Post by thread:ISD chip Vcc?

PICers, I've been looking at the ISD 33000 voice player chip. It's OK but needs a 3V supply & 3V regs are awkward to get ahold of. Anybody know how critical the 3V limit is? The data sheet is a bit obscure but there is a test cct shown operating on 3.3V. Just wondering if using 3 diodes to drop the Vcc would be OK? It's just that Vcc then becomes a little uncertain for different diodes. Would that upset things? Thnax - PJH

PJH wrote: > I've been looking at the ISD 33000 voice player chip. It's OK but > needs a 3V supply & 3V regs are awkward to get ahold of. Eh? I don't believe it! LM317s are cheap as chips. Unless you want really really low power regs. > Anybody know how critical the 3V limit is? ... Just wondering if > using 3 diodes to drop the Vcc would be OK? It's just that Vcc then > becomes a little uncertain for different diodes. Would that upset > things? I imagine it's OK, I suggest give it a go. Variation between diodes will be quite small actually. I'll bet you get very close to 3V if starting from 5V. But really, why not use an LM317? -- Cheers, Paul B.

--- PJH <spam_OUTelekTakeThisOuTNETSTRA.COM.AU> scritto: > The data sheet is a bit obscure but > there is a test cct shown operating > on 3.3V. Just wondering if using 3 > diodes to drop the Vcc would be OK? only if the current is costant.... elsewere the vcc is NOT ok. You can also use a zener, or not? :-) but a VR like 317 can function ok :-) > It's just that Vcc then becomes a > little uncertain for different > diodes. Would that upset things? it is NOT good practice to have vcc NOT regulated === Giacomo Schieppati, e-mail: .....gschieppatiKILLspam@spam@yahoo.it e-mail URGENTI: gschieppatiKILLspami.am e-mail alcooliche: .....giacKILLspam.....beer.com ICQ: 34514036 ______________________________________________________________________ DO YOU YAHOO!? Il tuo indirizzo gratis e per sempre @yahoo.it su http://mail.yahoo.it

Hi, We were faced with the same issue. I believe that we went with 3.3 volts and I tried for many, many, weeks to get ISD to sign up to 3.5 volts. They would not commit. They did some testing and tap dancing and finally would not commit. Certainly it was OK for breadboard, demo boards, etc. If you look at their programming board, I believe that they used 3.3 volts. We put down two surface mount pads for varying pin assignment layouts just in case of availability issues. Ended up with Mot SOT-89 package. Craig >PICers, > >I've been looking at the ISD 33000 >voice player chip. It's OK but >needs a 3V supply & 3V regs are >awkward to get ahold of. Anybody >know how critical the 3V limit is? >

As I recall, the datasheet lists limits on Vcc. In my application, I used a MAX882CP with a 1.5M and 1M (both 1%) voltage divider in the feedback. This drove both a PIC16c61 and an ISD4003. This was battery powered with three AA cells in series along with a 1N5817 for reverse polarity detection. The audio power amp (TPA7010) was run off the regulator INPUT voltage while everything else was run off the regulated +3V. Harold Harold Hallikainen EraseMEharoldspam_OUTTakeThisOuThallikainen.com Hallikainen & Friends, Inc. See the FCC Rules at http://hallikainen.com/FccRules and comments filed in LPFM proceeding at http://hallikainen.com/lpfm On Thu, 5 Aug 1999 17:30:17 +1000 PJH <elekspam_OUTNETSTRA.COM.AU> writes: {Quote hidden}>PICers, > >I've been looking at the ISD 33000 >voice player chip. It's OK but >needs a 3V supply & 3V regs are >awkward to get ahold of. Anybody >know how critical the 3V limit is? > >The data sheet is a bit obscure but >there is a test cct shown operating >on 3.3V. Just wondering if using 3 >diodes to drop the Vcc would be OK? >It's just that Vcc then becomes a >little uncertain for different >diodes. Would that upset things? > >Thnax - PJH ___________________________________________________________________ Get the Internet just the way you want it. Free software, free e-mail, and free Internet access for a month! Try Juno Web: dl.http://www.juno.com/dynoget/tagj.

now how critical the 3V limit is? > > The data sheet is a bit obscure but > there is a test cct shown operating > on 3.3V. Just wondering if using 3 > diodes to drop the Vcc would be OK? > It's just that Vcc then becomes a > little uncertain for different > diodes. Would that upset things? > > Thnax - PJH I've been using zener diodes to deal with the issue. -- Anniepoo Need loco motors? http://www.idiom.com/~anniepoo/depot/motors.html