LP8758A1E0

Hi Markus,

  Since the device output sampling through FB pin is not implemented by resister divider; it's by active current source; its output voltage can be increased slightly, but its performance becomes worse; so, it's not recommended to change its output voltage by external resister divider.

 If your application uses it for peripheral power supply and it has an I2C master power-on first, then follow steps can get expected voltage:

1.            Power on I2C master first;

2.            Keep LP8758-E0 EN1 pin low during I2C master power-on;

3.            Rising up the NRST pin for I2C communication (The NRST pin can be connected to the Vin through a RC for power-up reset);

4.            I2C master sets all rails output voltage through BUCKX_VOUT to get their expected voltage; (X=0,1,2,3 related for Buck0, 1,2,3)

5.            Rising up the EN1 pin, then all outputs will be working for customer’s expected voltage.

  Thanks!

  Phil

Hi Phil,

thanks for your clarification. I can not use your procedure because the regulators should supply an IMX6 which is also the I2C master with 1.35V and 3.3V.

best regards

Markus