hello, what device (buffer) can you guys suggest to interface inputs to the tms320f2812 ezdsp board? i'm planning to use 74LS125. I'm a little unsure because the current it gives off is 20uA. And according to the datasheet of tms320f2812, the current should only be 2uA. thanks
buffer for tms320f2812
Started by ●June 23, 2008
Reply by ●June 24, 20082008-06-24
On Jun 23, 6:26 am, "kathlyn_uy" <kcharma...@gmail.com> wrote:> hello, > > what device (buffer) can you guys suggest to interface inputs to the > tms320f2812 ezdsp board? > > i'm planning to use 74LS125. I'm a little unsure because the current it > gives off is 20uA. And according to the datasheet of tms320f2812, the > current should only be 2uA. > > thanksI'm not familiar with your board, but a current source will not deliver more current to a load than the resistance/impedance of the load will allow (remember Ohm's law). Don't worry about the mismatch between your source and load, as long as the source can meet the minimum current requirement of the load. Darol Klawetter
Reply by ●June 24, 20082008-06-24
kathlyn_uy wrote:> hello, > > what device (buffer) can you guys suggest to interface inputs to the > tms320f2812 ezdsp board? > > i'm planning to use 74LS125. I'm a little unsure because the current it > gives off is 20uA. And according to the datasheet of tms320f2812, the > current should only be 2uA.You are idiot. The 74LS125 is 5V part, whereas TMS320F2812 is a 3.3V part. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
Reply by ●June 24, 20082008-06-24
Darol Klawetter wrote:> On Jun 23, 6:26 am, "kathlyn_uy" <kcharma...@gmail.com> wrote: >> hello, >> >> what device (buffer) can you guys suggest to interface inputs to the >> tms320f2812 ezdsp board? >> >> i'm planning to use 74LS125. I'm a little unsure because the current it >> gives off is 20uA. And according to the datasheet of tms320f2812, the >> current should only be 2uA. >> >> thanks > > I'm not familiar with your board, but a current source will not > deliver more current to a load than the resistance/impedance of the > load will allow (remember Ohm's law). Don't worry about the mismatch > between your source and load, as long as the source can meet the > minimum current requirement of the load.A colleague -- a physicist, not an engineer -- once borrowed one of my adjustable-voltage power supplies that also had an adjustable current limit. He returned with it shortly after, annoyed that it seemed to be inoperative. It turned out that he wanted to adjust current and voltage independently without altering the load. At first, he was adamant that Ohm had nothing to do with it. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●June 24, 20082008-06-24
On Jun 24, 10:24 am, Vladimir Vassilevsky <antispam_bo...@hotmail.com> wrote:> kathlyn_uy wrote: > > hello, > > > what device (buffer) can you guys suggest to interface inputs to the > > tms320f2812 ezdsp board? > > > i'm planning to use 74LS125. I'm a little unsure because the current it > > gives off is 20uA. And according to the datasheet of tms320f2812, the > > current should only be 2uA. > > You are idiot. > > The 74LS125 is 5V part, whereas TMS320F2812 is a 3.3V part. > > Vladimir Vassilevsky > DSP and Mixed Signal Design Consultanthttp://www.abvolt.comSome 3.3V parts have 5V tolerant inputs. Could it be that the OP's board has a 5 V tolerant buffer or that the TMS320F2812 has some 5 V tolerant inputs?
