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Dual Power Supply Help

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GooseElectro

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I am trying to make a volume control circuit using a PGA2311 digital voulme IC. However it need a +5v digital power supply and a +/- 5 v analouge power supply. What is the best way to make a dual power supply for the +/-5v? Any suggestions are much appreciated. Thank You
 
How about something like this? See link.
**broken link removed**
 
for lower currents

for the +5V
60-mA, 5.0-V, Buck/Boost Charge Pump in ThinSOT-23
Inductorless DC/DC Regulators (Charge Pumps) - Buck-Boost Charge Pump Regulators - REG71050 - TI.com

for the -5V
60mA Charge Pump Voltage Inverter with Fixed 50kHz Operation
https://www.electro-tech-online.com/custompdfs/2010/05/tps60402.pdf


for higher currents using a single ic, this could work.
Create a Split-Rail Power Supply with a Wide Input Voltage Buck Regulator
https://focus.ti.com/general/docs/litabsmultiplefilelist.tsp?literatureNumber=slva369
 
If you have a spare I/O pin on the micro that you can set to toggle, then you can build a charge pump for the (-) supply.
 
Set an unused pin on the micro to Output. Attach the following circuit. Alternate between 1 and 0 at frequent intervals. If you have a timer pin available this is easier.
 

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Another point for the pga2311: http://www.datasheetcatalog.org/datasheet/texasinstruments/pga2311.pdf
could I use the
same +5v for bothe analouge and digital supply?
You could, but you may get digital noise into the analog signal. Note Figure 6 in the data sheet showing separation of the analog and digital as much as possible.

You would have to do very good decoupling between the analog and digital sides of the 5V such as a small resistor or ferrite filter bead in series with the power and a small ceramic and larger electrolytic cap in parallel to analog ground at the PGA2311 chip.
 
You could, but you may get digital noise into the analog signal. Note Figure 6 in the data sheet showing separation of the analog and digital as much as possible.

You would have to do very good decoupling between the analog and digital sides of the 5V such as a small resistor or ferrite filter bead in series with the power and a small ceramic and larger electrolytic cap in parallel to analog ground at the PGA2311 chip.

Thank you very much for your reply,

Would it be a better idea to use two different +5v regulators? Will this save having to do decoupling or will i still have the same problem?

Thanks again
 
Two different regulators will minimize the decoupling requirements. You still need the normal decoupling capacitor on the IC power pins.
 
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