TI PCM4222 Evaluation Board Power Supplies

[billadair]

Hello All,

I've just purchased a TI PCM4222 and am exploring ways to power it. I have a decent quality lab power supply but would prefer not to use it. (It is 240v, I am in the US and I don't want to use the 110-240 step up transformer I have for this purpose.)

I've explored standard +/-15v powers supplies from digikey etc. but they are all come with excessive 150mV ripple. I would prefer to use battery and a switchable charging circuit. i.e. when the ADC is in use the charger is not.

So what voltage battery (batteries?) will do the job? The spec sheet has voltage extremes of 6v-16v for the +15v.

I see ghg has been testing his unit using SLA. The only SLA batteries reasonably cheap are 12v. I can obtain 14.4 volt nimh battery packs and their chargers easily but will this power the op amps properly?

TIA
Bill

[recorder]

Hi Bill,

I can't really help you, unfortunately, but I'd be also highly interested in such a solution. I am in Europe though... Could you please point me towards the ghg thread?

[5th element]

12 volts SLA batteries will do fine. There's a reason why they specify such a large voltage range for the analogue supplies.

The opamps on the eval board can probably work down as low as +-2.5v. Trouble is with this you cannot get the +5 and +3.3 volt lines required for the ADC, so a minimum of +6 is given to account for any drop out in the +5 and +3.3 regulators.

Opamps usually sound and perform better when driven by a higher voltage, but this doesn't mean to their maximum value either though. They simply perform better when the rails sit a decent amount above the maximum signal level they will ever get to see.

+-12v from SLAs is more then enough.

[billadair]

Recorder,
The thread DIY Analog-to-Digital Converter project.Audio measurements tool
has a discussion of a DIY A2D and comparisons with the TI board (but little in the way of power information other than a reference to SLA).
Bill