ADC3441: How to understand "Each input pin (INP, INM) must swing symmetrically between (VCM + 0.5 V) and (VCM – 0.5 V)" in datasheet of ADC3444

Liyang Du

Part Number: ADC3441
Other Parts Discussed in Thread: ADC3444, ADC3444EVM, LMH5401

I want to use ADC3444 to digitalize a wide bandwidth analog signal with single polarity from -0.2V~1V. As described in datasheet that "Each input pin (INP, INM) must swing symmetrically between (VCM + 0.5 V) and (VCM – 0.5 V)", so it means that I cannot input this signal single-ended, because signal does not swing symmetrically? Even though the common mode voltage range requirement can be met but the signal still can not input as single end due to nonsymmetric? I am confused with this expression in datasheet. Thanks!

over 3 years ago

0 Amy over 3 years ago

TI__Genius 15321 points

Hi Liyang,

A balun is commonly used to convert a single ended input to differential. Did you purchase the TI ADC3444EVM? If so, then there is already a balun on the board.

Here is the link to find the EVM schematic (download the "ADC34xxEVM Design Package" under “Design Files”): https://www.ti.com/tool/ADC3444EVM

Here you can see the balun that was used in the design.

Regards, Amy

0 Liyang Du over 3 years ago

Prodigy 160 points

Hi Amy,

Thank you very much! I know there is a balun on the EVM and I have tested it. Considering my application I will apply a single end to differential amplifier in my design. Thanks!

Best Regards,

Liyang

0 Rob Reeder over 3 years ago in reply to Liyang Du

TI__Mastermind 31590 points

Hi Liyang,

The LMH5401 would be a good recommendation for a SE to DIFF interface.

Regards,

Rob

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ADC3441: How to understand "Each input pin (INP, INM) must swing symmetrically between (VCM + 0.5 V) and (VCM – 0.5 V)" in datasheet of ADC3444