A good PCB layout for the VN800S involves keeping the power supply lines (VCC and GND) as short as possible, using a solid ground plane, and placing decoupling capacitors close to the device. A 4-layer PCB with a dedicated power plane and a solid ground plane is recommended.
To ensure reliable communication, use a dedicated SPI bus with a maximum length of 30 cm, and add a 100-ohm series resistor to the SCK line to reduce ringing. Also, ensure that the microcontroller's SPI clock frequency is within the VN800S's specified range (up to 10 MHz).
The recommended power-up sequence is to apply VCC first, followed by the input voltage (VIN) and then the enable signal (EN). This ensures that the internal voltage regulators are properly initialized.
The VN800S has a built-in overcurrent protection feature that limits the output current to 1.5 A. If an overcurrent condition is detected, the device will automatically shut down. To handle this, implement a retry mechanism in your firmware to reset the device and retry the operation after a short delay.
The maximum allowed voltage on the input pins (VIN, SCK, MOSI, MISO, and CS) is 6 V. Exceeding this voltage may damage the device.
VN800S datasheet
by STMicroelectronics
