TPA2039D1: TPA2039 Gain

sundy xie

Part Number: TPA2039D1
Other Parts Discussed in Thread: TPA2011D1,

Dear,

Our ctm want to use TPA2038. And now they want us to provide the internal resistance value to make sure they can add exact external resistance to keep the Gain at 9.5DB.

Or could you give the external resistance value to get 9.5DB gain? Thanks!

over 6 years ago

0 José Luis over 6 years ago

TI__Mastermind 20085 points

Hi Sundy xie,

The internal resistance value is 150KΩ, so you can calculate the gain with the next formula: G= (2*150KΩ)/Ri. You need an external resistor of 31.5kΩ in order to get 9.5dB. But this device is designed to work with a 12dB fixed gain.
You can have a look the TPA2011D1. This device has the same functionality and pinout as the TPA2039D1. Besides, this device has the function of configurable gain.

Best Regards
José Luis Figueroa
Audio Applications Engineer

0 sundy xie over 6 years ago in reply to José Luis

Intellectual 525 points

Dear Luise,

They used TPA2011D1 in the old product. Now because of cost issue, we recomend TPA2039 to them.

Do you mean the internal resistor of TPA2039 is the same with TPA2011D1?

And we can get 9.5DB gain by using TPA2039 with an external 31.5k resistor,right?

Best regards,

Sundy

0 José Luis over 6 years ago in reply to sundy xie

TI__Mastermind 20085 points

Hi Sundy,

Yes, the internal resistor is the same.
That's right, you need a 31.5KΩ external resistor to get a 9.5dB gain.

Best Regards
José Luis Figueroa
Audio Applications Engineer

0 sundy xie over 6 years ago in reply to José Luis

Intellectual 525 points

Dear Jose,

Could you help to check the unit of this formula?

I think it should be V/V , not DB;

Gain=20log(2Rf/Ri) db

If Rf=150KΩ，Fixed gain=12db; Ri should be 75.38kΩ.

Sundy xie

0 José Luis over 6 years ago in reply to sundy xie

TI__Mastermind 20085 points

Sundy,

You are right. As Rf=150kΩ, so you need to use Ri=100489Ω in order to get a 9.5dB gain.

Best Regards
José Luis Figueroa
Audio Applications Engineer

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TPA2039D1: TPA2039 Gain