ZHCSU09I July 2004 – February 2025 LP2981 , LP2981A
PRODUCTION DATA
The LP2981x is shut off by pulling the ON/OFF input low, and turned on by driving the input high. If this feature is not to be used, the ON/OFF input must be tied to VIN to keep the regulator on at all times (the ON/OFF input must not be left floating).
For proper operation, the signal source used to drive the ON/OFF input must be able to swing above and below the specified turn-on or turn-off voltage thresholds which specify an ON or OFF state (see the Electrical Characteristics).
The ON/OFF signal can come from either a totem-pole output, or an open-collector output with pullup resistor to the LP2981 and LP2891A input voltage or another logic supply. The high-level voltage can exceed the LP2981 and LP2891A input voltage, but must remain within the ratings list in the Absolute Maximum Ratings for the ON/OFF pin.