NCV8508

http://onsemi.com

10

APPLICATION NOTES

Calculating Power Dissipation in a Single Output

Linear Regulator

The maximum power dissipation for a single output

regulator (Figure 19) is:

PD(max) + [VIN(max) * VOUT(min)]IOUT(max)

(1)

) VIN(max)IQ

where:

application, and

SMART

REGULATOR

®

Control

Features

Figure 19. Single Output Regulator with Key

Performance Parameters Labeled

}

R

qJA +

150

°C * TA

PD

(2)

package section of the data sheet. Those packages with

the die temperature below 150

°C.

In some cases, none of the packages will be sufficient to

dissipate the heat generated by the IC, and an external

heatsink will be required.

Figure 20. 16 Lead SOW (4 Leads Fused),

qJA as

a Function of the Pad Copper Area (2 oz. Cu

Thickness), Board Material = 0.0625

, G−10/R−4

40

70

90

100

0

0.5

1.0

1.5

2.0

3.0

80

60

50

2.5

Heatsinks

A heatsink effectively increases the surface area of the

package to improve the flow of heat away from the IC and

into the surrounding air.

Each material in the heat flow path between the IC and the

outside environment will have a thermal resistance. Like

series electrical resistances, these resistances are summed to

R

qJA + RqJC ) RqCS ) RqSA

(3)

where:

functions of the package type, heatsink and the interface

between them. These values appear in heatsink data sheets

of heatsink manufacturers.

ORDERING INFORMATION

Device

Output Voltage

Package

Shipping†

NCV8508DW50

5.0 V

SO−16L

47 Units / Rail

NCV8508DW50G

5.0 V

SO−16L

(Pb−Free)

47 Units / Rail

NCV8508DW50R2

5.0 V

SO−16L

1000 / Tape & Reel

NCV8508D2T50

5.0 V

50 Units / Rail

NCV8508D2T50G

5.0 V

(Pb−Free)

50 Units / Rail

NCV8508D2T50R4

5.0 V

750 / Tape & Reel

†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging

Specifications Brochure, BRD8011/D.