
Micrel, Inc.
KSZ8851SNL/SNLI
August 2009
73
M9999-083109-2.0
Timing Specifications
SPI Input and Output Timing
Figure 15. SPI Interface Data Input Timing
Figure 16. SPI Interface Data Output Timing
Symbol
Parameter
Min
Typ
Max
Unit
fSCLK
SPI Clock Frequency
40
MHz
t1
CSN active setup time
8
ns
t2
SI data input setup time
3
ns
t3
SI data input hold time
3
ns
t4
CSN active hold time
8
ns
t5
CSN disable high time
8
ns
t6
(note)
SCLK falling edge to SO data output valid
7.5
9
ns
t7
CSN inactive to SO data output invalid
1
ns
Note: The last SI data falling edge of SCLK starts output data on SO from KSZ8851SNL
Table 16. SPI Data Input and Output Timing Parameters
SO
SCLK
SI
CSN
High Impedance
MSB bit
LSB bit
t1
t2
t3
1/fSCLK
t4
t5
SI
SCLK
SO
CSN
MSB bit
LSB bit
1/fSCLK
t5
LSB in
Don’t Care
t6
t7