Quote:
Originally Posted by ramirami
... By this information I need two levels of voltage 3.3V for Pin no. 20 to power up the circuit. and another voltage of 1.8V for Pin no. 4 for output levels.
Do you think it should work?
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It looks like it should work. They recommend using voltage regulators to get the 3.3v and 1.8v.
A very simple non-critical low-current voltage regulator can be made from an LED (which acts as a zener diode) and a current-limiting resistor. Red LEDs have a forward voltage drop of 1.7v to 1.9v depending on their brightness rating. This range should be fine for the 1.8v needed. Other color LEDs such as green or blue (but not bright blue) have a forward voltage drop of 3.4v, which should be fine for the 3.3v supply. Or, two (not very bright) red LEDs in series would give about 3.4v, which should be okay too. You need to supply the LEDs with voltage from 5v or so (which you can get from the USB power pins) through a current-limiting resistor (1K to 10K is typical). A lower resistance gives higher brightness but uses more current and is not need for this application.
Read more about LED voltage drops here:
http://www.theledlight.com/LED101.html