NXP Semiconductors
UM191812
PN544 C2 User Manual
191812 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2010. All rights reserved.
User Manual Rev. 1.2 — 2010-06-16 94 of 172
Fig 57. Card Emulation RF step
9.6.6.2 Type B, 212kbps and 424kbps Passive Initiator and Active Initiator/Target
When TVDD is not configured to 2.7V, for VBAT higher than:
•
TVDD configured + 0.5V when TXLDO offset is used
• TVDD configured otherwise,
Some time after starting RF field, PN544 can have a lower step in RF amplitude for
around 2ms. This is due to a routine which optimizes modulation index around 10%
modulation depth. This routine is done with TVDD=2.7V.
Fig 58. RF Field Lower Step
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