MXL7704 (Raspberry Pi)

This page is under construction and may be incomplete.

The MXL7704 is a programmable quadruple step-down DC/DC converter that is used in the following Raspberry Pi models:


 * Raspberry Pi 3 (A+ and B+) (MXL7704-R3 version)
 * Raspberry Pi 4 (all) (MXL7704-P4 version)

Cause of failure
If the Pi's 5V pin is shorted to the neighboring 3.3V pin, the MXL7704 will try to clamp the voltage on the 3.3V line. This destroys the MXL7704 chip, leaving the 3.3V line permanently shorted to GND.

Changing the chip

 * Add a bit of solder to the side of the chip on pins 10, 17 and 18 before soldering it in. It can be difficult to get solder to stick there once the chip is connected to the PCB's ground pad.

Configuring
The MXL7704 chip can be configured via an I2C interface. The I2C address depends on the version of the chip:

Every version of the chip can be installed in every Raspberry Pi model, but its configuration will need to be changed manually if a version different than the original one is used.

Known configurations are listed below:

The following contacts can be used to acces the I2C interface:

Note that the I2C interface usually doesn't work if the chip is broken.