LP2952-N, LP2952A, LP2953, LP2953A

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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 k

Ω 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