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 38 of 120
NXP Semiconductors
MFRC631
High performance ISO/IEC 14443 A/B reader solution
However, the most important use of SIGIN/SIGOUT pins is the active antenna concept.
An external active antenna circuit can be connected to the digital circuit of the MFRC631.
SigOutSel has to be configured in that way that the signal of the internal Miller Coder is
sent to SIGOUT pin (SigOutSel = 4). SigInSel has to be configured to receive Manchester
signal with sub-carrier from SIGIN pin (SigInSel = 1).
It is possible, to connect a passive antenna to pins TX1, TX2 and RX (via the appropriate
filter and matching circuit) and at the same time an active antenna to the pins SIGOUT
and SIGIN. In this configuration, two RF-parts may be driven (one after another) by a
single host processor.