TS3A227E: TS3A227E TIP maximum voltage

SYLVAIN BOURIOT

Part Number: TS3A227E

Hello,

I will use on new electronic board (see attached schematic).
The headphones will be driven by a single ended audio amplifier (the output voltage will be in range 0-5V).
C1, C2 are DC blocking capacitors, they are used to suppress offset voltage, so the TIP signal will be in range -2.5V/+2.5V.
But, when C2 ( or C1) is not charged, it's acts as a short circuit, and if the output voltage of the amplifier is at 5V, the signal "TIP" will be also at 5V.
The datasheet specifies a maximum level on TIP signal of VDD+0.5V = 3.3+0.5 = 3.8V.So the TIP signal will therefore be out of specification during few ms.
May it be a problem?
Do you have a proposal to avoid this?

Thanks.

Best Regards.

Sylvain

over 4 years ago

0 Ambroise Suter over 4 years ago

TI__Expert 3820 points

Hi Sylvain,

The 5V on TIP can damage the ESD protection and possibly the circuitry as well.
Have you tested this setup with an EVM?

Is there a way to use 3.3 V on both devices? This would highly simplify the design.

You can find a design suggestion in our BOOSTXL-AUDIO (page 16).

Thank you and best regards,

Ambroise

0 SYLVAIN BOURIOT over 4 years ago in reply to Ambroise Suter

Intellectual 360 points

HI Ambroise,

Thanks for your reply.

No, I haven't tested this setup with EVM. But Even It's works with one EVM, no conclusion can be made!!! we are out of specification!
It's impossible to use 3.3V on both devices, because we use an existing board with an audio amplifier powered by 5V.

Best Regards.

Sylvain

0 Ambroise Suter over 4 years ago in reply to SYLVAIN BOURIOT

TI__Expert 3820 points

Hi Sylvain,

that is correct, failures could occur at any time in this setup.

Either you have to supply the audio switch with 4.5 V, Vtip could then go up to 5V, or you have to protect this pin from the 5V with a Zener diode or other voltage clamping methods. In turn this could add small leakage currents into the audio circuits.

In addition to the Zener you could try to add a resistor in series with the Zener to have less sharp voltage drops.

Let us know if you have other questions.

Best regards,

Ambroise

0 SYLVAIN BOURIOT over 4 years ago in reply to Ambroise Suter

Intellectual 360 points

Hi Ambroise.

Thank you !

Best Regards.

Sylvain

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TS3A227E: TS3A227E TIP maximum voltage