TPS22910A: Using load switch to increase CR2032 life

sg_34

Part Number: TPS22910A
Other Parts Discussed in Thread: TPS22860

Hi,

I'm working on a design powered by CR2032 and I'm looking for a solution to increase life of my battery CR2032, and I'm wondering about using TPS22910A :

TPS22910 characteristics :

- active Low (ON input pin)

- RdsON is 61 mOhms

My device is always powered (80% to 90%) and sometimes not powered : is using these TPS22910 a good idea?

Currents are significant :

Device powered : Leakeage current + off supply # 0.2µA for Vin=3V

Device not powered : quiescent current #1.5µA for Vin=3V

Is the solution of using a P-MOSFET alone (FDN304P for example) is not better than the IC in these case?

Thanks for your help or any idea, design or IC to increase design efficiency

Best regards

over 7 years ago

0 Aleksandras_Kaknevicius over 7 years ago

TI__Genius 15710 points

Hi sg_34,

What is the load current for the load switch? This would help give me an idea of how on-resistance and quiescent current factor into this application. If the load current is very small, then you could consider the TPS22860. The on-resistance is larger than the TPS22910A, but the quiescent current is much smaller.

For some general information on discrete MOSFET solutions vs. load switches, please refer to the collateral below.

Video: www.ti.com/.../integrated-load-switches-support-training.page

App Note: www.ti.com/.../slva716

Blog: e2e.ti.com/.../when-to-use-load-switches-in-place-of-discrete-mosfets

Thanks,

Alek Kaknevicius

0 sg_34 over 7 years ago in reply to Aleksandras_Kaknevicius

Intellectual 500 points

Hi,

Load current is very small, few µA, less than 10, with spike because Bluetooth is enabled and will advertize each 5 to 10 seconds (configureable).

TPS22860 is interesting, but Rdson is high compare discrete MOSFET : ten times higher around 1 Ohm @ 3V : not problematic?

In my case Vin=Vbias voltage from CR2032

About input used to switch ON, my idea is to use an ouput from a magnetic sensor (push pull) able to drive 1mA (SM353LT), in this case no need to add a resistor

Is there an equivalent to TPS22860 where ON pin is active Low?

Best regards

0 Aleksandras_Kaknevicius over 7 years ago in reply to sg_34

TI__Genius 15710 points

Hi sg_34,

I don't think the on-resistance of 1 ohm will be a problem with a load under 10uA. Assuming a max load current of 10uA, a 1 ohm switch will cause a voltage drop of 0.01mV. On a 4.2V rail, that would be a voltage tolerance of 99.99%.

Also, we do not have an active low version of the TPS22860.

Thanks,

Alek Kaknevicius

0 sg_34 over 7 years ago in reply to Aleksandras_Kaknevicius

Intellectual 500 points

Do you have an idea, solution, IC's , ultra low power, to be used to achieve a solution "Active Low" ? SN74xxx?

Best regards

0 Aleksandras_Kaknevicius over 7 years ago in reply to sg_34

TI__Genius 15710 points

Hi sg_34,

At the moment we do not have any devices released other than those mentioned in this thread. However, it would be helpful to know some additional application / end equipment details to help us define future devices.

Could you please send me an email at a-kaknevicius@ti.com so that we can discuss?

Thanks,

Alek Kaknevicius

0 sg_34 over 7 years ago in reply to Aleksandras_Kaknevicius

Intellectual 500 points

Hi Alek,

Have you received my email at the specified adress?

Best regards

Stephane

0 Aleksandras_Kaknevicius over 7 years ago in reply to sg_34

TI__Genius 15710 points

Hi Stephanie,

I received the email you sent and have responded.

Thanks,

Alek Kaknevicius

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TPS22910A: Using load switch to increase CR2032 life