The CD74HC4067 High-Speed CMOS 16-Channel Analog/Digital Multiplexer Breakout Module designed specifically for 74HC4067. 74HC4067 is a 16-Channel Analog/Digital Multiplexer/Demultiplexer that can route both analog and digital signals in both directions. The CD74HC4067 internal switches are bidirectional, support voltages between ground and VCC. It offers low “on” resistance and low “off” leakage. In order to prevent crosstalk, “break-before-make” switching performed.
This chip functions like a rotary switch mean that it internally routes the common pin (COM in the schematic, SIG on the board) to one of 16 channel pins (CHANxx). The “enable” pin, in the breakout board will completely disconnect the common pin (all switches “off”) when driven high. The 74HC4067 operates at a voltage range of 2V to 6V, so it is compatible with both 3.3 and 5V logic.
The 4 digital outputs connected to the chip’s address select pins (S0-S3) and send it the binary address of the channel as per the user need. When a channel is ON, it provides resistance of about 70 ohms which allows signals to flow both ways. Using a 5V power supply, we measured about 60 ohms. The maximum current is 25mA through any of the channels. This board is capable of connecting 16 sensors to your system using only 5 pins. Moreover, an enable pin (EN) that is active LOW and defaults to that value. Under the LOW state, the device enables the channel selected by the address lines. Whereas when EN pulled HIGH, all channels are disabled.
Since the mux/demux also works with digital signals; used to pipe TTL-level serial data to or from multiple devices. For example, it can be used to connect the TX pins of 16 devices to one RX pin on your microcontroller. And can select any one of those 16 devices. If you want two-way communications; you can add a second board to route your microcontroller’s TX line to 16 device’s RX lines. By using multiple boards, you can create similar arrangements for I2C, SPI, etc.