MSC8103 Freescale Semiconductor / Motorola, MSC8103 Datasheet - Page 99

• Manufacturer Part Number: MSC8103
• Description: Network Digital Signal Processor
• Manufacturer: Freescale Semiconductor / Motorola

Design Considerations
This chapter includes design and layout guidelines for manufacturing boards using the MSC8103.
4.1 Thermal Design Considerations
The average chip-junction temperature
where
The user should set T
high, the user should either lower the ambient temperature or the power dissipation of the chip.
4.2 Electrical Design Considerations
The input voltage must not exceed the I/O supply
reset. In turn,
V
V
“bootstrap” diodes between the power rails, as shown in Figure 4-1.
Freescale Semiconductor
DDH
DDH
T
θ
P
P
P
A
D
INT
I/O
should not exceed
by more than 0.4 V at any time, including during power-on reset. Therefore the recommendation is to use
JA
= ambient temperature °C
= P
= package thermal resistance
= power dissipation on output pins in W—user determined
= I
INT
DD
V
+ P
DDH
× V
I/O
can exceed
DD
A
in W
in W—chip internal power
and P
V
DD
I/O Power
Core/PLL
Supply
/
Figure 4-1.
V
D
CCSYN
V
such that T
DD
MSC8103 Network Digital Signal Processor, Rev. 12
/
V
by more than 2.1 V during normal operation.
CCSYN
,
junction to ambient
,
T
T
J ,
J
J
Bootstrap Diodes for Power-Up Sequencing
by more than 3.3 V during power-on reset, but for no more than 100 ms.
in °C can be obtained from the following:
does not exceed the maximum operating conditions. In case T
= T
A
+ (P
V
DDH
D
• θ
by more than 2.5 V at any time, including during power-on
,
JA
°C/W
MUR420
MUR420
MUR420
MUR420
)
3.3 V (V
1.6 V (V
V
DD
/
V
DDH
CCSYN
DD
/V
)
CCSYN
must not exceed
)
Equation 1
J
is too
4
4-1