > 0.3%}
Appropriate Application
Free-running oscillator
Diode feedback
Diode feedback
plus frequency altering
Diode feedback
plus fine frequency tuning
f = 125 kHz
f/32 = 3.9 kbit/s
f/64 = 1.95 kbit/s
(C_IN)
680 pF
1.2 nF
Capacitor (C_HP)
100 nF
220 nF
The following applications are typical examples. The
values of C_IN and C_HP correspond to the transponder’s
data rate only. The arrangement to fit the magnetic
coupling situation is also independent from other design
issues exept of one constellation. This constellation,
consisting of diode feedback plus fine frequency tuning
[ ^{together with the two-rail power supply should be used}
if the transmission distance is in the range of d 10 cm.
TELEFUNKEN Semiconductors
Rev. A3, 13-Dec-96
7 (13)