Datasheet

MPC8308 PowerQUICC II Pro Processor Hardware Specification, Rev. 3
Freescale Semiconductor 39
PCI Express
AC peak common mode
input voltage
V
RX-CM-ACp
V
PEACPCMRX
= |V
RXD+
+ V
RXD-
|/2 -
V
RX-CM-DC
V
RX-CM-DC
= DC
(avg)
of |V
RX-D+
+
V
RX-D-
|/2
——150mV2
Differential return loss RL
RX-DIFF
Measured over 50 MHz to 1.25 GHz
with the D+ and D- lines biased at +300
mV and -300 mV, respectively.
15 — — dB 4
Common mode return loss RL
RX-CM
Measured over 50 MHz to 1.25 GHz
with the D+ and D- lines biased at 0 V.
6——dB4
DC differential input
impedance
Z
RX-DIFF-DC
RX DC differential mode impedance. 80 100 120  5
DC Input Impedance Z
RX-DC
Required RX D+ as well as D- DC
Impedance (50 ± 20% tolerance).
40 50 60  2, 5
Powered down DC input
impedance
Z
RX-HIGH-IMP-DC
Required RX D+ as well as D- DC
Impedance when the Receiver
terminations do not have power.
200 k — — 
6
Electrical idle detect
threshold
V
RX-IDLE-DET-DIFFp-p
V
PEEIDT
= 2*|V
RX-D+
-V
RX-D-
|
Measured at the package pins of the
Receiver
65 — 175 mV
—
Unexpected Electrical Idle
Enter Detect Threshold
Integration Time
T
RX-IDLE-DET-DIFF-
ENTERTIME
An unexpected Electrical Idle
(Vrx-diffp-p < Vrx-idle-det-diffp-p)
must
be recognized no longer than
Trx-idle-det-diff-entertime to signal an
unexpected idle condition.
——10ms
—
Total Skew L
RX-SKEW
Skew across all lanes on a Link. This
includes variation in the length of SKP
ordered set (for example, COM and one
to five SKP Symbols) at the RX as well
as any delay differences arising from
the interconnect itself.
— — 20 ns
—
Table 35. Differential Receiver (RX) Input Specifications (continued)
Parameter Symbol Comments Min Typical Max Units Note