MPC8378CVRALFA datasheet(72/126 Pages) FREESCALE

72 / 126 page

MPC8378E PowerQUICC™ II Pro Processor Hardware Specifications, Rev. 2

Freescale Semiconductor

PCI Express

parasitic characteristics that cause the real PCI Express component to vary in impedance from the

compliance/test measurement load. The input receiver eye diagram is implementation specific and is not

specified. Rx component designer should provide additional margin to adequately compensate for the

degraded minimum receiver eye diagram (shown in Figure 47) expected at the input receiver based on an

adequate combination of system simulations and the return loss measured looking into the Rx package and

silicon. The Rx eye diagram must be aligned in time using the jitter median to locate the center of the eye

diagram.

The eye diagram must be valid for any 250 consecutive UIs.

A recovered Tx UI is calculated over 3500 consecutive unit intervals of sample data. The eye diagram is

created using all edges of the 250 consecutive UI in the center of the 3500 UI used for calculating the Tx

UI.

NOTE

The reference impedance for return loss measurements is 50. to ground for

both the D+ and D– line (that is, as measured by a Vector Network Analyzer

with 50. probes—see Figure 48). Note that the series capacitors, CPEACCTX,

are optional for the return loss measurement.

Figure 47. Minimum Receiver Eye Timing and Voltage Compliance Specification

VRX-DIFFp-p-MIN > 175 mV

0.4 UI = TRX-EYE-MIN

VRX-DIFF = 0 mV

(D+ D– Crossing Point)

VRX-DIFF = 0 mV

(D+ D– Crossing Point)

MPC8378CVRALFA 数据表(PDF) 72 Page - Freescale Semiconductor, Inc