ADS4225: Amplifier recommendation

Naizeng Wang

Part Number: ADS4225
Other Parts Discussed in Thread: THS4509, , THS4541

Hi team,

Customer wants to use THS4509+ADS4225 to sample up to 2.5V DC voltage. THS4509 is to enlarge the signal and ADS4225 is to translate the analog signal to digital signal. But I think THS4509 is not suitable for this application becuase its min gain is 6dB, and the output voltage of THS4509 may exceed the the input range of ADS4225. Could you please recommend an amplifier? Thanks!

Nison

10 months ago

0 Chase W 10 months ago

TI__Mastermind 18145 points

Hi Nison,

The THS4509 or THS4541 shall be fine. Please suggest to design a pi-attenuator or tee-attenuator (also called t-pad attenuator) to correct the level into a suitable input range for any ADC prior to a matching network when using a fixed gain amplifier that amplifies input beyond ADC limits. THS4541 is adjustable and may be better suited for the customer.

Regards, Chase

0 Naizeng Wang 10 months ago in reply to Chase W

TI__Expert 3735 points

Hi Chase,

Could you please share the design guide of the attenuator? Thanks!

0 Chase W 10 months ago in reply to Naizeng Wang

TI__Mastermind 18145 points

Naizeng,

See below image. This is a 3dB attenuator. To calculate values, you can suggest to use this calculator: https://www.allaboutcircuits.com/tools/t-pad-attenuator-calculator/

Regards

0 Chase W 10 months ago in reply to Chase W

TI__Mastermind 18145 points

This is an example of the 3dB attenuator.

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ADS4225: Amplifier recommendation