Datasheet

Micrel, Inc.
KSZ8081MNX/KSZ8081RNB
August
19, 2015 53
Revision 1.4
Electrical Characteristics
(13)
(Continued)
Symbol Parameter Condition Min. Typ. Max. Units
All Pull-Up/Pull-Down Pins (including Strapping Pins)
pu Internal Pull-Up Resistance
V
DDIO
= 3.3V 30 45 73
kΩ V
DDIO
= 2.5V 39 61 102
V
DDIO
= 1.8V 48 99 178
pd Internal Pull-Down Resistance
V
DDIO
= 3.3V 26 43 79
kΩ V
DDIO
= 2.5V 34 59 113
V
DDIO
= 1.8V 53 99 200
100Base-TX Transmit (measured differentially after 1:1 transformer)
V
O
Peak Differential Output Voltage 100Ω termination across differential output 0.95 1.05 V
V
IMB
Output Voltage Imbalance 100Ω termination across differential output 2 %
t
r
, t
f
Rise/Fall Time 3 5 ns
Rise/Fall Time Imbalance 0 0.5 ns
Duty Cycle Distortion ±0.25 ns
Overshoot 5 %
Output Jitter Peak-to-peak 0.7 ns
10Base-T Transmit (measured differentially after 1:1 transformer)
V
P
Peak Differential Output Voltage 100Ω termination across differential output 2.2 2.8 V
Jitter Added Peak-to-peak 3.5 ns
t
r
, t
f
Rise/Fall Time 25 ns
10Base-T Receive
V
SQ
Squelch Threshold 5MHz square wave 400 mV
Transmitter – Drive Setting
V
SET
Reference Voltage of I
SET
R(I
SET
) = 6.49kΩ 0.65 V
REF_CLK Output
50MHz RMII Clock Output Jitter
Peak-to-peak. (Applies only to KSZ8081RNB
in RMII – 25MHz clock mode)
300 ps
100Mbps Mode – Industrial Applications Parameters
Clock Phase Delay – XI Input to
MII TXC Output
XI (25MHz clock input) to MII TXC (25MHz
clock output) delay, referenced to rising edges
of both clocks. (Applies only to KSZ8081MNX
in MII mode)
15 20 25 ns
t
llr
Link Loss Reaction (Indication)
Time
Link loss detected at receive differential inputs
to PHY signal indication time for each of the
following:
1. For LED mode 00, Speed LED output
changes from low (100Mbps) to high (10Mbps,
default state for link-down).
2. For LED mode 01, Link LED output changes
from low (link-up) to high (link-down).
3. INTRP pin asserts for link-down status
change.
4.4 µs