Design Considerations

The NE12S0A0V(H)20 uses a single phase and voltage mode controlled buck topology. The output can be trimmed in the range of 0.59Vdc to 5.1Vdc by a resistor from Trim pin to Ground.

The converter can be turned ON/OFF by remote control with positive on/off (ENABLE pin) logic. The converter DC output is disabled when the signal is driven low (below 0.3V). This pin is also used as the input turn on threshold judgment. Its voltage is percent of Input voltage during floating due to internal connection. So we do not suggest using an active high signal (higher than 0.8V) to turn on the module because this high level voltage will disable UVLO function. The module will turn on when this pin is floating and the input voltage is higher than the threshold.

The converter can protect itself by entering hiccup mode against over current and short circuit condition. Also, the converter will shut down when an over voltage protection is detected.

Safety Considerations

It is recommended that the user to provide a very fast-acting type fuse in the input line for safety. The output voltage set-point and the output current in the application could define the amperage rating of the fuse.

FEATURES DESCRIPTIONS

Enable (On/Off)

The ENABLE (on/off) input allows external circuitry to put the NE converter into a low power dissipation (sleep) mode. Positive ENABLE is available as standard. With the active high function, the output is guaranteed to turn on if the ENABLE pin is driven above 0.8V. The output will turn off if the ENABLE pin voltage is pulled below 0.3V

The ENABLE pin is also used as input UVLO function. Leaving the Enable floating, the module will turn on if the input voltage is higher than turn on threshold and turn off if the input voltage is lower than turn off threshold. The default Turn-on voltage is 4.3V with 1V Hysteresis.

The Turn-on voltage may be adjusted with a resistor placed between the “Enable” pin and “Ground” pin.

The formula for calculating the value of this resistor is:

VEN _ RTH	=	50 ⋅ (R + 18.2)	+ 1.5
		18.2 ⋅ R

VEN _ FTH	= VEN _ RTH − 1

Enable

NE20A

Fig. 18. Enable POR circuit.

VEN _ FTH	is the falling threshold
VEN _ RTH	is the rising threshold that you want.

R (Kohm) is the outen resistor that you connect from

Enable pin to the GND

Also, you will see an active high voltage will disable the input UVLO function

Preliminary DS_NE12S20A_07272007