PRODUCT SPECIFICATION

FAN1582

REV. 1.1.2 2/26/03

7

istics section provides a separate thermal resistance and

maximum junction temperature for both the control circuitry

and the power transistor. Calculate the maximum junction

temperature for both sections to ensure that both thermal

limits are met.

For example, look at using an FAN1582M-1.5 to generate

3A @ 1.5V ± 2% from a 3.3V source (3.2V to 3.6V).

Assumptions:

•

thermally conductive material)

The power dissipation in this application is:

From the specification table,

= 70 + (6.39) * (5 + 3) = 121°C

The junction temperature is below the maximum rating.

Junction-to-case thermal resistance is specified from the IC

junction to the bottom of the case directly below the die. This

is the lowest resistance path for heat flow. Proper mounting

ensures the best thermal flow from this area of the package to

the heat sink. Use of a thermally conductive material at the

case-to-heat sink interface is recommended. Use a thermally

conductive spacer if the case of the device must be electri-

cally isolated and include its contribution to the total thermal

resistance.

Figure 3. Application Circuit (FAN1582)

Table 1. Bill of Materials for Application Circuit for the FAN1582

Item

Quantity

Manufacturer

Part Number

Description

C1, C3

2

Xicon

L10V10

10µF, 10V Aluminum

C2

1

Xicon

L10V100

100µF, 10V Aluminum

C4

1

Any

1µF Ceramic

R1

1

Generic

124

Ω, 1%

R2

1

Generic

86.6

Ω, 1%

U1

1

Fairchild

FAN1582P

3A Regulator

100

µF

C2

10

µF

C3

2.1V at 3A

+

10

µFC1

1

µF

C4

+

Adj

FAN1582

86.6

Ω

124

Ω

R2

R1

U1