Reply by ●June 24, 20082008-06-24
On Jun 24, 11:07 am, Jerry Avins <j...@ieee.org> wrote:> Darol Klawetter wrote: > > On Jun 23, 6:26 am, "kathlyn_uy" <kcharma...@gmail.com> wrote: > >> hello, > > >> what device (buffer) can you guys suggest to interface inputs to the > >> tms320f2812 ezdsp board? > > >> i'm planning to use 74LS125. I'm a little unsure because the current it > >> gives off is 20uA. And according to the datasheet of tms320f2812, the > >> current should only be 2uA. > > >> thanks > > > I'm not familiar with your board, but a current source will not > > deliver more current to a load than the resistance/impedance of the > > load will allow (remember Ohm's law). Don't worry about the mismatch > > between your source and load, as long as the source can meet the > > minimum current requirement of the load. > > A colleague -- a physicist, not an engineer -- once borrowed one of my > adjustable-voltage power supplies that also had an adjustable current > limit. He returned with it shortly after, annoyed that it seemed to be > inoperative. It turned out that he wanted to adjust current and voltage > independently without altering the load. At first, he was adamant that > Ohm had nothing to do with it. > > Jerry > -- > Engineering is the art of making what you want from things you can get. > �����������������������������������������������������������������������:)
Reply by ●June 24, 20082008-06-24
On Jun 24, 11:24�am, Vladimir Vassilevsky <antispam_bo...@hotmail.com> wrote:> kathlyn_uy wrote: > > hello, > > > what device (buffer) can you guys suggest to interface inputs to the > > tms320f2812 ezdsp board? > > > i'm planning to use 74LS125. I'm a little unsure because the current it > > gives off is 20uA. And according to the datasheet of tms320f2812, the > > current should only be 2uA. > > You are idiot. > > The 74LS125 is 5V part, whereas TMS320F2812 is a 3.3V part. > > Vladimir Vassilevsky > DSP and Mixed Signal Design Consultanthttp://www.abvolt.comTha is right, you are an idiot. Now go quit your job, refund all your back wages and jump off a bridge! And never do anything stupid again! - especially here.
Reply by ●June 24, 20082008-06-24
Fie, what a shame. Old timer looses his face in public. Welcome to the plonk file. VLV bulegoge@columbus.rr.com wrote:> On Jun 24, 11:24 am, Vladimir Vassilevsky <antispam_bo...@hotmail.com> > wrote: > >>kathlyn_uy wrote: >> >>>hello, >> >>>what device (buffer) can you guys suggest to interface inputs to the >>>tms320f2812 ezdsp board? >> >>>i'm planning to use 74LS125. I'm a little unsure because the current it >>>gives off is 20uA. And according to the datasheet of tms320f2812, the >>>current should only be 2uA. >> >>You are idiot. >> >>The 74LS125 is 5V part, whereas TMS320F2812 is a 3.3V part. >> >>Vladimir Vassilevsky >>DSP and Mixed Signal Design Consultanthttp://www.abvolt.com > > > Tha is right, you are an idiot. > > Now go quit your job, refund all your back wages and jump off a > bridge! > > And never do anything stupid again! - especially here.
Reply by ●June 26, 20082008-06-26
>you can actually power the 74ls125 with a lower supply voltage..around4.43V gives u a fixed 3V output.. :)> >kathlyn_uy wrote: > >> hello, >> >> what device (buffer) can you guys suggest to interface inputs to the >> tms320f2812 ezdsp board? >> >> i'm planning to use 74LS125. I'm a little unsure because the currentit>> gives off is 20uA. And according to the datasheet of tms320f2812, the >> current should only be 2uA. > >You are idiot. > >The 74LS125 is 5V part, whereas TMS320F2812 is a 3.3V part. > > > >Vladimir Vassilevsky >DSP and Mixed Signal Design Consultant >http://www.abvolt.com > >
Reply by ●June 26, 20082008-06-26
thank you very much for clearing that up with me :)>On Jun 23, 6:26 am, "kathlyn_uy" <kcharma...@gmail.com> wrote: >> hello, >> >> what device (buffer) can you guys suggest to interface inputs to the >> tms320f2812 ezdsp board? >> >> i'm planning to use 74LS125. I'm a little unsure because the currentit>> gives off is 20uA. And according to the datasheet of tms320f2812, the >> current should only be 2uA. >> >> thanks > >I'm not familiar with your board, but a current source will not >deliver more current to a load than the resistance/impedance of the >load will allow (remember Ohm's law). Don't worry about the mismatch >between your source and load, as long as the source can meet the >minimum current requirement of the load. > >Darol Klawetter >
