htrc11001t/03ee NXP Semiconductors, htrc11001t/03ee Datasheet - Page 6

• Manufacturer Part Number: htrc11001t/03ee
• Description: Hitag Reader Chip
• Manufacturer: NXP Semiconductors

NXP Semiconductors
037031
Product data sheet
PUBLIC
9.6 Idle and power-down mode
The phase between the driver excitation signal and the antenna tap voltage depends on
the antenna tuning. With optimum tuning, the phase of the antenna tap voltage is 90
degrees off the antenna driver signal. Detuning of the antenna resonant circuit results in a
change of this phase relationship.
The HTRC110's built-in phase measurement unit allows the measurement of this phase
relationship with a resolution of 360°/64 = 5.625°. This can be used to compute a
sampling time that compensates the mistuning of the reader antenna. The phase
measurement procedure can be carried out:
Before the system is switched into WRITE_TAG-mode, the demodulator has to be frozen.
This is internally done by clamping the input of the amplifier/filter unit to QGND. Doing so
avoids large transients in the amplifier and the digitizer, which could affect settling times.
In addition to the clamping, there exist other means in the HTRC110, which allow further
reduction of the settling times. All the parts of the circuitry, which are associated with these
functions, are controlled by the FREEZE0, FREEZE1 and THRESET bits, which are
located in configuration page 2.
For more details concerning WRITE Timing, Demodulator Setting, Power Up Sequence,
etc. please refer to the HTRC110 application note
The HTRC110 can be switched into idle mode via setting the PD-bit and resetting the
PD_MODE-bit. In this idle mode, only the oscillator and a few other system components
are active.
It is also possible to switch the IC completely off. This is achieved by the power-down
mode (PD = 1, PD_MODE = 1). Within this mode also the clock oscillator is switched off.
This reduces the supply current of the HTRC110 to less than 20 μA.
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either once before the first communication starts, if the position of the transponder
does not change with the respect to the reader antenna
or during the communication (after sending the write pulses and before receiving the
answer of the transponder), if the tag is moving.
All information provided in this document is subject to legal disclaimers.
Rev. 3.1 — 9 February 2010
037031
(Ref.
1).
HTRC110
HITAG reader chip
© NXP B.V. 2010. All rights reserved.
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