CMOS single 8-channel analog multiplexer / demultiplexer with logic-level conversion, in a SOIC-16 package. A 3-bit binary address (A, B, C) connects one of eight channels (CH0-CH7) to the common COM pin bidirectionally, so it works as a mux or a demux. An active-high INH inhibit floats all channels, and a separate VEE lets it pass bipolar analog signals below ground. VDD spans 3-18 V. The classic way to read many analog inputs on one MCU ADC pin.

Pinout

Pin	Name	Type	Function
1	CH4	bidirectional	Channel 4 analog in/out. Bidirectional analog switch terminal; connects to COM when address = 100 and INH = 0.
2	CH6	bidirectional	Channel 6 analog in/out. Bidirectional analog switch terminal; connects to COM when address = 110 and INH = 0.
3	COM	bidirectional	Common out/in. Shared analog terminal that is switched to the addressed channel (CH0-CH7). Signal may swing from VEE to VDD.
4	CH7	bidirectional	Channel 7 analog in/out. Bidirectional analog switch terminal; connects to COM when address = 111 and INH = 0.
5	CH5	bidirectional	Channel 5 analog in/out. Bidirectional analog switch terminal; connects to COM when address = 101 and INH = 0.
6	INH	input	Inhibit (active-high). When INH = 1 (VDD), all channels are OFF (disconnected from COM). When INH = 0 (VSS), the channel selected by A/B/C is connected to COM.
7	VEE	power_in	Negative analog supply. Sets the lower end of the analog signal range; may be tied to VSS for single-supply operation or to a negative rail (e.g. −5V) for dual-supply. VDD − VEE ≤ 20V.
8	VSS	power_in	Digital/logic ground reference. Logic 0 level for INH and address inputs A/B/C.
9	C	input	Channel select address bit C (MSB). Digital input; logic levels 0 = VSS, 1 = VDD. Selects one of eight channels together with A and B.
10	B	input	Channel select address bit B. Digital input; logic levels 0 = VSS, 1 = VDD.
11	A	input	Channel select address bit A (LSB). Digital input; logic levels 0 = VSS, 1 = VDD.
12	CH3	bidirectional	Channel 3 analog in/out. Bidirectional analog switch terminal; connects to COM when address = 011 and INH = 0.
13	CH0	bidirectional	Channel 0 analog in/out. Bidirectional analog switch terminal; connects to COM when address = 000 and INH = 0.
14	CH1	bidirectional	Channel 1 analog in/out. Bidirectional analog switch terminal; connects to COM when address = 001 and INH = 0.
15	CH2	bidirectional	Channel 2 analog in/out. Bidirectional analog switch terminal; connects to COM when address = 010 and INH = 0.
16	VDD	power_in	Positive supply. VDD − VSS = 3V to 20V (performance degrades below 3V). Absolute maximum V+ to V− = 20V.

Key specifications

Parameter	Value
Type	8-channel analog mux / demux
Channels	8 (CH0-CH7 <-> COM)
Control	3-bit address A/B/C + INH inhibit
Signal range	Bipolar (VDD to VEE)
Supply (VDD)	3-18 V
Direction	Bidirectional (mux or demux)
Package	SOIC-16
Body (L×W×H)	9.9 × 3.9 × 1.75 mm

Ordering variants

Same part, different packaging or reel option.

CD4051BM (SOIC-16, tube)
CD4051BNSR (SO-16)

CAD (KiCad official)

Symbol: Analog_Switch:CD4051B
Footprint: Package_SO:SOIC-16_3.9x9.9mm_P1.27mm
3D model: SOIC-16 (KiCad packages3D)

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: Texas Instruments datasheet (39 pp, sha256 3fbac7b3f3463b15, retrieved 2026-08-17, tier: manufacturer)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF