OPA1637: Design a balanced audio signal receiver circuit for ADC(AKM AK5554) by using OPA1637

Younggi Jung

Part Number: OPA1637
Other Parts Discussed in Thread: TINA-TI

Hello.

Several month ago, I was recommended a FDA from Iwata Etsuji

I need a circuit for balanced audio signal receiver circuit.

Could you please design a circuit 8V peak to peak(+3.5v, -3.5v) -> 0.2 to 4.8v balanced audio signal?(2.5v mid) and frequency range 20Hz to 20kHz by using OPA1637?

This signal goes to AKM AK5554 ADC IC.

tina TI file would be better.

Thank you.

over 4 years ago

0 Iwata Etsuji over 4 years ago

TI__Expert 6400 points

Hi Jung,

Thank you for your interests to OPA1637.

I will prepare the analog front end circuit for AK5554 with respect to the information on its datasheet.

Best regards,
Iwata Etsuji

0 Iwata Etsuji over 4 years ago

TI__Expert 6400 points

Hi Jung,

I'm sorry for delayed update.

I have prepared the TINA-TI simulation for OPA1637 as the AK5554 front end.

OPA1637Bessel-LPF+AK5554.TSC

Please review the attached file and please let me know if you need further optimization.

Best regards,
Iwata Etsuji

0 Younggi Jung over 4 years ago in reply to Iwata Etsuji

Prodigy 100 points

Hi Iwata Etsuji.

Thank you for nice work for me.

Actually, Input analog signal is banaced 8Vpp thus I modified gain and input.

Could you please final check for me?One more question, is it necessary serial capacitor to eliminate DC offset in input line??

Some of schematic serial capacitor is attached at input signal line to eliminate DC offset. but your simulation is not appeared.

Is it really necessary? what is the cost for that? Thank you!

OPA1637Bessel-LPF+AK5554_revINPUT_BALANCED_v1.TSC

0 Iwata Etsuji over 4 years ago in reply to Younggi Jung

TI__Expert 6400 points

Hi Jung,

I have modified the simulation with respect to the 8Vpp differential input and required 5.6Vpp differential input voltage range of AK5554.

OPA1637Bessel-LPF+AK5554_Diff8Vpp.TSC

Regarding the input DC blocking caps, it depends on the system requirement.
If the customer must consider the risk of input DC offset from the signal source to OPA1637, at least 10uF(hopefully film cap) could be recommendable, considering with low audible frequency response.

Thank you and Best regards,
Iwata Etsuji

0 Younggi Jung over 4 years ago in reply to Iwata Etsuji

Prodigy 100 points

It is really helpful! Thank you Iwata Etsuji!

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OPA1637: Design a balanced audio signal receiver circuit for ADC(AKM AK5554) by using OPA1637