Motorola CPCI-6115 manual Thermally Significant Components, Thermal Requirements, DDR Sdram

Thermal Requirements Hardware Preparation and Installation

This section provides systems integrators with information that can be used to conduct thermal evaluations of the board in their specific system configuration. It identifies thermally significant components and lists the corresponding maximum allowable component operating temperatures. It also provides sample procedures for component-level temperature measurements.

Table 2-3 on page 33 summarizes components that exhibit significant temperature rises. These are the components that should be monitored in order to assess thermal performance. The table also supplies the component reference designator and the maximum allowable operating temperature.

You can find components on the board by their reference designators as shown in Figure 2-1 on page 34. Versions of the board that are not fully populated may not contain some of these components.

The preferred measurement location for a component may be junction, case or air as specified in the table. Junction temperature refers to the temperature measured by an on-chip thermal device. Case temperature refers to the temperature at the top, center surface of the component. Air temperature refers to the ambient temperature near the component.

Table 2-3 Thermally Significant Components

		Maximum	Measurement
		Allowable	Location
		Temperature	(Junction, Case or
Component Location	General Description	(Degrees C)	Air)
U40	Ultra DMA PCI-IDE	70° C (158° F)	Air
U36	21555BB PCI Bridge	70° C (158° F)	Air
U32	MPC7457 Processor	103° C (217.4° F)	Case
U23, U89	DDR Clock Generator	85° C (185° F)	Air
U22	MV64360	110° C (230° F)	Case
U159, U160	32 megabit flash	85° C (185° F)	Air
U146	Clock Buffer	105° C (221° F)	Case
U13, U14	Cache	115° C (239° F)	Case
U2-U10, U74-U82	DDR SDRAM	70° C (158° F)	Air
U101, U102, U96	Ethernet PHY	120° C (248° F)	Case

CPCI-6115 CompactPCI Single Board Computer Installation and Use (6806800A68D) 33