
LXT980/980A Dual-Speed, 5-Port Fast Ethernet Repeater
60
Datasheet
Table 27. I/O Electrical Characteristics
Parameter
Sym
Min
Typ
1
Max
Units
Test Conditions
Input Low voltage
V
IL
–
–
0.8
V
TTL inputs
–
–
30
% V
CC
CMOS inputs
2
–
–
1.0
Schmitt triggers
3
Input High voltage
V
IH
2.0
–
–
V
TTL inputs
70
–
–
% V
CC
CMOS inputs
2
V
CC
- 1.0
–
–
V
Schmitt triggers
3
Hysteresis voltage
–
1.0
–
–
V
Schmitt triggers
3
Output Low voltage
V
OL
–
–
0.4
V
I
OL
= 1.6 mA
Output Low voltage (LED)
V
OLL
–
–
1.0
V
I
OLL
= 10 mA
Output High voltage
V
OH
2.4
–
–
V
I
OH
= 40
μ
A
Input Low current
I
IL
-100
–
–
μ
A
–
Input High current
I
IH
–
–
100
μ
A
–
Output rise / fall time
T
RF
–
3
10
ns
C
L
= 15 pF
1. Typical values are at 25
°
C and are for design aid only; not guaranteed and not subject to production testing.
2. Does not apply to IRB pins. Refer to
Table 28
and
Table 29
for IRB I/O characteristics.
3. Applies to RESET and CLK25 pins only.
Table 28. 100 Mbps IRB Electrical Characteristics
Parameter
Symbol
Min
Typ
1
Max
Units
Test Conditions
Output Low voltage
V
OL
–
.3
.7
V
R
L
= 330
Output rise or fall time
T
RF
–
4
10
ns
C
L
=
1
5 pF
Input High voltage
V
IH
V
CC
- 2.0
–
–
V
CMOS inputs
V
CC
- 1.0
–
–
V
IR100CLK (Schmitt trigger)
Input Low voltage
V
IL
–
–
2.0
V
CMOS inputs
–
–
1.0
IR100CLK (Schmitt trigger)
Hysteresis voltage
–
1.0
–
–
V
IR100CLK (Schmitt trigger)
IR100CFS
current
single drive
–
–
8.0
–
mA
R
L
= 240
collision
–
–
16.0
–
mA
R
L
= 240
R
L
= 91
2
R
L
= 91
2
IR100CFSBP
current
single drive
–
–
22.0
–
mA
collision
–
–
45.0
–
mA
IR100CFS/BP
voltage
single drive
–
–
2.8
–
V
–
collision
–
–
0.6
–
V
–
1. Typical values are at 25
°
C and are for design aid only; they are not guaranteed and not subject to production testing.
2. 91
resistors provide greater noise immunity. Systems using 91
resistors
are backwards stackable with systems using
100
resistors.