MOTOROLA
M68040 USER’S MANUAL
11-3
11.5 CLOCK AC TIMING SPECIFICATIONS (see Figure 11-1)
25 MHz
33 MHz
40 MHz
Num
Characteristic
Min
Max
Min
Max
Min
Max
Unit
Frequency of Operation
20
25
20
33
20
40
MHz
1
PCLK Cycle Time
20
25
15
25
12.5
25
ns
2
PCLK Rise Time
—
1.7
—
1.7
—
1.5
ns
3
PCLK Fall Time
—
1.6
—
1.6
—
1.5
ns
4
PCLK Duty Cycle Measured at 1.5 V
47.50
52.50
46.67
53.33
46.00
54.00
%
4a*
PCLK Pulse Width High Measured at 1.5 V
9.50
10.50
7
8
5.75
6.75
ns
4b*
PCLK Pulse Width Low Measured at 1.5 V
9.50
10.50
7
8
5.75
6.75
ns
5
BCLK Cycle Time
40
60
30
60
25
50
ns
6,7
BCLK Rise and Fall Time
—4—3—3ns
8
BCLK Duty Cycle Measured at 1.5 V
40
60
40
60
40
60
%
8a*
BCLK Pulse Width High Measured at 1.5 V
16
24
12
18
10
15
ns
8b*
BCLK Pulse Width Low Measured at 1.5 V
16
24
12
18
10
15
ns
9
PCLK, BCLK Frequency Stability
—
1000
—
1000
—
1000
ppm
10
PCLK to BCLK Skew
—
9
—
n/a
—
n/a
ns
*Specification value at maximum frequency of operation.
2
3
1
5
6
7
10
PCLK
BCLK
8B
8A
4A
4B
VM
V
IH
IL
VIH
VIL
VM
Figure 11-1. Clock Input Timing Diagram
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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