mcf51mm256 Freescale Semiconductor, Inc, mcf51mm256 Datasheet - Page 17

• Manufacturer Part Number: mcf51mm256
• Description: 32-bit Coldfire V1 Central Processor Unit
• Manufacturer: Freescale Semiconductor, Inc

The average chip-junction temperature (T
where:
For most applications, P
(if P
Freescale Semiconductor
I/O
T
θ
P
P
P
is neglected) is:
JA
A
D
int
I/O
1
2
3
4
# Symbol
1
2
3
4
= Ambient temperature, °C
= P
= Package thermal resistance, junction-to-ambient, °C/W
= I
Junction temperature is a function of die size, on-chip power dissipation, package thermal resistance, mounting site
(board) temperature, ambient temperature, air flow, power dissipation of other components on the board, and board
thermal resistance.
Junction to Ambient Natural Convection
1s — Single layer board, one signal layer
2s2p — Four layer board, 2 signal and 2 power layers
= Power dissipation on input and output pins — user determined
int
DD
T
θ
θ
+ P
T
JM
JA
JA
× V
A
I/O
DD
, Watts — chip internal power
Operating temperature range (packaged):
Maximum junction temperature
Thermal resistance
Thermal resistance
I/O
Single-layer board — 1s
Four-layer board — 2s2p
<< P
int
and can be neglected. An approximate relationship between P
Table 6. Thermal Characteristics
1,2,3,4
1, 2, 3, 4
P
T
D
J
J
= K ÷ (T
) in °C can be obtained from:
= T
Rating
A
+ (P
J
+ 273°C)
D
× θ
MCF51MM256
MCF51MM128
104-pin MBGA
100-pin LQFP
81-pin MBGA
80-pin LQFP
104-pin MBGA
100-pin LQFP
81-pin MBGA
80-pin LQFP
JA
)
Preliminary Electrical Characteristics
–40 to 105
–40 to 105
Value
150
67
39
67
53
53
39
41
39
°C/W
°C/W
Unit
°C
°C
D
and T
Eqn. 1
Eqn. 2
17
J