Datasheet
IBM PowerPC 750GX RISC Microprocessor
DD1.X
Table 5-8. 750GX Heat-Sink Vendors
Company Names and Addresses for Heat-Sink Vendors
Chip Coolers, Inc.
333 Strawberry Field Rd.
Warwick, RI 02886
(800) 227-0254
http://www.chipcoolers.com
International Electronic Research Corporation (IERC)
413 North Moss Street
Burbank, CA 91502
(818) 842-7277
http://www.ctscorp.com/
Aavid Thermalloy
80 Commercial Street
Concord, NH 03301
(603) 224-9888
http://www.aavid.com
http://www.aavidthermalloy.com
Wakefield Thermal Solutions Inc.
33 Bridge Street
Pellham, NH 03076
(603) 635-2800
http://www.wakefield.com
5.7.1 Thermal Assist Unit
IBM recommends that the thermal assist unit (TAU) in these devices be calibrated before use. Calibration
methods are discussed in the IBM application note, Calibrating the Thermal Assist Unit in the
IBM25PPC750L Processors. Although this note was written for the 750L, the calibration methods discussed
in this document also apply to the 750GX.
5.7.2 Minimum Heat Sink Requirements
The worst-case power dissipation (PD) for the 750GX is shown in Table 3-5, Power Consumption for DD1.1,
on page 17. A conservative thermal management design will provide sufficient cooling to maintain the junc-
tion temperature (TJ) of the 750GX below 105°C at maximum PD and worst-case ambient temperature and
airflow conditions.
Many factors affect the 750GX power dissipation, including VDD, TJ, core frequency, process factors, and the
code that is running on the processor. In general, PD increases with increases in TJ, VDD, core frequency,
process variables, and the number of instructions executed per second.
For various reasons, a designer may determine that the power dissipation of the 750GX in their application
will be less than the maximum value shown in this datasheet. Assuming a lower PD will result in a thermal
management system with less cooling capacity than would be required for the maximum PD shown in the
datasheet. In this case, the designer may decide to determine the actual maximum 750GX PD in the partic-
ular application. Contact your IBM PowerPC field applications engineer for more information.
In addition to the system factors that must be considered in a cooling system analysis, three things should be
noted.
750GX_ds_body.fm SA14-2765-02
September 2, 2005
System Design Information
Page 63 of 73
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