LP3990MF-0.8 National Semiconductor, LP3990MF-0.8 Datasheet - Page 11

• Manufacturer Part Number: LP3990MF-0.8
• Description: 150mA Linear Voltage Regulator for Digital Applications
• Manufacturer: National Semiconductor

Application Hints
tantalum will increase about 2:1 as the temperature goes
from 25˚C down to -40˚C, so some guard band must be
allowed.
ENABLE CONTROL
The LP3990 features an active high Enable pin, V
turns the device on when pulled high. When not enabled the
regulator output is off and the device typically consumes
2nA.
If the application does not require the Enable switching
feature, the V
regulator output permanently on.
To ensure proper operation, the signal source used to drive
the V
specified turn-on/off voltage thresholds listed in the Electrical
Characteristics section under V
EN
input must be able to swing above and below the
EN
pin should be tied to V
IL
(Continued)
and V
IH
.
IN
to keep the
EN
, which
11
Micro SMD MOUNTING
The micro SMD package requires specific mounting tech-
niques, which are detailed in National Semiconductor Appli-
cation Note AN-1112.
For best results during assembly, alignment ordinals on the
PC board may be used to facilitate placement of the micro
SMD device.
Micro SMD LIGHT SENSITIVITY
Exposing the micro SMD device to direct light may affect the
operation of the device. Light sources, such as halogen
lamps, can affect electrical performance, if placed in close
proximity to the device.
Light with wavelengths in the infra-red portion of the spec-
trum is the most detrimental, and so, fluorescent lighting
used inside most buildings, has little or no effect on perfor-
mance.
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