CLRC663 Datasheet, PDF (51/132 Pages) NXP Semiconductors – Contactless reader IC

NXP Semiconductors
CLRC663
Contactless reader IC
f_out = 13.56 MHz  PLLDiv_FB /PLLDiv_Out
Table 41. Divider values for selected frequencies using the integerN PLL
Frequency [MHz]
PLLDiv_FB
PLLDiv_Out
accuracy [%]
4 6 8 10 12 20 24 1.8432 3.6864
23 27 23 28 23 28 23 28
28
78 61 39 38 26 19 16 206 103
0.04 0.03 0.04 0.08 0.04 0.08 0.04 0.01 0.01
8.8.3 Low-Power Oscillator (LPO)
The Low-Power Oscillator (LPO) is implemented to drive a wake-up counter (WUC). This
wakes up the system in regular time intervals and eases the design of a reader that is
regularly polling for card presence or implements a low-power card detection.
The LPO is trimmed during production. Unless a high accuracy of the LPO is required by
the application and the device is operated in an environment with changing ambient
temperatures, trimming of the LPO is not required. For a typical application making use of
the LPO for wake up from power down, the trim values set during production can be used.
Optional trimming is supported by a digital state machine which compares LPO-clock to
a reference clock. As reference the 13.56 MHz crystal clock is available.
Table 42. Setting of lpo_trimm [7:0]
value (decimal)
LPO clocks
4
16
5
32
6
64
7
128
CLRC663
Product data sheet
COMPANY PUBLIC
All information provided in this document is subject to legal disclaimers.
Rev. 3.3 — 3 April 2012
171133
© NXP B.V. 2012. All rights reserved.
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