LM9073T National Semiconductor, LM9073T Datasheet - Page 15

• Manufacturer Part Number: LM9073T
• Description: Dual High Current Low-Dropout System Regulator
• Manufacturer: National Semiconductor

Application Information
In the event that an oscillation is present, input bypassing
can also help de-tune the resonance. Figure 7 illustrates two
input bypassing approaches. The straight forward addition of
a larger valued electrolitic capacitor could suffice. In this
case however, if reverse battery connections are possibility it
is necessary to add a series protection diode as shown to
prevent damaging the polarized input capacitor.
An alternative input bypassing scheme is also shown. This
eliminates the use of polarized input capacitors and a series
protection diode. The values shown were derived empirically
in a representative typical application. Appropriate values for
any given application require experimentation.
Thermal Management
The LM9073 is packaged in both a TO-263 surface mount
power package and a narrow lead-pitch TO-220 package. To
Figure 8. Typical TO-263 PC Board Heatsinking
(Continued)
Figure 7. Input Bypassing
15
obtain operation over the highest possible load current and
input voltage ranges, care must be taken to control the oper-
ating temperature of the device. Thermal shutdown protec-
tion is built with a threshold above 150˚C Conventional heat
sinking techniques can be used with the TO-220 package.
When applying the TO-263 package on-board heat sinking is
important to prevent thermal shutdown. More copper foil
area under the tab of the device will directly reduce the oper-
ating junction temperature. Use of a double sided board with
vias between two planes of copper as shown in Figure 8 will
improve performance ad can optimize the PC board surface
area required.
DS101296-22
DS101296-23
www.national.com