NXP HEF4067BP: A Comprehensive Technical Overview of the 16-Channel Analog Multiplexer/Demultiplexer IC
In the realm of electronic system design, the efficient routing of analog signals is a fundamental requirement across a vast array of applications, from data acquisition systems to audio equipment and automated test equipment (ATE). The NXP HEF4067BP stands as a quintessential component addressing this need, serving as a monolithic integrated circuit configured as a single-pole, 16-throw (SP16T) analog switch. This IC functions as both a multiplexer (mux) and a demultiplexer (demux), providing a versatile solution for connecting one common line to one of sixteen separate channels, or vice versa, under digital control.
Fabricated using standard silicon-gate CMOS technology, the HEF4067BP is celebrated for its low power consumption and wide operating voltage range, typically from 3 V to 15 V. This flexibility makes it suitable for interfacing with both modern microcontrollers (e.g., 3.3V or 5V logic) and older higher-voltage systems. A critical feature of any analog switch is its ability to handle signals with minimal distortion and signal loss. The HEF4067BP boasts a low "ON" resistance, typically around 100 Ohms at VDD = 10 V, which remains relatively flat across the entire analog input voltage range. This ensures that the voltage dropped across the switch itself is minimized, preserving signal integrity.
The selection of the desired channel (S0 to S15) is determined by the state of four binary control inputs (A, B, C, D). An additional inhibit (INH) input provides a master control function; when set to a high logic level, it disables all switches, regardless of the state of the address inputs. This is particularly useful for power-saving modes or for preventing signal cross-talk during system initialization.
The architecture of the HEF4067BP includes bidirectional analog switches, meaning the common terminal (Z) and the channel terminals (Y0-Y15) can be used interchangeably. This allows the IC to function identically as a multiplexer (signal from Z to one selected Y) or a demultiplexer (signal from one selected Y to Z). Furthermore, the device can also be used for digital signal routing. A crucial design consideration is the management of digital noise coupling into the analog path. To mitigate this, the IC features separate supply pins for the digital (VDD, VSS) and analog (VEE) sections. The analog supply pin (VEE) can be tied to VSS for single-supply operation or to a negative voltage (e.g., -5V) to handle analog signals that swing below ground, thereby extending the dynamic range of the passable signals.
When integrating the HEF4067BP into a design, several key parameters must be considered. The break-before-make switching action prevents momentary shorting between channels during address changes. The maximum peak-to-peak analog signal voltage that can be switched is equal to the full supply voltage (VDD - VEE). Designers must also be mindful of the settling time, which is the time required for the output signal to stabilize within a certain error band after a channel change, especially critical in high-speed data acquisition systems.
ICGOODFIND: The NXP HEF4067BP is a highly versatile and robust 16-channel analog multiplexer/demultiplexer. Its combination of low ON resistance, wide voltage range handling, and bidirectional capability makes it an indispensable component for designers needing to manage multiple analog signal paths with precise digital control, ensuring both performance and design flexibility.
Keywords: Analog Multiplexer, CMOS IC, Low ON Resistance, Bidirectional Switch, Wide Voltage Range.
