CLRC63201T View Datasheet(PDF) - NXP Semiconductors.
Part Name
Description
MFG CO.
'CLRC63201T' PDF : 127 Pages View PDF
NXP Semiconductors
CLRC632
Standard multi-protocol reader solution
9.9.3.2 Calculating the relative source resistance
The reference source resistance RS(ref) can be calculated using Equation 6.
RSref
=
---------------------------------------1-----------------------------------------
MANTGsCfgCW
74---70--
EXPGsCfgCW
(6)
The reference source resistance (RS(ref)) during the modulation phase can be calculated
using ModConductance register’s GsCfgMod[5:0].
9.9.3.3 Calculating the effective source resistance
Wiring resistance (RS(wire)): Wiring and bonding add a constant offset to the driver
resistance that is relevant when pins TX1 and TX2 are switched to low-impedance. The
additional resistance for pin TX1 (RS(wire)TX1) can be set approximately as shown in
Equation 7.
RSwireTX1 500 m
(7)
Effective resistance (RSx): The source resistances of the driver transistors (RsMaxP
byte) read from the Product Information Field (see Section 9.2.1 on page 13) are
measured during the production test with CwConductance register’s
GsCfgCW[5:0] = 01h.
To calculate the driver resistance for a specific value set in GsCfgMod[5:0], use
Equation 8.
RSx = RSrefmaxP – RSwireTX1 RSrel + RSwireTX1
(8)
9.9.4 Pulse width
The envelope carries the data signal information that is transmitted to the card. It is an
encoded data signal based on the Miller code. In addition, each pause of the Miller
encoded signal is again encoded as a pulse of a fixed width. The width of the pulse is
adjusted using the ModWidth register. The pulse width (tw) is calculated using Equation 9
where the frequency constant (fclk) = 13.56 MHz.
tw
=
2 M------o---d----W-----i--d---t--h-----+-----1-
fc
(9)
9.10 Receiver circuitry
The CLRC632 uses an integrated quadrature demodulation circuit enabling it to detect an
ISO/IEC 14443 A or ISO/IEC 14443 B compliant subcarrier signal on pin RX.
• ISO/IEC 14443 A subcarrier signal: defined as a Manchester coded ASK modulated
signal
• ISO/IEC 14443 B subcarrier signal: defined as an NRZ-L coded BPSK modulated
ISO/IEC 14443 B subcarrier signal
CLRC632
Product data sheet
COMPANY PUBLIC
All information provided in this document is subject to legal disclaimers.
Rev. 3.7 — 27 February 2014
073937
© NXP Semiconductors N.V. 2014. All rights reserved.
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