MC68LC040RC25A Freescale Semiconductor, MC68LC040RC25A Datasheet - Page 344

• Manufacturer Part Number: MC68LC040RC25A
• Description: IC MPU 32BIT 25MHZ 179-PGA
• Manufacturer: Freescale Semiconductor

Specifications of MC68LC040RC25A

• Processor Type: M680x0 32-Bit
• Speed: 25MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 179-PGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -

Maximum power dissipation in the large buffer mode occurs for output:
Similar calculations for unterminated small buffers yield:
and
so
Assuming that the duty cycle of output j is driving a valid logic value instead of being
three-stated as given by DC j , then the following equation approximates total average
power dissipation in the output buffers:
I
summation is carried out by groups of pins instead of individual pins.
Motorola has calculated the values for DC
there will be 37.8 pins high, 41.5 pins low, and 11.7 pins three-stated. The following
examples demonstrate how to calculate the power dissipation that is added to small buffer
power dissipation numbers, assuming a termination as illustrated in Figure 11-18.
11-16
j
a. For the numbers listed in this section in a large buffer design with no caching.
b. For a single bus master system in a large buffer design with no caching or snooping
c. For the example b system with copyback caching, assuming 85% cache hit rate:
Low:
High:
and Z
P = (Number of Pins High) (P
and only standard features (i.e., TLN, UPA, BR, BB, LOCK, LOCKE, CIOUT, TIP, MI,
TDO, IPEND, PST not used):
P = (Number of Pins High) (P
P = (29.8 Pins
= 37.8 Pins
= 1.75 W
= 29.8 Pins
= 1.41 W
= 0.21 W
oj
P
P
are calculated for every pin as illustrated above. In practice the above
llb
hlb
= I
= I
2
2
R = (49.6 mA)
R = (50.8 mA)
30.1 mW per Pin + 41.5 Pins
30.1 mW per Pin + 34.5 Pins
30.1 mW per Pin + 34.5 Pins
Freescale Semiconductor, Inc.
For More Information On This Product,
P = I
I
Total
M68040 USER’S MANUAL
2
2
Go to: www.freescale.com
Outputs Used
x 6
x 12
P
P
hlb
hlb
I = 5 mA (by spec)
2
Number of
hsb
=
lsb
R = (5 mA)
) + (Number of Pins Low)
) + (Number of Pins Low)
j = 1
= 0.625 mW
= 0.625 mW
= 14.8 mW
= 30.1 mW
(I
j
j
for typical situations. On an average clock
DC
2
x 25
j
)
2
14.8 mW per Pin
14.8 mW per Pin
14.8 mW per Pin)
R
effj
(P
(P
llb
llb
)
)
(1 – 0.85)
MOTOROLA