
LXT980/980A Dual-Speed, 5-Port Fast Ethernet Repeater
64
Datasheet
Figure 27. 100BASE-TX Transmit Timing - PHY MODE MII
Table 34. 100BASE-TX Transmit Timing Parameters - PHY Mode MII
Parameter
Sym
t
2A
t
2B
t
2C
t
2D
t
2E
Min
Typ
1
Max
Units
2
Test Condition
TXD, TX_EN, TX_ER Setup to TX_CLK High
10
–
–
ns
–
TXD, TX_EN, TX_ER Hold from TX_CLK High
5
–
–
ns
–
TX_EN sampled to CRS asserted
0
–
4
BT
–
TX_EN sampled to CRS de-asserted
0
–
16
BT
–
TX_EN sampled to TPOP/N active (Tx latency)
–
–
46
BT
–
1. Typical values are at 25
°
C and are for design aid only; not guaranteed and not subject to production testing.
2. Bit Time (BT) is the duration of one bit as transferred to/from the MAC and is the reciprocal of bit rate. BT for 100BASE-T =
10
s or 10 ns.
TX_CLK
TXD,
TX_EN,
TX_ER
CRS
TPOP/N
t
2A
t
2B
t
2C
t
2D
t
2E