ADA4857-1/ADA4857-2

Data Sheet

Rev. D | Page 6 of 21

ABSOLUTE MAXIMUM RATINGS

Table 3.

Parameter

Rating

Supply Voltage

11 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 device soldered in circuit board for surface-mount packages.

Table 4.

Package Type

θJA

θJC

Unit

8-Lead SOIC

115

15

°C/W

8-Lead LFCSP

94.5

34.8

°C/W

16-Lead LFCSP

68.2

19

°C/W

MAXIMUM POWER DISSIPATION

The maximum safe power dissipation for the ADA4857 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 ADA4857. Exceeding a junction temperature of

175°C for an extended period 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 ADA4857 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

OUT

L

OUT

S

S

S

D

R

V

R

V

V

I

V

P

2

–

2













×

+

×

=

RMS output voltages must 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, the worst

case is VOUT = VS/2.

Airflow increases heat dissipation, effectively reducing θJA.

In addition, 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 power dissipation in the package

vs. the ambient temperature for the SOIC and LFCSP packages

on a JEDEC standard 4-layer board. θJA values are approximations.

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

ESD CAUTION

0

0.5

1.0

1.5

2.0

2.5

3.0

–40 –30 –20 –10 0 10 20 30 40 50 60 70 80 90 100 110 120

AMBIENT TEMPERATURE (°C)

ADA4857-1 (SOIC)

ADA4857-1 (LFCSP)

ADA4857-2 (LFCSP)