MPC852T datasheet(10/80 Pages) FREESCALE

10 / 80 page

MPC852T Hardware Specifications, Rev. 3.1

Freescale Semiconductor

References

7.5 Experimental Determination

To determine the junction temperature of the device in the application after prototypes are available, the thermal

characterization parameter ( JT) can be used to determine the junction temperature with a measurement of the

temperature at the top center of the package case using the following equation:

TJ = TT +( JT x PD)

where:

JT = thermal characterization parameter

TT = thermocouple temperature on top of package

PD = power dissipation in package

The thermal characterization parameter is measured per JESD51-2 specification published by JEDEC using a

40-gauge type T thermocouple epoxied to the top center of the package case. The thermocouple should be positioned

so that the thermocouple junction rests on the package. A small amount of epoxy is placed over the thermocouple

junction and over about 1 mm of wire extending from the junction. The thermocouple wire is placed flat against the

package case to avoid measurement errors that cooling effects of the thermocouple wire cause.

References

Semiconductor Equipment and Materials International(415) 964-5111

805 East Middlefield Rd

Mountain View, CA 94043

MIL-SPEC and EIA/JESD (JEDEC) specifications800-854-7179 or

(Available from Global Engineering documents)303-397-7956

JEDEC Specifications http://www.jedec.org

1. C.E. Triplett and B. Joiner, “An Experimental Characterization of a 272 PBGA Within an Automotive Engine

Controller Module,” Proceedings of SemiTherm, San Diego, 1998, pp. 47-54.

2. B. Joiner and V. Adams, “Measurement and Simulation of Junction to Board Thermal Resistance and Its

Application in Thermal Modeling,” Proceedings of SemiTherm, San Diego, 1999, pp. 212-220.

Power Supply and Power Sequencing

This section provides design considerations for the MPC852T power supply. The MPC852T has a core voltage

(VDDL) and PLL voltage (VDDSYN) that operates at a lower voltage than the I/O voltage VDDH. The I/O section of

the MPC852T is supplied with 3.3 V across VDDH and VSS (GND).

The signal PA[0:3], PA[8:11], PB15, PB[24:25]; PB[28:31], PC[4:7], PC[12:13], PC15] PD[3:15], TDI, TDO, TCK,

TRST, TMS, MII_TXEN, MII_MDIO are 5 V-tolerant. All inputs cannot be more than 2.5 V greater than VDDH. In

addition, 5 V-tolerant pins can not exceed 5.5 V, and remaining input pins cannot exceed 3.465 V. This restriction

applies to power-on reset or power down and normal operation.

MPC852T Arkusz danych(PDF) 10 Page - Freescale Semiconductor, Inc