Using TXS102 in a portable device

Oscar Gomez Fuente

Expert 2066 points

Hi everyone,

I've got a problem on a portable device. I've got an IC with and an i2c bus. This device is feed with a Li-Ion battery, so the level voltage is from 2.75V to 4.2V and I have to communicate this IC with a microprocessor feed with 3.3V. So according to the TXS102 datasheet:

VCCB = VBAT

VCCA = 3.3V

When the battery has a voltage from 3.3V to 4.2V there isn't any problem but when the battery is from 3.3V to 2.75V and according to the datasheet of the TXS102 VCCB has to be >= VCCA (3.3V). So I've got a problem.

Does anyone how to solve this problem?

Best regards.

over 9 years ago

0 Clemens Ladisch over 9 years ago

Guru 317480 points

Use VccA for the battery-powered device, and add an LDO so that the voltage is always lower than 3.3 V. (This might create a problem at the lowest battery voltage.)

0 Nirav Patel over 9 years ago

TI__Expert 6335 points

Oscar,

I do not see a solution that does not involve a PCB re-design, in which case you would connect the microprocessor to the VCCB side and the device with the Li-Ion battery to the VCCA side.

Best Regards,
Nirav

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Using TXS102 in a portable device