AD8565/AD8566/AD8567

Data Sheet

Rev. H | Page 10 of 13

This input current is not inherently damaging to the device as

long as it is limited to 5 mA or less. If a condition exists using

the AD8565/AD8566/AD8567 where the input exceeds the

supply more than 0.6 V, an external series resistor must be

added. The size of the resistor can be calculated by using the

maximum over-voltage divided by 5 mA. This resistance must

be placed in series with either input exposed to an overvoltage.

OUTPUT PHASE REVERSAL

The AD8565/AD8566/AD8567 are immune to phase reversal.

Although device output does not change phase, large currents

due to input overvoltage could damage the device. In applica-

tions where the possibility of an input voltage exceeding the

supply voltage exists, overvoltage protection must be used as

described in the Input Overvoltage Protection section.

POWER DISSIPATION

The maximum allowable internal junction temperature of

150°C limits the maximum power dissipation of AD8565/

AD8566/AD8567 devices. As the ambient temperature

increases, the maximum power dissipated by AD8565/AD8566/

AD8567 devices must decrease linearly to maintain maximum

junction temperature. If this maximum junction temperature is

exceeded momentarily, the device still operates properly once

the junction temperature is reduced below 150°C. If the

maximum junction temperature is exceeded for an extended

period, overheating could lead to permanent damage of the

device.

the following formula, the maximum power that an AD8565/

AD8566/AD8567 device can safely dissipate as a function of

temperature can be obtained:

where:

junction temperature (150°C).

junction-to-ambient.

The power dissipated by the device can be calculated as

where:

Figure 30 shows the maximum power dissipation vs. temper-

ature. To achieve proper operation, use the previous equation to

use Figure 30.

AMBIENT TEMPERATURE (°C)

1.25

0.75

0

–35

0.50

0.25

1.00

–15

5

25

45

65

85

16-LEAD LFCSP

5-LEAD SC70

8-LEAD MSOP

14-LEAD TSSOP

Figure 30. Maximum Power Dissipation vs. Temperature for 5-Lead SC70,

8-Lead MSOP, 14-Lead TSSOP, and 16-Lead LFCSP Packages

THERMAL PAD—AD8567

The AD8567 LFCSP comes with a thermal pad that is attached

to the substrate. This substrate is connected to the most positive

supply, that is, Pin 3 in the LFCSP package and Pin 4 in the

TSSOP package. To be electrically safe, the thermal pad must be

soldered to an area on the board that is electrically isolated or

adversely affects the performance of the part.

Soldering down this thermal pad dramatically improves the

heat dissipation of the package. It is necessary to attach vias that

connect the soldered thermal pad to another layer on the board.

This provides an avenue to dissipate the heat away from the

part. Without vias, the heat is isolated directly under the part.