Table 3. Package Thermal Characteristics
Characteristic
CBGA package thermal resistance, junction-to-case
thermal resistance (typical)
CBGA package thermal resistance, junction-to-lead
thermal resistance (typical)
Symbol
θ
JC
θ
JB
Value
0.03
3.8
Unit
°C/W
°C/W
Note:
Refer to Section 7.7, “Thermal Management Information“ for more information about thermal
management
The PPC740 and PPC750 incorporate a thermal management assist unit (TAU) com-
posed of a thermal sensor, digital-to-analog converter, comparator, control logic, and
dedicated special-purpose registers (SPRs). See the
PowerPC 740
TM
PowerPC 750
TM
RISC Microprocessor User’s Manual
for more information on the use of this feature.
Specifications for the thermal sensor portion of the TAU are found in Table 4.
Table 4. Thermal Sensor Specifications
Operating conditions are specified in Section Table 2., "Recommended Operating Conditions"
Num
1
2
3
Notes:
Characteristic
Temperature range
Comparator settling time
Resolution
0
Min
Max
128
—
—
Unit
°C
ms
°C
1
2
3
Notes
20
4
1.The temperature is the junction temperature of the die. The thermal assist unit's (TAU) raw output does
not indicate an absolute temperature, but it must be interpreted by software to derive the absolute
junction temperature. For information on how to use and calibrate the TAU, contact your local IBM
sales office. This specification reflects the temperature span supported by the design.
2. The comparator settling time value must be converted into the number of CPU clocks that need to be
written into the THRM3 SPR.
3. This value is guaranteed by design and is not tested.
.
Table 5. DC Electrical Specifications
Operating conditions are specified in Section Table 2., "Recommended Operating Conditions"
Characteristic
Input high voltage (all inputs except SYSCLK)
Input low voltage (all inputs except SYSCLK)
SYSCLK input high voltage
SYSCLK input low voltage
Symbol
VIH
VIL
CVIH
CVIL
Min
2.0
GND
2.4
GND
Max
3.465
0.8
OVdd
0.4
V
V
V
V
Unit
Notes
1,2
1
PPC740 and PPC750 Hardware Specifications
7 of 43
Preliminary and subject to change without notice
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