MPC5200B(2006) Просмотр технического описания (PDF) - Freescale Semiconductor

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MPC5200B
(Rev.:2006)

SDRAM/DDR Memory Controller

Freescale Semiconductor 

Electrical and Thermal Characteristics

3.1.6 Thermal Characteristics

Table 7. Thermal Resistance Data

Rating

Board Layers

Sym Value Unit Notes SpecID

Junction to Ambient

Natural Convection

Single layer board

(1s)

RθJA

30

°C/W

(1),(2)

D6.1

Junction to Ambient

Natural Convection

Four layer board (2s2p)

RθJMA

22

°C/W

(1),(3)

D6.2

Junction to Ambient (@200 Single layer board

ft/min)

(1s)

RθJMA

24

°C/W

(1),(3)

D6.3

Junction to Ambient (@200 Four layer board

ft/min)

(2s2p)

RθJMA

19

°C/W

(1),(3)

D6.4

Junction to Board

Junction to Case

Junction to Package Top

Natural Convection

RθJB

RθJC

ΨJT

14

°C/W

(4)

8

°C/W

(5)

2

°C/W

(6)

D6.5

D6.6

D6.7

NOTES:

1 Junction temperature is a function of die size, on-chip power dissipation, package thermal resistance, mounting

site (board) temperature, ambient temperature, air flow, power dissipation of other components on the board, and

board thermal resistance.

2 Per SEMI G38-87 and JEDEC JESD51-2 with the single layer board horizontal.

3 Per JEDEC JESD51-6 with the board horizontal.

4 Thermal resistance between the die and the printed circuit board per JEDEC JESD51-8. Board temperature is

measured on the top surface of the board near the package.

5 Thermal resistance between the die and the case top surface as measured by the cold plate method (MIL

SPEC-883 Method 1012.1).

6 Thermal characterization parameter indicating the temperature difference between package top and the junction

temperature per JEDEC JESD51-2. When Greek letters are not available, the thermal characterization parameter

is written as Psi-JT.

3.1.6.1 Heat Dissipation

An estimation of the chip-junction temperature, TJ, can be obtained from the following equation:

TJ = TA+(RθJA × PD)

Eqn. 3

where:

TA = ambient temperature for the package (ºC)

RθJA = junction to ambient thermal resistance (ºC/W)

PD = power dissipation in package (W)

The junction to ambient thermal resistance is an industry standard value, which provides a quick and easy

estimation of thermal performance. Unfortunately, there are two values in common usage: the value

determined on a single layer board, and the value obtained on a board with two planes. For packages such

as the PBGA, these values can be different by a factor of two. Which value is correct depends on the power

dissipated by other components on the board. The value obtained on a single layer board is appropriate for

the tightly packed printed circuit board. The value obtained on the board with the internal planes is usually

appropriate if the board has low power dissipation and the components are well separated.

MPC5200B Data Sheet, Rev. 1

Freescale Semiconductor

11

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