Other micro-controller uses 5v as standard input voltage, many latest device modules, popular sensors, GPS, RF modules, Flash Memories, SPI storage, Display, use 3 to 3.3v most of this devices requires logic level conversion to protect them from high voltage signals. This devices are mostly running on Level Shifting required for i2C communication protocol most popular for this required is using FET AN10441 designed by NXP this device works with high voltage upt to 10v to 1.8v down. Logic Level shifting may require when interfacing legacy devices that use geometry process. For bidirectional bus system like i2C. a level shifter must also be bidirectional, without the need of a direction control signal. The solution to solve this issue is by connection a discrete MOSFET to each bus line. Another solution is using 2N7000 N-Channel MOSFET and pull-up with 2.2k resistors.
2N7000, 2N7002, NDS7002A is a N-Channel enhancement mode field effect transistors with a high cell density, These electronic device have been design to minimize on-state resistance while providing rugged, reliable and fast switching performance, can be used in most application requiring up to 400 mA DC and can deliver pulse currents up to 2 A. The 2N7 and NDS7 are suited for low-voltage, low-current application such as small servo, motor control, power MOSFET, gate drivers and switching applications. for more details see below the datasheet and the diagram below.
- 2N7000 or AN10441
- 2.2k Resistor
- 3mm Led (Optional )
- 220k Resistor for LED (Power Indicator)