AS1100 datasheet(10/12 Pages) AMSCO

10 / 12 page

Data Sheet AS1100

Revision 1.32, Oct. 2004

Page 10 of 12

Computing Power Dissipation

The upper limit for power dissipation (PD) for the AS1100 is determined from the following equation:

PD = (VDD x 0.5mA) + (VDD - VLED)(DUTY x ISEG x N)

where:

VDD = supply voltage

DUTY = duty cycle set by intensity register

N = number of segments driven (worst case is 8)

VLED = LED forward voltage

ISEG = segment current set by RSET

Dissipation Example:

ISEG = 40mA, N = 8, DUTY = 31/32, VLED = 1.8V at 40mA, VDD = 5.25V

PD = 5.25V(0.5mA) + (5.25V - 1.8V)(31/32 x 40mA x 8) = 1.07W

Thus, for a PDIP package

θJA = +75°C/W (from Table 13), the maximum allowed ambient temperature TA is given by:

TJ,MAX = TA + PD x

θJA = 150°C = TA +1.07W x 75°C/W.

where TA = +69.7°C.

The TA limit for SO Packages in the dissipation example above is +59.0°C.

Package Information

Inches

Millimeters

Dim Min

Max

Min

Max

0.093 0.104 2.35

2.65

A1 0.004 0.012 0.10

0.30

0.014 0.019 0.35

0.49

C 0.009 0.013 0.23

0.32

D 0.598 0.614 15.20

15.60

0.050

1.27

0.291 0.299 7.40

7.60

H 0.394 0.419 10.00

10.65

0.016 0.050 0.40

1.27

Figure 4: SOIC-24 package dimensions

AS1100 Datasheet(PDF) 10 Page - ams AG

AS1100 Datasheet(HTML) 10 Page - ams AG

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12

Datasheet Download

Link URL