DC and Switching Characteristics
LatticeECP2/M Family Data Sheet
Lattice Semiconductor
PCI Express Electrical and Timing Characteristics
AC and DC Characteristics
Table 3-15.Transmit1, 2
Symbol
Description
Unit interval
Test Conditions
Min
Typ
Max
Units
UI
399.88
400
400.12
ps
Differential peak-to-peak output
voltage
V
V
V
V
V
0.8
0
1.0
-3.5
20
1.2
-7.96
—
V
TX-DIFF_P-P
De-emphasis differential output
voltage ratio
dB
mV
mV
V
TX-DE-RATIO
TX-CM-AC_P
RMS AC peak common-mode out-
put voltage
—
—
0
Maximum Common mode voltage
delta between n and p channels
—
25
TX-CM-DC-LINE-DELTA
TX-DC-CM
V
+
CCOB
5%
Tx DC common mode voltage
Output short circuit current
—
V
V
=0.0V
=0.0V
TX-D+
TX-D-
I
—
—
90
mA
TX-SHORT
Z
T
T
Differential output impedance
Tx output rise time
80
100
—
120
—
Ohms
UI
TX-DIFF-DC
20 to 80%
20 to 80%
0.125
0.125
TX-RISE
Tx output fall time
—
—
UI
TX-FALL
Lane-to-lane static output skew for
all lanes in port/link
L
—
—
1.3
ns
TX-SKEW
T
Transmitter eye width
0.75
—
—
—
—
—
UI
UI
nF
TX-EYE
3
T
0.125
200
TX-EYE-MEDIAN-TO-MAX-JITTER
C
AC coupling capacitor
75
TX
1. Values are measured at 2.5 Gbps.
2. Compliant to PCI Express v1.1.
3. Measured at 60ps with plug-in board and jitter due to socket removed.
Table 3-16. Receive
Symbol
Description
Unit Interval
Test Conditions Min.
Typ.
Max.
Units
UI
399.88
400
400.12
ps
Differential peak-to-peak input
voltage
V
0.175
—
—
V
RX-DIFF_P-P
V
Idle detect threshold voltage
DC differential input impedance
DC input impedance
65
80
—
100
50
—
175
120
60
mV
Ohms
Ohms
Ohms
UI
RX-IDLE-DET-DIFF_P-P
RX-DIFF-DC
Z
Z
Z
T
T
40
RX-DC
1
Power-down DC input impedance
Receiver eye width
200K
0.4
—
—
RX-HIGH-IMP-DC
—
—
RX-EYE
—
0.3
UI
RX-EYE-MEDIAN-TO-MAX-JITTER
Notes:
1. Measured with external AC-coupling on the receiver
2. Values are measured at 2.5 Gbps
3-42
LATTICE [ LATTICE SEMICONDUCTOR ]
