ada4938-2 Analog Devices, Inc., ada4938-2 Datasheet - Page 7

• Manufacturer Part Number: ada4938-2
• Description: Ultralow Distortion Differential Adc Driver
• Manufacturer: Analog Devices, Inc.

Preliminary Technical Data
ABSOLUTE MAXIMUM RATINGS
Table 5.
Parameter
Supply Voltage
Power Dissipation
Storage Temperature Range
Operating Temperature Range
Lead Temperature (Soldering, 10 sec)
Junction Temperature
Stresses above those listed under Absolute Maximum Rating
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
THERMAL RESISTANCE
θ
to a high thermal conductivity 4-layer circuit board, as described in
EIA/JESD 51-7. The exposed pad is not electrically connected to
the device. It is typically soldered to a pad on the PCB that is
thermally and electrically connected to an internal ground plane.
Table 6. Thermal Resistance
Package Type
24-Lead LFCSP (Exposed Pad)
Maximum Power Dissipation
The maximum safe power dissipation in the ADA4938 package
is limited by the associated rise in junction temperature (T
the die. At approximately 150°C, which is the glass transition
temperature, the plastic changes its properties. Even temporarily
exceeding this temperature limit can change the stresses that the
package exerts on the die, permanently shifting the parametric
performance of the ADA4938. Exceeding a junction
temperature of 150°C for an extended period can result in
changes in the silicon devices, potentially causing failure.
JA
is specified for the device (including exposed pad) soldered
θ
65
JA
Rating
12 V
See Figure 3
−65°C to +125°C
−40°C to +85°C
300°C
150°C
Unit
°C/W
J
) on
Rev. PrB | Page 7 of 23
The power dissipated in the package (P
quiescent power dissipation and the power dissipated in the
package due to the load drive. The quiescent power is the
voltage between the supply pins (V
current (I
upon the particular application. The power due to load drive is
calculated by multiplying the load current by the associated
voltage drop across the device. RMS voltages and currents must
be used in these calculations.
Airflow increases heat dissipation, effectively reducing θ
addition, more metal directly in contact with the package
leads/exposed pad from metal traces, through-holes, ground,
and power planes reduces the θ
Figure 3 shows the maximum safe power dissipation in the
package vs. the ambient temperature for the 24-lead LFCSP
(65°C/W) on a JEDEC standard 4-layer board.
ESD CAUTION
Figure 3. Maximum Power Dissipation vs. Temperature for a 4-Layer Board
S
). The power dissipated due to the load drive depends
JA
.
S
) times the quiescent
D
) is the sum of the
ADA4938-2
JA
. In