Product data

MFRC631 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2014. All rights reserved.
Product data sheet
COMPANY PUBLIC
Rev. 3.3 — 4 February 2014
227433 37 of 120
NXP Semiconductors
MFRC631
High performance ISO/IEC 14443 A/B reader solution
During low power card detection the DC levels at the I- and Q-channel mixer outputs are
evaluated. This requires that mixers are directly connected to the ADC. This can be
configured by setting the bit Rx_ADCmode in register Rcv (38h).
8.6.4 Active antenna concept
Two main blocks are implemented in the MFRC631. A digital circuitry, comprising state
machines, coder and decoder logic and an analog circuitry with the modulator and
antenna drivers, receiver and amplification circuitry. For example, the interface between
these two blocks can be configured in the way, that the interfacing signals may be routed
to the pins SIGIN and SIGOUT. The most important use of this topology is the active
antenna concept where the digital and the analog blocks are separated. This opens the
possibility to connect e.g. an additional digital block of another MFRC631 device with a
single analog antenna front-end.
The Table 23 and Table 24 describe the necessary register configuration for the use case
active antenna concept.
The interface between these two blocks can be configured in the way, that the interfacing
signals may be routed to the pins SIGIN and SIGOUT (see Figure 27 “
Overview
SIGIN/SIGOUT Signal Routing”).
This topology supports, that some parts of the analog part of the MFRC631 may be
connected to the digital part of another device.
The switch SigOutSel in registerSigOut can be used to measure signals. This is especially
important during the design In phase or for test purposes to check the transmitted and
received data.
Fig 26. Block diagram of the active Antenna concept
Table 23. Register configuration of MFRC631 active antenna concept (DIGITAL)
Register Value (binary) Description
SigOut.SigOutSel 0100 TxEnvelope
Rcv.SigInSel 10
11
Receive over SigIn (ISO/IEC14443A)
Receive over SigIn (Generic Code)
DrvCon.TxSel 00 Low (idle)
Table 24. Register configuration of MFRC631 active antenna concept (Antenna)
Register Value (binary) Description
SigOut.SigOutSel 0110
0111
Generic Code (Manchester)
Manchester with Subcarrier (ISO/IEC14443A)
Rcv.SigInSel 01 Internal
DrvCon.TxSel 10 External (SigIn)
RxCtrl.RxMultiple 1 RxMultiple on
001aam307
SIGIN
SIGINSIGOUT
SIGOUT
READER IC
(DIGITAL)
READER IC
(ANTENNA)