Datasheet

PN532_C1 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2017. All rights reserved.
Product data sheet
COMPANY PUBLIC
Rev. 3.6 — 28 November 2017
115436 117 of 222
NXP Semiconductors
PN532/C1
Near Field Communication (NFC) controller
8.6.9 Antenna presence self test
The goal of the Antenna Presence Self Test is to facilitate at assembly phase the
detection of the absence of the antenna and/or antenna matching components. Such a
detection is done by mean of measuring the current consumption.
Therefore the functionality is guaranteed within a restricted temperature and supply
voltage range:
• VBAT voltage is above 5 V
• Ambient temperature is between 0 and 40 C
8.6.9.1 Principle
The principle is explained with typical antenna tuning and matching components.
The testing operation can be managed via a dedicated register Table 158 on page 118
and requires the transmitter to be activated. When activated by asserting bit 0, the
detector will monitor the current consumption through the internal low dropout voltage
regulator. Any violation to the current limits will be reported via bits 7 and 6 of the register.
Fig 37. Disconnection localization for the antenna detection
Antenna
R
Q
R
1
C
Rx
R
2
L
0
C
1
R
Q
C
1
C
2
C
2
C
0
C
0
L
0
C
vmid
RX
VMID
TX1
TVSS1
TX2
PN532
TVSS2
1
2
3