74HC4067

The 74HC4067 is a single-pole 16-throw analog switch that doubles as a 16:1 multiplexer or 1:16 demultiplexer. Four address inputs S0 to S3 select one of sixteen bidirectional channels Y0 to Y15 and connect it to the common terminal Z; the enable input E is active low, and when it is high every switch opens regardless of the address. Nexperia builds in break-before-make action, so the common terminal is never momentarily shorted between two channels during an address change — essential when the mux feeds an amplifier or an ADC sample-and-hold. Inputs include clamp diodes, allowing series-resistor interfacing to voltages above VCC.

Supply range is 2.0 V to 10.0 V, and the analog signals may swing the full rail-to-rail window between GND and VCC. On-resistance is the parameter to watch: 80 Ω typical and 160 Ω maximum at VCC = 4.5 V, 70 Ω typical at 6.0 V and 60 Ω typical at 9.0 V, with a peak value (worst point across the signal range) of about 110 Ω at 4.5 V and channel-to-channel mismatch around 8 Ω to 9 Ω typical. Because the on-resistance varies with the instantaneous signal voltage, running the mux at a higher supply improves linearity noticeably. Off-state leakage is ±0.1 µA maximum per channel at 25 °C, supply current is 8 µA maximum at 6 V and 16 µA at 10 V, and the device is specified from −40 °C to +125 °C in SO24, TSSOP24 and DHVQFN24 packages.

Timing is fast for an analog switch: address-to-channel propagation delay is 30 ns typical at 4.5 V and 24 ns at 6 V, channel-to-common delay is 9 ns typical, and turn-on and turn-off times are around 32 ns to 34 ns typical. Delays toward the Z terminal are higher than toward an individual Y because all sixteen switch capacitances are summed at the common node. Power-dissipation capacitance is 29 pF per switch, so account for that if you scan channels quickly into a high-impedance amplifier.

In practice the 74HC4067 is the workhorse of low-cost multi-channel acquisition: sixteen thermistors, battery cells, strain gauges or analog pots feeding a single ADC channel, with a microcontroller driving the address lines. Two design rules keep measurement error down. First, remember that on-resistance forms a divider with the load, so buffer the common terminal with a high-impedance op-amp or allow settling time proportional to Ron × Csample — for an ADC with a 20 pF sample capacitor, a few microseconds after an address change is normal. Second, keep channel wiring short and guarded if you are switching high-impedance sources, because ±0.1 µA leakage across 100 kΩ is already a 10 mV error, and leakage rises to ±8 µA at 125 °C. The part is fully second-sourced: TI's CD74HC4067, onsemi's MC74HC4067A and SG Micro's 74HC4067 are pin and function compatible, with small differences in supply ceiling and on-resistance specification. MOQ is 1 reel for SO24 or 100 pcs cut tape for prototyping, shipping in 1-2 days from Shenzhen stock; authorized channel replenishment runs 4-8 weeks. Counterfeiting is rare on this part number, but confirm the vendor marking and check on-resistance on a sample, since remarked 4051 (8-channel) die occasionally appears in 24-pin lots.