datasheet question - what does this mean?

[ethrbunny]

from the winbond-usa site on the ISD2560:

(page 7) its referring the the Vcca and Vccd pins:

"These voltage busses are brought out to separate pins and should be tied together as close to the supply as possible. In addition these supplies should be decoupled as close to the package as possible."

I think I get the first sentence but am stymied by the second.

... still fighting a noise problem with my phrase recorder. I tried grounding the input pin. Same noise, still there on playback. This makes me believe that either my chip is not properly powered / grounded.

[The Tone God]

Vcca and Vccd are for analog and digital power supply respectively. The decoupling is usually in the form of a decoupling cap, 0.01uf or more, tied from the power pin to ground as close as physically possible to the IC itself. Its a fairly common practice with digital ICs.

Andrew

[ethrbunny]

Dang. Looks like my circuit has .1u between those pins and ground. Does it matter if the cap is NP?

[The Tone God]

Nope. Typically the cap is ceramic or poly. 0.01uF - 0.1uF is common. I stress the "as close as possible to the IC" part.

Andrew