mpc8544e Freescale Semiconductor, Inc, mpc8544e Datasheet - Page 105

• Manufacturer Part Number: mpc8544e
• Description: Mpc8544e Powerquicc Iii Integrated Processor
• Manufacturer: Freescale Semiconductor, Inc

where:
The ratio of I
Solving for T, the equation becomes:
21 System Design Information
This section provides electrical and thermal design recommendations for successful application of the
MPC8544E.
21.1
This device includes six PLLs:
Freescale Semiconductor
•
•
•
•
•
I
I
V
V
V
V
I
I
q = Charge of electron (1.6 × 10
n = Ideality factor (normally 1.0)
K = Boltzman’s constant (1.38 × 10
T = Temperature (Kelvins)
The platform PLL generates the platform clock from the externally supplied SYSCLK input. The
frequency ratio between the platform and SYSCLK is selected using the platform PLL ratio
configuration bits as described in
The e500 core PLL generates the core clock as a slave to the platform clock. The frequency ratio
between the e500 core clock and the platform clock is selected using the e500 PLL ratio
configuration bits as described in
The PCI PLL generates the clocking for the PCI bus.
The local bus PLL generates the clock for the local bus.
There are two PLLs for the SerDes block.
fw
s
H
L
d
f
H
L
System Clocking
= Smaller diode bias current
= Saturation current
= Larger diode bias current
= Voltage forward biased
= Voltage at diode
= Forward current
= Diode voltage while I
= Diode voltage while I
H
V
to I
nT =
H
MPC8544E PowerQUICC III Integrated Processor Hardware Specifications, Rev. 4
– V
L
is usually selected to be 10:1. The above simplifies to the following:
1.986 × 10
L
V
= 1.986 × 10
H
– V
L
–4
Preliminary—Subject to Change Without Notice
L
H
is flowing
–4
is flowing
Freescale Confidential Proprietary
× nT
–19
Section 19.2, “CCB/SYSCLK PLL Ratio.”
Section 19.3, “e500 Core PLL Ratio.”
–23
C)
Joules/K)
System Design Information
105