Hardware (designing PCB schematics and layout)

AN4450

8/26

DocID025978 Rev 1

2.1.3

Typical application circuit

Figure 5. LPS25H electrical connection (I²C communication example w/SA0=1)

Key notes:

The device core is supplied through the VDD line. Power supply decoupling capacitors

(100 nF and at least 4.7 µF) must be placed as near as possible to the supply pads of the

device.

VDD_IO should match the one requested by the host controller. In any case VDD_IO must

be the same or lower than VDD. In the example shown here, VDD_IO is connected to VDD.

Please note that the LPS25H does not have an internal pull-up on the I²C lines (SCL and

SDA). They must be added externally according to the I²C bus speed and load, and

connected to VDD_IO.

In I²C mode, SA0 =1 (pin directly connected to VDD_IO) sets the slave address to 0xBA for

write and 0xBB for read. A pull-up resistor could be a better choice if there is a need to

communicate alternatively in I²C or SPI 4-wires, since pin 5 is SDO for SPI 4-wires and of

course it cannot function if hard-connected to VDD_IO.

The I²C interface is compliant with fast mode (400 kHz) I²C standards as well as with normal

mode.