PGA2311: PGA2311

Hello Lennert,

The PGA2311 datasheet is specific about the +/-5 V analog supplies and +5 V digital supply.

One way, an possibly the easiest way to meet these supply requirements and when only a  single + 5 V supply is available, is to follow the+5 V supply with a switched capacitor voltage converter. A switched capacitor voltage converter is a dc charge pump device that produces the negative of the voltage applied to its input. Thus, one can produce the -5 V that the PGA2311 requires from the +5 V supply. The switched capacitor voltage converter does not require an external inductor that some other dc-to-dc converters may require to produce this function. Do keep in mind that any dc-to-dc converter solution will have some output noise and some additional filtering may be needed for lowest PGA2311 noise performance.

The PGA2311 is supported by our Precision Amplifiers group, but we don't cover dc-to-dc converters. However, using the TI homepage and searching on Power Management products these two TI switched capacitor voltage converters LM2662 and LM828 were produced:

Attempting to use a single +10 V would prove a difficult pursuit. If used, think off it as every PGA2311 pin function requiring a +5 volt shift in their voltage levels. Most apparent VA- and VD- would move -5 V up to 0 V. The analog inputs would be referenced to VAGND at a level of +5 V, instead of 0V. A similar condition for the analog outputs. All of the digital pin low/high levels would be increased by +5 V. Finally, VA+ and VD+ would be connected to +10 V. If input and output sources are ground referenced at 0 V, level shifting by +5 V, or possibly ac coupling would be required. There may be unforeseen consequences powering the PGA2311 in that manner and TI can provide no assurances about its performances. 

Regards, Thomas

Precision Amplifiers Applications Engineering