Datasheet AD8565, AD8566, AD8567 (Analog Devices) - 10

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AD8565/AD8566/AD8567 Data Sheet
This input current is not inherently damaging to the device as The power dissipated by the device can be calculated as long as it is limited to 5 mA or less. If a condition exists using PDISS = (VS − VOUT) × ILOAD the AD8565/AD8566/AD8567 where the input exceeds the supply more than 0.6 V, an external series resistor must be where: added. The size of the resistor can be calculated by using the VS is the supply voltage. maximum over-voltage divided by 5 mA. This resistance must VOUT is the output voltage. be placed in series with either input exposed to an overvoltage. ILOAD is the output load current.
OUTPUT PHASE REVERSAL
Figure 30 shows the maximum power dissipation vs. temper- ature. To achieve proper operation, use the previous equation to The AD8565/AD8566/AD8567 are immune to phase reversal. calculate PDISS for a specific package at any given temperature or Although device output does not change phase, large currents use Figure 30. due to input overvoltage could damage the device. In applica-
1.25
tions where the possibility of an input voltage exceeding the supply voltage exists, overvoltage protection must be used as
16-LEAD LFCSP
described in the Input Overvoltage Protection section.
W) ( 1.00 POWER DISSIPATION TION A P 0.75 14-LEAD TSSOP
The maximum allowable internal junction temperature of
ISSI D 8-LEAD MSOP
150°C limits the maximum power dissipation of AD8565/
ER W
AD8566/AD8567 devices. As the ambient temperature
O 0.50 5-LEAD SC70
increases, the maximum power dissipated by AD8565/AD8566/
M P MU
AD8567 devices must decrease linearly to maintain maximum
XI 0.25
junction temperature. If this maximum junction temperature is
MA
exceeded momentarily, the device still operates properly once
0
the junction temperature is reduced below 150°C. If the
–35 –15 5 25 45 65 85
030 maximum junction temperature is exceeded for an extended
AMBIENT TEMPERATURE (°C)
01909- period, overheating could lead to permanent damage of the Figure 30. Maximum Power Dissipation vs. Temperature for 5-Lead SC70, 8-Lead MSOP, 14-Lead TSSOP, and 16-Lead LFCSP Packages device.
THERMAL PAD—AD8567
The maximum safe junction temperature, TJMAX, is 150°C. Using the following formula, the maximum power that an AD8565/ The AD8567 LFCSP comes with a thermal pad that is attached AD8566/AD8567 device can safely dissipate as a function of to the substrate. This substrate is connected to the most positive temperature can be obtained: 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 PDISS = TJMAX − TA/θJA soldered to an area on the board that is electrically isolated or where: connected to VDD. Attaching the thermal pad to ground PDISS is the AD8565/AD8566/AD8567 power dissipation. adversely affects the performance of the part. TJMAX is the AD8565/AD8566/AD8567 maximum allowable Soldering down this thermal pad dramatically improves the junction temperature (150°C). heat dissipation of the package. It is necessary to attach vias that TA is the ambient temperature of the circuit. connect the soldered thermal pad to another layer on the board. θJA is the AD8565/AD8566/AD8567 package thermal resistance, This provides an avenue to dissipate the heat away from the junction-to-ambient. part. Without vias, the heat is isolated directly under the part. Rev. H | Page 10 of 13 Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION PIN CONFIGURATIONS TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ELECTRICAL CHARACTERISTICS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION INPUT OVERVOLTAGE PROTECTION OUTPUT PHASE REVERSAL POWER DISSIPATION THERMAL PAD—AD8567 TOTAL HARMONIC DISTORTION + NOISE (THD + N) SHORT-CIRCUIT OUTPUT CONDITIONS LCD PANEL APPLICATIONS OUTLINE DIMENSIONS ORDERING GUIDE