Data Sheet

AD8045

Rev. C | Page 5 of 24

ABSOLUTE MAXIMUM RATINGS

Table 3.

Parameter

Rating

Supply Voltage

12.6 V

Power Dissipation

See Figure 4

Common-Mode Input Voltage

−VS − 0.7 V to +VS + 0.7 V

Differential Input Voltage

±VS

Exposed Paddle Voltage

−VS

Storage Temperature Range

−65°C to +125°C

Operating Temperature Range

−40°C to +125°C

Lead Temperature (Soldering 10 sec)

300°C

Junction Temperature

150°C

Stresses at or above those listed under Absolute Maximum

Ratings may cause permanent damage to the product. This is a

stress rating only; functional operation of the product at these

or any other conditions above those indicated in the operational

section of this specification is not implied. Operation beyond

the maximum operating conditions for extended periods may

affect product reliability.

THERMAL RESISTANCE

θJA is specified for the worst-case conditions; that is, θJA is specified

for the device soldered in the circuit board for surface-mount

packages.

Table 4. Thermal Resistance

Package Type

θJA

θJC

Unit

SOIC

80

30

°C/W

LFCSP

93

35

°C/W

Maximum Power Dissipation

The maximum safe power dissipation for the AD8045 is limited

by the associated rise in junction temperature (TJ) on the die. At

approximately 150°C, which is the glass transition temperature,

the properties of the plastic change. Even temporarily exceeding

this temperature limit may change the stresses that the package

exerts on the die, permanently shifting the parametric performance

of the AD8045. Exceeding a junction temperature of 175°C for

an extended period of time can result in changes in silicon devices,

potentially causing degradation or loss of functionality.

The power dissipated in the package (PD) is the sum of the

quiescent power dissipation and the power dissipated in the

die due to the AD8045 drive at the output. The quiescent

power is the voltage between the supply pins (VS) times the

quiescent current (IS).

PD = Quiescent Power + (Total Drive Power – Load Power)

(

)

L

2

OUT

L

OUT

S

S

S

D

R

V

–

R

V

2

V

I

V

P













×

+

×

=

RMS output voltages should be considered. If RL is referenced

to −VS, as in single-supply operation, the total drive power is

VS × IOUT. If the rms signal levels are indeterminate, consider

the worst case, when VOUT = VS/4 for RL to midsupply.

(

) (

)

L

S

S

S

D

R

/

V

I

V

P

2

4

+

×

=

In single-supply operation with RL referenced to −VS, worst case

is VOUT = VS/2.

Airflow increases heat dissipation, effectively reducing θJA. Also,

more metal directly in contact with the package leads and exposed

paddle from metal traces, through holes, ground, and power

planes reduces θJA.

Figure 4 shows the maximum safe power dissipation in the

package vs. the ambient temperature for the exposed paddle

SOIC (80°C/W) and LFCSP (93°C/W) package on a JEDEC

standard 4-layer board. θJA values are approximations.

AMBIENT TEMPERATURE (°C)

120

–40

–20

0

20

40

60

80

100

0.0

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

LFCSP

SOIC

Figure 4. Maximum Power Dissipation vs. Temperature for a 4-Layer Board

ESD CAUTION