LP2953_15 Datasheet, PDF (21/41 Pages) Texas Instruments – LP295x Adjustable Micropower Low-Dropout Voltage Regulators

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LP2952-N, LP2952A, LP2953, LP2953A
SNVS095F – MAY 2004 – REVISED MARCH 2015
Application Information (continued)
8.1.8 Auxiliary Comparator (LP2953 Only)
The LP2953 contains an auxiliary comparator whose inverting input is connected to the 1.23-V reference. The
auxiliary comparator has an open-collector output whose electrical characteristics are similar to the dropout
detection comparator. The noninverting input and output are brought out for external connections.
8.1.9 SHUTDOWN Input
A logic-level signal will shut off the regulator output when a low (< 1.2 V) is applied to the SHUTDOWN input.
To prevent possible mis-operation, the SHUTDOWN input must be actively terminated. If the input is driven from
open-collector logic, a pullup resistor (20 kΩ to 100 kΩ is recommended) should be connected from the
SHUTDOWN input to the regulator input.
If the SHUTDOWN input is driven from a source that actively pulls high and low (like an op-amp), the pullup
resistor is not required, but may be used.
If the shutdown function is not to be used, the cost of the pullup resistor can be saved by simply tying the
SHUTDOWN input directly to the regulator input.
NOTE
Because the Absolute Maximum Ratings state that the SHUTDOWN input can not go
more than 0.3 V below ground, the reverse battery-input protection feature which protects
the regulator input is sacrificed if the SHUTDOWN input is tied directly to the regulator
input.
If reverse-battery input protection is required in an application, the pullup resistor between the SHUTDOWN input
and the regulator input must be used.
8.2 Typical Applications
8.2.1 Basic 5-V Regulator
Figure 33. Basic 5-V Regulator
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Product Folder Links: LP2952-N LP2952A LP2953 LP2953A