Hi,
I am using a DC/DC converter to step down the voltage from 12V RMS to ~2.7V.
I am having trouble understanding this datasheet and its formulas.
I am trying to figure out how to set this component up to output 2.7VDC.
Can someone give me some pointers?
Attached is the link to the component from Digikey.
http://rohmfs.rohm.com/en/products/databook/datasheet/ic/power/switching_regulator/bd95861muv-e.pdf

Regards,
D.S.

 

The output voltage is set using the voltage divider resistor network from Vout to Vfb to ground. The internal voltage reference is 0.8V. To calculate this you can set up a proportion Vfb/Vout=R2/(R1+R2).
One note on this, the sum of the two resistors must be less that 50kohm due to reference bias currents. This reference feeds the internal error amplifier, saying when the output exceeds its nominal voltage, the feedback node exceeds the 0.8V and the switcher will convert the duty cycle as needed to compensate.
Hope this helps.

 

I would connect a pot from output. 19, & ground, 21,wiper to pin 20. Adjust to 2.7V. Replace with fixed values
if desired.