BQ25125: Looking for a better part ?

James Sullivan73

Prodigy 195 points

Part Number: BQ25125

Hello,

I am using the BQ25125 to power a radio from a single cell at 3.3 volts.

Sadly, when I increase the output voltage from the 1.8 volts to 3.3 volts - the I2C quits working because

the thresholds are determined from Vsys - (not clear in the datasheet).

In my all 1.8 volt design - this will require me to add a level shifter.

Is there another part that has the DC-DC and I2C that will work without a level shifter ?

over 1 year ago

0 Juan Ospina over 1 year ago

TI__Mastermind 18435 points

Hi James,

I'm confused with regards to the I2C no longer functioning when VSYS is set to 3.3V. The charger should be able to communicate via I2C if SYS is set to 3.3V, are your I2C lines pulled up to the VSYS rail? Or is this a limitation from the side of your application?

Best Regards,

Juan Ospina

0 James Sullivan73 over 1 year ago in reply to Juan Ospina

Prodigy 195 points

Hi Juan,

I need my I2C to be pulled up to 1.8 volts, while Vsys is set to 3.3 volts.

Many I2C parts would work under this condition - but not the BQ25125.

0 Juan Ospina over 1 year ago in reply to James Sullivan73

TI__Mastermind 18435 points

Hi James,

I think your best bet would be the BQ2515x family of devices. The BQ25155 has an integrated LDO rail which can provide up to 3.7V and 150 mA. This charger includes a VIO pin which can be connected to your digital rail to set the digital signal voltages.

Best Regards,

Juan Ospina

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BQ25125: Looking for a better part ?