MPC8260A Motorola, MPC8260A Datasheet - Page 12

• Manufacturer Part Number: MPC8260A
• Description: Micro Processor
• Manufacturer: Motorola

Electrical and Thermal Characteristics
1.2.2
Table 6 describes thermal characteristics.
1.2.3
The average chip-junction temperature
where
For most applications P
is the following:
Solving equations (1) and (2) for K gives:
where K is a constant pertaining to the particular part. K can be determined from equation (3) by measuring
P
equations (1) and (2) iteratively for any value of T
1.2.3.1
Each V
should likewise be provided with a low-impedance path to ground. The power supply pins drive distinct
groups of logic on chip. The V
by-pass capacitors located as close as possible to the four sides of the package. The capacitor leads and
associated printed circuit traces connecting to chip V
per capacitor lead. A four-layer board is recommended, employing two inner layers as V
12
D
1
2
3
(at equilibrium) for a known T
Thermal resistance for TBGA
Assumes a single layer board with no thermal vias
Natural convection
Assumes a four layer board
CC
T
T
θ
P
P
P
P
K = P
A
JA
D
INT
I/O
D
J
pin should be provided with a low-impedance path to the board’s power supply. Each ground pin
= T
= ambient temperature °C
= P
= K/(T
= package thermal resistance
Thermal Characteristics
Power Considerations
= power dissipation on input and output pins (determined by user)
Characteristics
= I
Layout Practices
D
A
INT
DD
x (T
+ (P
J
+ P
x V
+ 273° C)
A
D
+ 273° C) +
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
I/O
x
DD
I/O
θ
JA
Watts (chip internal power)
< 0.3 x P
MPC826xA (HiP4) Family Hardware Specifications
)
CC
A
. Using this value of K
θ
power supply should be bypassed to ground using at least four 0.1 µF
INT
Table 6. Thermal Characteristics
JA
,
. If P
x P
T
,
J ,
junction to ambient
D
in °C can be obtained from the following:
Symbol
I/O
2
θ
θ
θ
θ
JA
JA
JA
JA
is neglected
A
.
CC
and ground should be kept to less than half an inch
,
the values of P
,
an approximate relationship between P
13.07
10.48
Value
9.55
7.78
,
°C/W
1
3
1
3
D
and T
°C/W
°C/W
°C/W
°C/W
Unit
J
can be obtained by solving
CC
and GND planes.
Air Flow
1 m/s
1 m/s
MOTOROLA
NC
NC
2
D
and T
(2)
(1)
(3)
J