74hc4051-8channel-analog-multiplexer

Important Note

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74HC4051 8-Channel Analog Multiplexer/Demultiplexer

Details

• Location: Cabinet-3, Bin 34, Section D
• Category: Logic Gates
• Quantity: 15
• Status: Available
• Package: 16-pin DIP (Dual In-line Package)
• Datasheet: 74HC4051 Datasheet

Description

The 74HC4051 is a CMOS 8-Channel Analog Multiplexer/Demultiplexer that functions as a single-pole, 8-throw (SP8T) analog switch. It can route one of eight input signals to a single output (multiplexer mode) or route a single input to one of eight outputs (demultiplexer mode). The channel selection is controlled by a 3-bit binary address.

Key Features

• 8-Channel Operation: Single-pole, 8-throw analog switch
• Bidirectional: Can function as multiplexer or demultiplexer
• Digital Control: 3-bit address selects active channel (A0, A1, A2)
• Enable Input: Active-low enable for turning all channels off
• Wide Signal Range: Handles both analog and digital signals
• Low On-Resistance: Typically 120Ω at VCC = 4.5V
• CMOS Technology: Low power consumption and high noise immunity
• 74HC Series: High-speed CMOS logic family

Technical Specifications

• Package: 16-pin DIP (0.6” width)
• Technology: High-Speed CMOS (74HC Series)
• Supply Voltage: 2V - 6V (typical 5V operation)
• On-Resistance: 120Ω typical at VCC = 4.5V
• Channel Selection: 3-bit binary address (8 combinations)
• Propagation Delay: Typically 10ns
• Operating Temperature: -40°C to +85°C
• Power Consumption: Very low static power
• Input/Output Voltage Range: 0V to VCC

Typical Pinout (DIP-16)

    74HC4051
    ┌─────────────┐
A4  │1          16│ VCC
A6  │2          15│ A2
A   │3          14│ A1
A7  │4          13│ A0
A5  │5          12│ A3
E   │6          11│ S0
VEE │7          10│ S1
GND │8           9│ S2
    └─────────────┘

Pin Descriptions

• VCC (Pin 16): Positive supply voltage (+2V to +6V)
• GND (Pin 8): Ground (0V)
• VEE (Pin 7): Negative supply voltage (typically connected to GND)
• A (Pin 3): Common input/output terminal (multiplexer output)
• A0-A7 (Pins 13,14,15,12,1,2,4,5): Eight analog input/output channels
• S0-S2 (Pins 11,10,9): 3-bit address inputs for channel selection
• E (Pin 6): Enable/Inhibit input (active low enables multiplexer)

Channel Selection

Address Truth Table

S2	S1	S0	Selected Channel
0	0	0	A0 (Pin 13)
0	0	1	A1 (Pin 14)
0	1	0	A2 (Pin 15)
0	1	1	A3 (Pin 12)
1	0	0	A4 (Pin 1)
1	0	1	A5 (Pin 5)
1	1	0	A6 (Pin 2)
1	1	1	A7 (Pin 4)

Enable Control

• E = 0 (Low): Multiplexer enabled, selected channel connected to A
• E = 1 (High): All channels disabled, A is in high-impedance state

Operation Modes

Multiplexer Mode

• Multiple analog inputs (Y0-Y7) → Single output (Z)
• Address inputs select which input appears at output
• Common application: Analog input expansion for microcontrollers

Demultiplexer Mode

• Single analog input (Z) → Multiple outputs (Y0-Y7)
• Address inputs select which output receives the input signal
• Common application: Analog signal distribution

Applications

• Analog Input Expansion: Increase ADC channels for microcontrollers
• Sensor Multiplexing: Read multiple analog sensors with one ADC
• Signal Routing: Route audio or video signals
• Data Acquisition: Multi-channel data logging systems
• Instrumentation: Test equipment signal switching
• Audio Applications: Audio channel selection and mixing
• Communication Systems: Signal path selection
• Analog Computers: Analog signal processing

Circuit Examples

Basic Multiplexer

• Connect analog sensors to Y0-Y7
• Connect microcontroller ADC to Z
• Use digital outputs to control A0-A2
• Read different sensors by changing address

Demultiplexer Application

• Connect DAC output to Z
• Connect different loads to Y0-Y7
• Select output channel with address inputs
• Drive different analog outputs

Design Considerations

• Signal Levels: Input signals should not exceed VCC
• On-Resistance: Affects signal attenuation and accuracy
• Switching Time: Consider propagation delays in high-speed applications
• Power Supply: Use proper decoupling capacitors
• Address Timing: Ensure stable address before enabling
• Load Impedance: High impedance loads minimize signal loading

Advantages

• Versatile: Both multiplexer and demultiplexer operation
• Low Power: CMOS technology for minimal power consumption
• Simple Control: Standard digital logic levels
• Bidirectional: Signal can flow in either direction
• Multiple Channels: Eight channels in single package
• Fast Switching: High-speed CMOS for quick channel changes

Comparison with Similar ICs

74HC4051 vs CD4051

• 74HC4051: Faster switching, narrower voltage range (2V-6V)
• CD4051: Slower switching, wider voltage range (3V-18V)

74HC4051 vs 74HC4052

• 74HC4051: Single 8:1 multiplexer
• 74HC4052: Dual 4:1 multiplexer

74HC4051 vs 74HC4067

• 74HC4051: 8 channels, 3-bit address
• 74HC4067: 16 channels, 4-bit address

Tags

logic-gate, analog-multiplexer, demultiplexer, 8-channel, sp8t, cmos, 74hc-series, dip-16 cabinet-3 bin-34 section-d status-available

Notes

The 74HC4051 is part of the 74HC high-speed CMOS logic family and is widely used for:

• Arduino and microcontroller projects requiring analog input expansion
• Data acquisition systems
• Audio and video signal routing
• Instrumentation and test equipment
• Educational electronics projects

Modern alternatives and related parts:

• CD74HC4051: Texas Instruments version
• 74HCT4051: TTL-compatible inputs version
• ADG508: Precision analog multiplexer
• MAX4617: Low-voltage analog switches

The 74HC4051 is particularly popular in maker and hobbyist communities for expanding the analog input capabilities of microcontrollers like Arduino, allowing multiple sensors to share a single ADC input through time-division multiplexing.