Opamp on battery

Hello,
I am building a dac that is battery based until now. Now i am at the iv stage and would like to use the lme49990 opams, because i like their neutral sound.
Now my question : the lme49990 needs a positive and negative voltage, but i only have positive voltages on battery. Is there a way to generate a nehative voltage out of a battery or will i need to skip the lme49990 and choose a single voltage opamp ? Is there any single voltage opamp comparable to the lme49990 ?

Thanks
Tom
 

Monte McGuire

Member
Paid Member
2013-07-28 2:58 am
Use two batteries? Also keep in mind the high idle current of the LME49990 - it's around 10mA each at high voltages. This is probably one of the reasons why it performs so well, but still, for a battery supply, keep this high idle current in mind. And, don't starve it for voltage. It works very well at ±17V supplies. (Note - this is the same thing as a 34V single supply as long as you get the inputs to be within the permissible input common mode voltage range.)

Or, one could simply design an effective power supply...?
 
Rhanks for the help. The rail splitter is an option. Does it introduce much noise to the negative rail ?
The 10mA at idle are no problem. I use two 8ah lifepo4 batteries for 6,4v. Does the lme49990 behave much better at higher voltages ? I can give it +/-6V and not more at the moment. I read somewhere that it runs fine from 5V upwards. Is that right ?
 

Monte McGuire

Member
Paid Member
2013-07-28 2:58 am
The data sheet specifies the LME49990 at ±5V, and the distortion plots look very close to those for ±15V, except for the output voltage swing of course. The output swing will be somewhat reduced, since it's not a rail-to-rail amplifier, but there is no rail-to-rail amp that can give you the same level of performance. So, a pair of 6.4V batteries should work well, and you avoid the hassles of a rail splitter or other AC coupling / biasing schemes.