ADS8506: VANA Cap

Takashi Onawa

Genius 13200 points

Part Number: ADS8506
Other Parts Discussed in Thread: ADS8681

Hi Team,

Two quick questions,

1. Can we use 10uF ceramic cap instead of 10-µF tantalum as Vana buld cap?

2. Could you tell me the background the reason why 10uF is needed for Vana pin?

Regards,

Takashi Onawa

over 3 years ago

0 Dale Li over 3 years ago

TI__Mastermind 35550 points

Hi Takashi,

1. I did not see any risk to use a ceramic cap for the power supply, ceramic caps are frequently used on our EVM boards.

2. The analog power supply is very important for data conversion because it can directly affect your measured performance, this is more obvious for the ADC devices which do not have a higher PSRR, the PSRR rejection on ADS8506 is only around -75dB since this is an old device. The combination of 0.1uF cap and 10uF cap can effectively suppress both high and low frequency interference signals on the power supply. However, only one 0.1uF cap can be used as a decoupling cap if you have a very clean analog power source in your system.

ADS8681 ADC family is the new generation single channel ADC family which can support a direct bipolar input signal with more range options on a single 5V power supply, it has integrated analog front-end(AFE) including PGA also has a better performance.

12-Bit: ADS8661(1.25Msps) and ADS8665(500ksps)

16-Bit: ADS8681(1Msps), ADS8585(500ksps)

Thanks&regards,

Dale