If I / O with different signal levels is connected, the driver’s output voltage level may not satisfy the input voltage specifications of receiver, resulting in malfunction or damage to the receiver. It is convenient to use a level shifter to solve such problems.
What kind of abnormality may occur if the voltages between the devices do not match? Here are two examples:
The first is when inputting a signal from a high voltage level to a low voltage level device, as shown in the upper right figure. Devices on the low voltage side often have a low withstand voltage of the input circuit, and if a voltage higher than the withstand voltage is input to it, it may be damaged and destroyed.
The second is when a signal is input from a low voltage level to a high voltage level device as shown in the lower left figure. If a voltage near the input threshold is applied to a device on the high voltage side, the high level signal cannot be recognized, resulting in a malfunction.
A level shifter is required to solve these problems.
Please refer to the FAQ “the application example (5V ⇔3.3V)”.
What options do I have to perform level shifting from 5 V to 3.3 V and vice versa?