XIO1100 Datasheet, PDF (19/36 Pages) Texas Instruments – X1 PCI Express
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Electrical Characteristics
PARAMETER
VTX–IDLE–DIFFp
Electrical idle differen-
tial peak output voltage
TERMINALS
TXP, TXN
MIN NOM
0
MAX
20
UNIT
mV
COMMENTS
VTX–IDLE–DIFFp = |VTXP–Idle − VTXN–Idle| ≤ 20 mV
See Note 5.
VTX–RCV–DETECT
The amount of voltage
change allowed during
receiver detection
TXP, TXN
600 mV The total amount of voltage change that a transmitter
can apply to sense whether a low impedance receiver is
present.
VTX–DC–CM
TXP, TXN
0
The TX dc common
mode voltage
3.6 V The allowed dc common mode voltage under any con-
dition.
ITX–SHORT
TX short circuit current
limit
TXP, TXN
90 mA Total current the transmitter can provide when shorted
to its ground
TTX–IDLE–MIN
TXP, TXN
50
Minimum time spent in
electrical idle
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
TXP, TXN
20 UI After sending an electrical idle ordered set, the transmit-
ter must meet all electrical idle specifications within this
time. This is considered a debounce time for the trans-
mitter 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
TXP, TXN
20 UI Maximum time to meet all TX specifications when tran-
sitioning 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
TXP, TXN
10
Differential return loss
dB Measured over 50 MHz to 1.25 GHz. See Note 7.
RLTX–CM
TXP, TXN
6
Common mode return
loss
dB Measured over 50 MHz to 1.25 GHz. See Note 7.
ZTX–DIFF–DC
DC differential TX
impedance
TXP, TXN
80
100
120 Ω TX dc differential mode low impedance
NOTES:
4. No test load is necessarily associated with this value.
5. Specified at the measurement point into a timing and voltage compliance test load and measured over any 250 consecutive TX
UIs.
6. A TTX–EYE = 0.75 UI provides for a total sum of deterministic and random jitter budget of TTX–JITTER–MAX = 0.25 UI for the
transmitter collected over any 250 consecutive TX UIs. The TTX–EYE–MEDIAN–to–MAX–JITTER specification ensures a jitter
distribution in which the median and the maximum deviation from the median is less than half of the total TX jitter budget collected
over any 250 consecutive TX UIs. It must be noted that the median is not the same as the mean. The jitter median describes the
point in time where the number of jitter points on either side is approximately equal, as opposed to the averaged time value.
7. The transmitter input impedance results in a differential return loss greater than or equal to 12 dB and a common mode return
loss greater than or equal to 6 dB over a frequency range of 50 MHz to 1.25 GHz. This input impedance requirement applies to
all valid input levels. The reference impedance for return loss measurements is 50 Ω to ground for both the P and N lines. Note
that the use of the series capacitors CTX is optional for the return loss measurement.
8. Measured between 20% and 80% at transmitter package terminals into a test load for both VTXP and VTXN
14 _SLLS690B
June 2006