CF45538NSRG4 Datasheet, PDF (13/19 Pages) Texas Instruments – TIRIS RF-Module IC for Automotive

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Typical Transmitter Circuit Configuration
VCC
GND
TXCT
RXDT
RXCK
0.1uF
(*)
(*)
17.1776MHz
100uF
NC
16 15 14 13 12 11 10 9
TRMI4S55573788N0SNS
1234
56 7 8
2SJ182
120
2SK974
1S1588
120pF
120pF
1M
1M
10K
1200pF
100
ANTENNA
(L=48uH)
68pF
68pF
68pF
1S1588 0.01uF 0.01uF 0.01uF
* When configuring an applied circuit, take the following into account:
• Choose the capacity of a resonance capacitor for clock generator oscillator in accordance with the
oscillator characteristics.
• Define the frequency accuracy and variation of the clock generator oscillator by conversion based on
the specifications for the TIRIS transponder to be used together so that it can be within the range of
17.17248 MHz to 17.18272 MHz (standard frequency: 17.1776 MHz).
• Select the values at resonance points around 134.2 kHz for L and C of the antenna circuit,
respectively. (In the example illustrated above, the following combination is used: antenna: 48 µH;
capacitor: 0.03 µF = 0.01 µF × 3 units)
• It is desirable to use a MOSFET having a low on-state resistance for antenna driver
11 Typical Transmitter Circuit Configuration
This RF-module IC is provided with “TXHI” and “TXLO” terminals which can drive external MOSFETs for
driving the LC serial resonance antenna circuit. This resonance antenna circuit is to send 134.2-kHz
signals to the remote TIRIS transponder. Use these terminals as illustrated below.
SCBU036 – December 1996
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TIRIS RF-Module IC for Automotive
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