Datasheet

Micrel, Inc.
KSZ8081MNX/KSZ8081RNB
August
19, 2015 62
Revision 1.4
Power-up/Reset Timing
The KSZ8081MNX/RNB reset timing requirement is summarized in Figure 20 and Table 22.
Figure 20. Power-up/Reset Timing
Table 22. Power-up/Reset Timing Parameters
Parameter Description Min. Max. Units
t
VR
Supply voltage (V
DDIO,
V
DDA_3.3
) rise time 300 µs
t
SR
Stable supply voltage (V
DDIO,
V
DDA_3.3
) to reset high 10 ms
t
CS
Configuration setup time 5 ns
t
CH
Configuration hold time 5 ns
t
RC
Reset to strap-in pin output 6 ns
The supply voltage (V
DDIO
and V
DDA_3.3
) power-up waveform should be monotonic. The 300µs minimum rise time is from
10% to 90%.
For warm reset, the reset (RST#) pin should be asserted low for a minimum of 500µs. The strap-in pin values are read
and updated at the de-assertion of reset.
After the de-assertion of reset, wait a minimum of 100µs before starting programming on the MIIM (MDC/MDIO) interface.