MC34063 fixed different outputs for variable input

I want to design a dc to dc converter sing MC34063 for following :

Vin ( min) = 5V
Vout max = 25V

Iout(max)= 1.5A

Output:

Vout1= 5V
Vout2= 12V
Vout3= 15V
Vout4= Adjustable

I want to get these outputs by changing resistor value ( using rotary encoder ) from single circuit . does it possible ?

You might not be able to do this with one value of inductor.

http://www.nomad.ee/micros/mc34063a/

A rotary encoder is not a potentiometer, it does not change resistance. A rotary encoder gives digital outputs as it's turned (ie, pins go low or high in a pattern that tells you both speed and direction).

For this, you need a potentiometer.

Or are you talking about using a microcontroller + rotary encoder to select one of three settings?

Its not possible just using an MC34063 because your output requirement of 1.5 A exceeds the chips current rating.
You would need an external switch either a transistor or fet.
Also, the inductor value is going to be difficult to meet for all the requirements .

What the others have said regarding needing different inductors and not exceeding the chip's 1.5A limit are right, so getting that range of output values is not practical.
All the same, for general use, I just thought I'd give you a link to a calculator for the MC34063A. A handy tool:-
MC34063A development aid

Yeah, I kinda gave that already.

There used to be a much better calculator online, but it has disappeared. It allowed you to enter a range of input voltages as a center voltage and +- percentage.

polymorph:
Yeah, I kinda gave that already.

http://forum.arduino.cc/index.php?topic=369846.msg2550610#msg2550610

There used to be a much better calculator online, but it has disappeared. It allowed you to enter a range of input voltages as a center voltage and +- percentage.

Sorry, I missed that.