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The
Impedance Calibrator
performs calibration
between the internal
impedance of the
output terminal
and the external
cable impedance.
ATLab¡¯s
impedance calibrator
consists of TX driver,
reference voltage
generator, level
comparator, and
impedance controller.
TX
driver transmits
data to the output
terminals by driving
the low impedance
load.
Reference
voltage generator
produces reference
voltage that is
used to compare
the internal load
impedance with the
external cable impedance.
Level
comparator compares
reference voltage
and output signals
TXP and TXN, and
sends up or down
signal to the impedance
controller.
Finally,
the impedance controller
controls 7-bit signals
to fix the load
impedance.
RX
block utilizes the
calibration result
from the TX block.
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