5
Application Information
(Refer to Application Note AN552 for Further Information)
The Intersil HA-2542 is a state of the art monolithic device
which also approaches the “ALL-IN-ONE” amplifier concept.
This device features an outstanding set of AC parameters
augmented by excellent output drive capability providing for
suitable application in both high speed and high output drive
circuits.
Primarily intended to be used in balanced 50
and 75
coaxial cable systems as a driver, the HA-2542 could also be
used as a power booster in audio systems as well as a
power amp in power supply circuits. This device would also
be suitable as a small DC motor driver.
The applications shown in Figures 2 through Figure 4
demonstrate the HA-2542 at gains of +100 and +2 and as a
video cable driver for small signals.
Power Dissipation Considerations
At high output currents, especially with the PDIP package,
care must be taken to ensure that the Maximum Junction
Temperature (T
J
, see “Absolute Maximum Ratings” table) is
not exceeded. As an example consider the HA-2542 in the
PDIP package, with a required output current of 20mA at
V
OUT
= 5V. The power dissipation is the quiescent power
(1.2W = 30V x 40mA) plus the power dissipated in the
output stage (P
OUT
= 200mW = 20mA x (15V - 5V)), or a
total of 1.4W. The thermal resistance (
θ
JA
) of the PDIP
package is 100
o
C/W, which increases the junction
temperature by 140
o
C over the ambient temperature (T
A
).
Remaining below T
JMAX
requires that T
A
be restricted to
≤
10
o
C (150
o
C - 140
o
C). Heatsinking would be required for
operation at ambient temperatures greater than 10
o
C.
Note that the problem isn’t as severe with the CERDIP
package due to it’s lower thermal resistance, and higher
T
JMAX
. Nevertheless, it is recommended that Figure 1 be
used to ensure that heat sinking is not required.
Allowable output power can be increased by decreasing the
quiescent dissipation via lower supply voltages.
For more information please refer to Application Note
AN556, “Thermal Safe Operating Areas for High Current Op
Amps”.
Prototyping Guidelines
For best overall performance in any application, it is
recommended that high frequency layout techniques be
used. This should include: 1) mounting the device through a
ground plane: 2) connecting unused pins (NC) to the ground:
3) mounting feedback components on Teflon standoffs and
or locating these components as close to the device as
possible: 4) placing power supply decoupling capacitors
from device supply pins to ground.
OUTPUT CURRENT (100% DUTY CYCLE, mA)
M
A
o
C
0
5
10
15
20
25
30
35
40
45
50
0
20
40
60
80
100
120
CERDIP
PDIP
V
OUT
=
±
5V
V
S
=
±
15V
FIGURE 1. MAXIMUM OPERATING TEMPERATURE vs
OUTPUT CURRENT
HA-2542