Datasheet

MPC8308 PowerQUICC II Pro Processor Hardware Specification, Rev. 3
36 Freescale Semiconductor
PCI Express
Absolute delta of DC
common mode voltage
during L0 and electrical idle
V
TX-CM-DC- ACTIVE-
IDLE-DELTA
|V
TX-CM-DC (during L0)
- V
TX-CM-Idle-DC
(During Electrical Idle)
|<=100 mV
V
TX-CM-DC
= DC
(avg)
of |V
TX-D+
+
V
TX-D-
|/2 [L0]
V
TX-CM-Idle-DC
= DC
(avg)
of |V
TX-D+
+
V
TX-D-
|/2 [Electrical Idle]
0 — 100 mV 2
Absolute delta of DC
common mode between D+
and D–
V
TX-CM-DC-LINE-
DELTA
|V
TX-CM-DC-D+
- V
TX-CM-DC-D-
| <= 25 mV
V
TX-CM-DC-D+
= DC
(avg)
of |V
TX-D+
|
V
TX-CM-DC-D-
= DC
(avg)
of |V
TX-D-
|
0—25mV2
Electrical idle differential
peak output voltage
V
TX-IDLE-DIFFp
V
PEEIDPTX
= |V
TX-IDLE-D+
-V
TX-IDLE-D-
|
<= 20 mV
0—20mV2
Amount of voltage change
allowed during receiver
detection
V
TX-RCV-DETECT
The total amount of voltage change that
a transmitter can apply to sense whether
a low impedance Receiver is present.
—600—mV6
TX DC common mode
voltage
V
TX-DC-CM
The allowed DC Common Mode voltage
under any conditions.
—3.6—V6
TX short circuit current limit I
TX-SHORT
The total current the Transmitter can
provide when shorted to its ground
——90mA—
Minimum time spent in
electrical idle
T
TX-IDLE-MIN
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
50 — — UI —
Maximum time to transition
to a valid electrical idle after
sending an electrical idle
ordered set
T
TX-IDLE-SET-TO-ID
LE
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.
——20UI—
Maximum time to transition
to valid TX specifications
after leaving an electrical
idle condition
T
TX-IDLE-TO-DIFF-D
ATA
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
——20UI—
Differential return loss RL
TX-DIFF
Measured over 50 MHz to 1.25 GHz. 12 — — dB 4
Common mode return loss RL
TX-CM
Measured over 50 MHz to 1.25 GHz. 6 — — dB 4
DC differential TX
impedance
Z
TX-DIFF-DC
TX DC Differential mode Low
Impedance
80 100 120  —
Transmitter DC impedance Z
TX-DC
Required TX D+ as well as D- DC
Impedance during all states
40 — —  —
Lane-to-Lane output skew L
TX-SKEW
Static skew between any two Transmitter
Lanes within a single Link
— — 500 + 2
UI
ps —
Table 34. Differential Transmitter (TX) Output Specifications (continued)
Parameter Symbol Comments Min Typical Max Units Note