ZHCS547K January 2010 – February 2018 LM27402
PRODUCTION DATA.
The EN pin of the LM27402 allows the output to be toggled on and off and is a precision analog input. When the EN voltage exceeds 1.17 V, the controller initiates the soft-start sequence as long as the input voltage and sub-regulated voltage have exceeded their UVLO thresholds of 2.9 V. The EN pin has an absolute maximum voltage rating of 6.0 V and should not exceed the voltage on VDD. There is an internal 2 µA pullup current source connected to the EN pin. If EN is open, the LM27402 turns on automatically if VIN and VDD exceed 2.9 V. If the EN voltage is held below 0.8 V, the LM27402 enters a deep shutdown state where the internal bias circuitry is off. The quiescent current is approximately 35 µA in deep shutdown. The EN pin has 100 mV of hysteresis to reject noise and allow the pin to be resistively coupled to the input voltage or sequenced with other rails.