Tnetx4090 thunderswitch ii, Switch – Texas Instruments THUNDERSWITCH II TNETX4090 User Manual
Page 65
TNETX4090
ThunderSWITCH II
9-PORT 100-/1000-MBIT/S ETHERNET
SWITCH
SPWS044E – DECEMBER 1997 – REVISED AUGUST 1999
65
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
PMA and GMII clock (see Figure 20)
NO.
MIN
MAX
UNIT
1
tr(Mxx_GCLK)
Pulse width low, Mxx_RFCLK
2.5
ns
2
th(Mxx_GCLK)
Pulse width high, Mxx_RFCLK
2.5
ns
3
tw(Mxx_GCLK)
Cycle time, Mxx_RFCLK
8
ns
PMA and GMII clock (see Figure 20)
NO.
MIN
MAX
UNIT
1
tr(Mxx_GCLK) Rise time, Mxx_RFCLK
1
ns
2
tf(Mxx_GCLK) Fall time, Mxx_RFCLK
1
ns
3
Accuracy
100
PPM
duty cycle
40%
60%
† tr and tf are measured between 20% and 80%, VDD(3.3-V) = min, output load (GTCLK) = 20pf.
Mxx_RFCLK
1
2
3
Figure 20. GMII Clock