The SD and OTW pins are both active-low, open-drain outputs. Their function is for protection-mode signaling to a PWM controller or other system-control device.

Any fault resulting in device shutdown, such as overtemperatue shut down, overcurrent shut-down, or undervoltage protection, is signaled by the SD pin going low. Likewise, OTW goes low when the device junction temperature exceeds 125°C (see Table 7-1).

TI recommends monitoring the OTW signal using the system microcontroller and responding to an OTW signal by reducing the load current to prevent further heating of the device resulting in device overtemperature shutdown (OTSD).

To reduce external component count, an internal pullup resistor to internal VREG (3.3 V) is provided on both SD and OTW outputs. Level compliance for 5-V logic can be obtained by adding external pullup resistors to 5 V (see the Electrical Characteristics section of this data sheet for further specifications).