tspc603r ATMEL Corporation, tspc603r Datasheet - Page 9

• Manufacturer Part Number: tspc603r
• Description: Powerpc 603e Risc Microprocessor Family Pid7t-603e
• Manufacturer: ATMEL Corporation

8.3.1
9. Power Consideration
9.1
5410B–HIREL–09/05
Dynamic Power Management
Thermal Management Example
The junction temperature can be calculated from the junction to ambient thermal resistance, as
follows:
Junction temperature:
so
Where:
Because dissipation is made through the PCB, R
siderably depending on the customer’s application.
In a typical customer application, if R
estimated.
Note that verification of external thermal resistance and case temperature should be performed
for each application. Thermal resistance depends on many factors including the amount of air
turbulence and can therefore vary considerably.
The PowerPC 603R is a microprocessor specifically designed for low-power operation. Like the
603e microprocessor version, the 603R provides both automatic and program-controllable
power reduction modes for progressive reduction of power consumption. This section describes
the hardware support provided by the 603R for power management.
Dynamic power management automatically powers up and down the individual execution units
of the 603R, based upon the contents of the instruction stream. For example, if no floating-point
instructions are being executed, the floating-point unit is automatically powered down. Power is
not actually removed from the execution unit; instead, each execution unit has an independent
clock input, which is automatically controlled on a clock-by-clock basis. Since CMOS circuits
consume negligible power when they are not switching, stopping the clock to an execution unit
effectively eliminates its power consumption. The operation of DPM is completely transparent to
software or any external hardware. Dynamic power management is enabled by setting bit 11 in
HID0 on power-up, following HRESET.
T
T
T
T
R
R
R
R
P is the power dissipated by the device
T
j
j
j
a
j
θja
θjc
cs
sa
=
= T
= T
= 110°C + (2.5 + 0.5 + 3) × 2.5 = 125°C
is the ambient temperature in the vicinity of the device
is the case to heat sink thermal resistance of the interface material
is the heat sink to ambient thermal resistance
is the junction to case thermal resistance of the device
T
is the junction to ambient resistance
C
a
a
+ R
+ (R
+ (R
θjc
cs
θjc
× P
+ R
+ R
sa
cs
) × P + R
+ R
sa
) × P
θjc
× P
cs
is 0.5°C/W, R
cs
and R
sa
is 3°C/W and Ta is 110°C, T
sa
are user values, and can vary con-
TSPC603R
j
can be
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