PowerPC 740 and PowerPC 750 Embedded Microprocessor
IBM CMOS 0.20 um Copper Technology EMPPC740L and EMPPC750L
1
Package Thermal Characteristics
Characteristic
Symbol
740
750
Unit
Thermal resistance, junction-to-case (top sur-
face of die) typical
θJC
0.03
0.03
°C/W
2
2
Thermal resistance, junction-to-balls, typical
θJB
°C/W
3.8 - 7.1
16.0
3.8 - 7.6
15.1
Thermal resistance, junction-to-ambient, at air-
flow, no heat sink, typical
50 FPM
100 FPM
150 FPM
200 FPM
°C/W
°C/W
°C/W
°C/W
15.4
16.4
14.9
14.2
14.4
13.7
2
Package Size
Die Size
Note:
21 x 21
25 x 25
mm
2
5.12 x 7.78
5.12 x 7.78
mm
1. Refer to Section “Thermal Management Information,” on page 39 for more information about thermal management.
2. 3.8 °C/W is theoretical θJB mounted to infinite heat sink. The larger number applies to module mounted to a 1.8 mm thick, 2P card using 1 oz. copper
power/gnd planes, with effective area for heat transfer of 75mm x 75mm.
The 750 incorporates a thermal management assist unit (TAU) composed of a thermal sensor, digital-to-ana-
log converter, comparator, control logic, and dedicated special-purpose registers (SPRs). See the 750 PPC
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 the table below.
.
Thermal Sensor Specifications
See Table “Recommended Operating Conditions,” on page 7, for operating conditions.
Num
Characteristic
Minimum
Maximum
Unit
°C
Notes
1
2
3
4
5
6
Temperature range
Comparator settling time
Resolution
0
20
4
128
—
—
.25
1
1
2
3
ms
°C
Drift, all sources
—
—
—
LSb
LSb
LSb
Linearity, error over range
Offset error, reducible
2
Note:
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.
Page 8
Version 1.51
PowerPC 740 and PowerPC 750 Datasheet
5/20/99
IBM [ IBM ]
