BQ25703A: Recommend Power MOSFETs of BQ25703A

Fandy

Part Number: BQ25703A
Other Parts Discussed in Thread: TAS5805M

Hello

Please help recommend power mosfet of BQ25703A to me, thanks ,EVM refference design MOSFETs are have too much margin for my application,

Application: Smart Speaker ,2 pcs 8W Speaker，PA will choice TAS5805M , 2-S 4.2V Li Cell,3000mAh/Cell ,Charger Current less than 2A , adaptor is 5V/2A or 9V/1.5A , system side maybe have total 6A demand

over 6 years ago

0 Jeff F over 6 years ago

TI__Guru**** 166136 points

Fandy,

Q1-Q4 buck/boost power FETs are 12A FETs, Q7 battery FET is a 15A FET and Q5 and Q6 are 8.5A FETs. All seem to be below your desired current levels. Which FET specification does not have enough margin?

0 Paul Yeh over 6 years ago in reply to Jeff F

TI__Genius 16175 points

Hi,

In our EVM board, we can handle at least 65W power rating. So based on your specification, I think our MOSFEt should be no problem.

Thanks

0 Fandy over 6 years ago in reply to Paul Yeh

Expert 2285 points

Hi Paul
Actually I think EVM's MOSFET Voltage and Current Margin is too big ,a bit wasteful for my application, I want to save cost

0 Steve Preissig over 6 years ago in reply to Fandy

TI__Expert 5330 points

Hi Fandy,

I would recommend that you use switching FETs with Qg (Gate charge) ~ EVM value of 6 nC at 4.5V, R_DSON ~ EVM value of 10 mOhm at 4.5V and V_GSTH ~ 1.6 V.

Per your description, you may be able to reduce your requirements of V_DS and I_D. TI has a great parametric search tool at:
www.ti.com/.../products.html

Here is a search with the Qg, R_DSON already plugged in
www.ti.com/.../products.html

You can choose from these the V_DS, I_D and other parameters that meet the margins you feel comfortable with for your application.

Here is the PFET selector tool:
www.ti.com/.../products.html

Regards,
Steve

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BQ25703A: Recommend Power MOSFETs of BQ25703A