It's nice to have the part no.
I have 0808 but it's 8 channel parallel.
I know 8051's becoming obsolete but it is still serving my purpose.
The day when i'll see that i need more, i'll switch to newer familiy ver of the same. I am looking for ds32008 series. R U aware ot the same? If Y PLS tell me more bout that.
The ADC0804 is a nice part, but has a parallel interface. One thing you didn't mention was the speed you wanted to run the A/D conversions at.
If your application can make do with fairly slow conversions, here are two inexpensive designs from EDN that make use of a micro's hardware timer to help make the conversions.
The first is a single-slope design, the second uses a dual-slope approach and provides good accuracy for such a simple circuit. Both circuits burden the micro with more work than a self-contained ADC, but keep your costs down.
If you want a complete single-chip 12-bit ADC, you might try Microchip's MPC3221, a very low power A/D with an I2C interface. It's available from Digi-Key for ~ $2.