MSC8122 View Datasheet(PDF) - Freescale Semiconductor

Part Name

Description

Manufacturer

MSC8122

Quad Digital Signal Processor

Freescale Semiconductor 

Ordering Information

3.5 Thermal Considerations

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

TJ = TA + (RθJA × PD)

Eqn. 1

where

TA = ambient temperature near the package (°C)

RθJA = junction-to-ambient thermal resistance (°C/W)

PD = PINT + PI/O = power dissipation in the package (W)

PINT = IDD × VDD = internal power dissipation (W)

PI/O = power dissipated from device on output pins (W)

The power dissipation values for the MSC8122 are listed in Table 2-3. The ambient temperature for the device is the air

temperature in the immediate vicinity that would cool the device. The junction-to-ambient thermal resistances are JEDEC

standard values that provide a quick and easy estimation of thermal performance. 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. The value that more closely

approximates a specific application depends on the power dissipated by other components on the printed circuit board (PCB).

The value obtained using a single layer board is appropriate for tightly packed PCB configurations. The value obtained using a

board with internal planes is more appropriate for boards with low power dissipation (less than 0.02 W/cm2 with natural

convection) and well separated components. Based on an estimation of junction temperature using this technique, determine

whether a more detailed thermal analysis is required. Standard thermal management techniques can be used to maintain the

device thermal junction temperature below its maximum. If TJ appears to be too high, either lower the ambient temperature or

the power dissipation of the chip. You can verify the junction temperature by measuring the case temperature using a small

diameter thermocouple (40 gauge is recommended) or an infrared temperature sensor on a spot on the device case that is painted

black. The MSC8122 device case surface is too shiny (low emissivity) to yield an accurate infrared temperature measurement.

Use the following equation to determine TJ:

TJ = TT + (θJA × PD)

Eqn. 2

where

Note:

TT = thermocouple (or infrared) temperature on top of the package (°C)

θJA = thermal characterization parameter (°C/W)

PD = power dissipation in the package (W)

See MSC8102, MSC8122, and MSC8126 Thermal Management Design Guidelines (AN2601/D).

4 Ordering Information

Consult a Freescale Semiconductor sales office or authorized distributor to determine product availability and place an order.

Part

Package Type

MSC8122 Flip Chip Plastic Ball Grid Array (FC-PBGA)

Core

Voltage

1.1 V

1.2 V

Operating

Temperature

–40° to 105°C

–40° to 105°C

0° to 90°C

Core

Frequency

(MHz)

300

400

400

500

Order Number

Lead-Free

Lead-Bearing

MSC8122TVT4800V

MSC8122TVT6400V

MSC8122TVT6400

MSC8122VT8000

MSC8122TMP4800V

MSC8122TMP6400V

MSC8122TMP6400

MSC8122MP8000

MSC8122 Quad Digital Signal Processor Data Sheet, Rev. 15

Freescale Semiconductor

43

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