JAJSHC9B May 2019 – October 2021 ALM2402F-Q1
The overtemperature and shutdown (OTF/SH_DN) pin is a bidirectional pin that allows both op amps to be put into a low IQ state (~500 µA) when forced low or less than VIL_OTF. As a result of this pin being bidirectional, and the respective enable and disable functionality, this pin must be pulled high or greater than VIH_OTF through a pullup resistor; see the Electrical Characteristics table.
When the junction temperature of ALM2402F-Q1 exceeds the limits specified in the Recommended Operating Conditions table, the OTF/SH_DN pin goes low to alert the application that both the outputs have turned off because of an overtemperature event. Also, the OTF pin goes low if VS_O1 and VS_O2 are 0 V. In case of an overtemperature event, the op amps are shut down even if OTF/SH_DN is forced high.
When OTF/SH_DN is pulled low and the op amps are shut down, the op amps are in an open loop, even when there is negative feedback applied. This occurrence is due to the loss of the open-loop gain in the op amps when the biasing is disabled. See Section 7.4.1 for more details on open- and closed-loop considerations.