mpc8641 Freescale Semiconductor, Inc, mpc8641 Datasheet - Page 79

• Manufacturer Part Number: mpc8641
• Description: Integrated Host Processor Hardware Specifications
• Manufacturer: Freescale Semiconductor, Inc

To illustrate these definitions using real values, consider the case of a CML (Current Mode Logic)
transmitter that has a common mode voltage of 2.25 V and each of its outputs, TD and TD, has a swing
that goes between 2.5V and 2.0V. Using these values, the peak-to-peak voltage swing of the signals TD
and TD is 500 mV p-p. The differential output signal ranges between 500 mV and –500 mV. The peak
differential voltage is 500 mV. The peak-to-peak differential voltage is 1000 mV p-p.
15.4
With the use of high speed serial links, the interconnect media will cause degradation of the signal at the
receiver. Effects such as Inter-Symbol Interference (ISI) or data dependent jitter are produced. This loss
can be large enough to degrade the eye opening at the receiver beyond what is allowed in the specification.
To negate a portion of these effects, equalization can be used. The most common equalization techniques
that can be used are:
15.5
AC electrical specifications are given for transmitter and receiver. Long run and short run interfaces at
three baud rates (a total of six cases) are described.
The parameters for the AC electrical specifications are guided by the XAUI electrical interface specified
in Clause 47 of IEEE 802.3ae-2002.
XAUI has similar application goals to serial RapidIO, as described in Section 8.1. The goal of this standard
is that electrical designs for serial RapidIO can reuse electrical designs for XAUI, suitably modified for
applications at the baud intervals and reaches described herein.
15.6
LP-Serial transmitter electrical and timing specifications are stated in the text and tables of this section.
The differential return loss, S11, of the transmitter in each case shall be better than
The reference impedance for the differential return loss measurements is 100 Ohm resistive. Differential
return loss includes contributions from on-chip circuitry, chip packaging and any off-chip components
related to the driver. The output impedance requirement applies to all valid output levels.
It is recommended that the 20%–80% rise/fall time of the transmitter, as measured at the transmitter output,
in each case have a minimum value 60 ps.
It is recommended that the timing skew at the output of an LP-Serial transmitter between the two signals
that comprise a differential pair not exceed 25 ps at 1.25 GB, 20 ps at 2.50 GB and 15 ps at 3.125 GB.
Freescale Semiconductor
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A passive high pass filter network placed at the receiver. This is often referred to as passive
equalization.
The use of active circuits in the receiver. This is often referred to as adaptive equalization.
–10 dB for (Baud Frequency)/10 < Freq(f) < 625 MHz, and
–10 dB + 10log(f/625 MHz) dB for 625 MHz ≤ Freq(f) ≤ Baud Frequency
Explanatory Note on Transmitter and Receiver Specifications
Transmitter Specifications
Equalization
MPC8641 and MPC8641D Integrated Host Processor Hardware Specifications, Rev. 2
Serial RapidIO
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