
MPC8548E PowerQUICC III Integrated Processor Hardware Specifications, Rev. 5
70
Freescale Semiconductor
PCI Express
VTX-CM-DC-ACTIVE-
IDLE-DELTA
Absolute delta of
dc common
mode voltage
during L0 and
electrical idle
0—
100
mV
|VTX-CM-DC (during L0) + VTX-CM-Idle-DC (during
electrical idle)| <= 100 mV
VTX-CM-DC = DC(avg) of |VTX-D+ + VTX-D–|/2 [L0]
VTX-CM-Idle-DC = DC(avg) of |VTX-D+ +VTX-D–|/2
[electrical idle]
See Note 2.
VTX-CM-DC-LINE-DELTA Absolute delta of
DC common
mode between
D+ and D–
0—
25
mV
|VTX-CM-DC-D+ – VTX-CM-DC-D–| <= 25 mV
VTX-CM-DC-D+ = DC(avg) of |VTX-D+|
VTX-CM-DC-D–= DC(avg) of |VTX-D–|.
See Note 2.
VTX-IDLE-DIFFp
Electrical idle
differential peak
output voltage
0—
20
mV
VTX-IDLE-DIFFp = |VTX-IDLE-D+ – VTX-IDLE-D–|
<= 20 mV.
See Note 2.
VTX-RCV-DETECT
The amount of
voltage change
allowed during
receiver
detection
—
600
mV
The total amount of voltage change that a
transmitter can apply to sense whether a low
impedance receiver is present. See Note 6.
VTX-DC-CM
The TX DC
common mode
voltage
0
—
3.6
V
The allowed DC common mode voltage under any
conditions. See Note 6.
ITX-SHORT
TX short circuit
current limit
—
90
mA
The total current the transmitter can provide when
shorted to its ground
TTX-IDLE-MIN
Minimum time
spent in
electrical idle
50
—
UI
Minimum time a transmitter must be in electrical
idle utilized by the receiver to start looking for an
electrical idle exit after successfully receiving an
electrical idle ordered set
TTX-IDLE-SET-TO-IDLE
Maximum time
to transition to a
valid electrical
idle after
sending an
electrical idle
ordered set
—
20
UI
After sending an electrical idle ordered set, the
transmitter must meet all electrical idle
specifications within this time. This is considered
a debounce time for the transmitter to meet
electrical idle after transitioning from L0.
TTX-IDLE-TO-DIFF-DATA
Maximum time
to transition to
valid TX
specifications
after leaving an
electrical idle
condition
—
20
UI
Maximum time to meet all TX specifications when
transitioning from electrical idle to sending
differential data. This is considered a debounce
time for the TX to meet all TX specifications after
leaving electrical idle
RLTX-DIFF
Differential
return loss
12
—
dB
Measured over 50 MHz to 1.25 GHz.
See Note 4.
RLTX-CM
Common mode
return loss
6
—
dB
Measured over 50 MHz to 1.25 GHz.
See Note 4.
Table 52. Differential Transmitter (TX) Output Specifications (continued)
Symbol
Parameter
Min
Nom
Max
Unit
Comments