Diana Posted June 5, 2004 Report Share Posted June 5, 2004 Hello,Can anyone help me on my little project herein. I'm using an rail-to-rail operational sub-1V amplifier NCS2001SQ2T1 (ON Semiconductors), for ampifying very low (mono) audio signal from an old reciever. Ampifyer is powered by single 1,4 button cell. Earphones are on output. Since I'm still a beginer in electronics (or complete retard :), I don't know which pin on the NCS2001SQ2T1 should I connect with bat-, bat+, ear1, ear2, input1 and input2 contacts. Because of very small gabarits needed (therefore I use button cell), it is desirable the whole circuit has as minimum aditional components (SMD resistors and capacitors) as possible, regardeles the sound quality.No volume potentiometers also; I need maximum output power that NCS2001 can provide. Simple as that. But not for me !Btw:Could I use 2 or 3 IC-s for aditional amplification ? I would very apriciate a simple scetch if possible. Thx.NCS2001 links:http://www.onsemi.com/site/products/summary/0,4450,NCS2001,00.htmlhttp://www.onsemi.com/pub/Collateral/NCS2001-D.PDF (127KB) Quote Link to comment Share on other sites More sharing options...
audioguru Posted June 5, 2004 Report Share Posted June 5, 2004 Diana,You have selected a voltage amplifier that is not designed to provide power to drive headphones. It is specified with a minimum load of 2000 ohms, and your headphones are probably 32 ohms or less. Even if it was capable of driving headphones, the volume would be very low because your battery voltage is so low. Even if it was capable of driving headphones and you accept low volume, the tiny battery's low capacity would limit operation to only minutes.I suggest that you select an IC and battery that are designed for your application. Quote Link to comment Share on other sites More sharing options...
Diana Posted June 6, 2004 Author Report Share Posted June 6, 2004 Thanks,Can you then suggest an amplifier sutable for my aplication ?It still have to assure small dimensions, 1.4V bat supply, low power consumption, enough power on outut, etc. (looks impossible ?!)... :'( Quote Link to comment Share on other sites More sharing options...
audioguru Posted June 6, 2004 Report Share Posted June 6, 2004 Diana,ON Semi also make small power amplifier ICs for headphones. Although they make one for mono sound, I recommend using the stereo IC since it is the same size and uses the same number of external parts. Besides, you will probably want stereo in the future.You have a choice of 2 ICs, the A version has a fixed gain of 1 and requires very few external parts, and the B version allows you to select gain with 4 external resistors.The NCP2809 can run off a minimum of 2 button cells, with the size of the cells determining duration.The literature for the NCP2809 stereo headphones power amplifier is here:http://www.onsemi.com/site/products/summary/0,4450,NCP2809,00.html Quote Link to comment Share on other sites More sharing options...
wizard Posted June 18, 2004 Report Share Posted June 18, 2004 Diana,According to your needs,you have a large amount of options.I'll suggest one now.Try using,for example,some Philips low-voltage audio amp. ic's(TDA7050T and TDA8559).The ic's that i'm about to suggest,although they aren't SMD,their schematics consist in very few external components(or NO external components whatsoever)The ic's both comply(more or less) with your supply voltage requests(still,i recomend a higher supply voltage,at a higher current maybe - 2 button cells would be better),they both have output fixed gain and they are suited for portable applications.From where i'm looking,they are a good option for your project,and they aren't exphensive either.Anyway,the links to the datasheets are :http://www.semiconductors.philips.com/pip/TDA7050T_N3.htmlhttp://www.semiconductors.philips.com/pip/TDA8559T_N1.htmlST has some low-voltage stereo amps.I've selected two ic's for you:TDA2822D or TS4900 series.Here are links to the datasheets:http://www.st.com/stonline/books/ascii/docs/1463.htmhttp://www.st.com/stonline/books/ascii/docs/8482.htmLoooooong lists of amps and their datasheets(only if you have a considerable ammount of patience ;) )are:For Phillips:http://www.semiconductors.philips.com/catalog/219/283/27117/27130/46145/27133/index.html#27133For STMicroelectronics:http://www.st.com/stonline/books/toc/ds/1268.htmHoping that the info will prove somehow useful,i wish you a sincere GOOD-LUCK with your project. Quote Link to comment Share on other sites More sharing options...
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