MSC8103M1100 Motorola / Freescale Semiconductor, MSC8103M1100 Datasheet - Page 110

• Manufacturer Part Number: MSC8103M1100
• Description: Network Processor, Networking Digital Signal Processor
• Manufacturer: Motorola / Freescale Semiconductor

Electrical Design Considerations
4.2 Electrical Design Considerations
4.3 Power Considerations
4-2
The input voltage must not exceed the I/O supply
power-on reset. In turn,
no more than 100 ms.
V
Therefore the recommendation is to use “bootstrap” diodes between the power rails, as shown in Figure
4-1..
Select the bootstrap diodes such that a nominal V
until the
diodes are connected in series; each has a forward voltage (V
provide a 2.4 V drop, maintaining 0.9 V on the 1.6 V power line. Once the core/PLL power supply
stabilizes at 1.6 V, the bootstrap diodes will be reverse biased with negligible leakage current. The V
should be effective at the current levels required by the processor. Do not use diodes with a nominal V
that drops too low at high current.
The internal power dissipation consists of three components:
Power dissipation depends on the operating frequency of the different portions of the chip. Table 2-5
provides typical power values at the specified operating frequencies. To determine the typical power
dissipation for a given set of frequencies, use the following equations:
DD
— f
— f
— P
— All power numbers are in mW
— Power consumption is assumed to be linear with frequency. The first part of each equation
P
P
P
P
Where:
/
INT
CORE
CPM
SIU
V
CCSYN
in Table 2-5 in MHz
CPM frequency in MHz
computes a mw/MHz value that is then scaled based on the actual frequency used.
CORE
COREA
LCO
(f) = ((P
= P
V
(f) = ((P
(f) = ((P
DD
CORE
, P
/
must not exceed
is the core frequency, f
V
LSI
is the actual core frequency, F
CCSYN
SIU
CPM
I/O Power
+ P
Core/PLL
, and P
CORE
Supply
– P
Figure 4-1. Bootstrap Diodes for Power-Up Sequencing
SIU
V
power supply becomes active. In Figure 4-1., four MUR420 Schottky barrier
– P
LSI
DDH
V
– P
LCP
+ P
DDH
LCP
)/f
LCO
should not exceed
CPM
SIU
are the leakage power values specified in Table 2-5
)/f
can exceed
V
DDH
CPM
)/f
)
CORE
f
)
by more than 0.4 V at any time, including during power-on reset.
SIUA
SIU
f
)
CPMA
is the SIU frequency, and f
V
+ P
f
DD
COREA
LSI
SIUA
/
V
+ P
V
CCSYN
DD
DD
V
LCP
is the actual SIU frequency, and F
/
+ P
DDH
V
/V
CCSYN
LCO
by more than 3.3 V during power-on reset, but for
CCSYN
MUR420
MUR420
MUR420
MUR420
by more than 2.5 V at any time, including during
by more than 2.1 V during normal operation.
F
is sourced from the
) of 0.6 V at high currents, so these diodes
CPM
is the CPM frequency specified
3.3 V (V
1.6 V (V
V
DDH
CPMA
DDH
DD
power supply
/V
)
CCSYN
is the actual
)
F
F