ADV7152LS85 datasheet(31/32 Pages) AD

31 / 32 page

ADV7152

–31–

REV. B

APPENDIX 7

THERMAL AND ENVIRONMENTAL CONSIDERATIONS

Table A. Thermal Characteristics vs. Airflow

Air Velocity

100

200

(Linear feet/min)

(Still Air)

JA (°C/W)

No Heatsink

EG&G D10100-28 Heatsink 32

Thermalloy 2290 Heatsink

Thermal Model

The junction temperature of the device in a specific application

is given by:

TJ = TA + PD (θJC + θCA)

(1)

TJ = TA + PD (

JA)

(2)

where:

TJ = Junction Temperature of Silicon (°C)

TA = Ambient Temperature (

°C)

PD = Power Dissipation (W)

JC = Junction to Case Thermal Resistance (°C/W)

CA = Case to Ambient Thermal Resistance (

°C/W)

JA = Junction to Ambient Thermal Resistance (

°C/W)

Package Enhancements

The standard QFP package has been enhanced to a PowerQuad2

package. This supports an improved thermal performance come

pared to standard QFP. In this case, the die is attached to

heatslug so that the power that is dissipated can be conducted to

the external surface of the package. This provides a highly effi-

cient path for the transfer of heat to the package surface. The

package configuration also provides an efficient thermal path

from the ADV7152 to the Printed Circuit Board via the leads.

Heatsinks

The maximum silicon junction temperature should be limited to

100

°C. Temperatures greater than this will reduce long term

device reliability. To ensure that the silicon junction tempera-

ture stays within prescribed limits, the addition of an external

heatsink may be necessary. Heatsinks, will reduce

JA as shown

in the “Thermal Characteristics vs. Airflow” table.

The ADV7152 is a very highly integrated monolithic silicon

device. This high level of integration, in such a small package,

inevitably leads to consideration of thermal and environmental

conditions in which the ADV7152 must operate. Reliability of

the device is significantly enhanced by keeping it as cool as pos-

sible. In order to avoid destructive damage to the device, the

absolute maximum junction temperature of 150

°C must never

be exceeded. Certain applications, depending on pixel data

rates, may require forced air cooling, or external heatsinks. The

following data is intended as a guide in evaluating the operating

conditions of a particular application so that optimum device

and system performance is achieved.

It should be noted that information on package characteristics pub-

lished herein may not be the most up to date at the time of reading

this. Advances in package compounds and manufacture will inevita-

bly lead to improvements in the thermal data. Please contact your

local sales office for the most up-to-date information.

Power Dissipation

The diagram shows graphs of power dissipation in watts vs.

pixel clock frequency for the ADV7152.

1.50

0.75

0.50

1.25

1.00

AA = +5V

REF = +1.2V

A = 25°C

180

160

140

120

100

PIXEL CLOCK FREQUENCY – MHz

200

220

THE "TYPICAL ON-SCREEN PATTERN" CORRESPONDS TO LINEAR CHANGES IN THE

PIXEL INPUT (I. E., A BLACK TO WHITE RAMP). IN GENERAL, COLOR IMAGES TEND TO

APPROXIMATE THIS CHARACTERISTIC.

Typical Power Dissipation vs. Pixel Rate

Package Characteristics

The table of thermal characteristics shows typical information

for the ADV7152 (100-Lead Plastic Power QFP) using various

values of Airflow.

Junction to Case (

JC) Thermal Resistance for this particular

part is:

JC (100-Lead Plastic Power QFP) = 1.0

°C/W

(Note: 0

°C is independent of airflow.)

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