CD4051BM Analog Switch: Pinout, CAD Model and Specification

The CD4051B analog multiplexers are digitally-controlled analog switches having low ON impedance and very low OFF leakage current. Control of analog signals up to 20 VP-P can be achieved by digital signal amplitudes of 4.5 V to 20 V (if VDD – VSS = 3 V, a VDD – VEE of up to 13 V can be controlled; for VDD – VEE level differences above 13 V, a VDD – VSS of at least 4.5 V is required). For example, if VDD = +4.5 V, VSS = 0 V, and VEE = –13.5 V, analog signals from –13.5 V to +4.5 V can be controlled by digital inputs of 0 V to 5 V. These multiplexer circuits dissipate extremely low quiescent power over the full VDD – VSS and VDD – VEE supply-voltage ranges, independent of the logic state of the control signals. When logic 1 is present at the inhibit input terminal, all channels are off.

The CD4051B device is a single 8-channel multiplexer having three binary control inputs, A, B, and C, and an inhibit input. The three binary signals select 1 of 8 channels to be turned on and connect one of the 8 inputs to the output.

Pin Functions CD4051B

PCB Symbol - Texas Instruments CD4051BM

PCB Footprint - Texas Instruments CD4051BM

3D Model - Texas Instruments CD4051BM

• Wide Range of Digital and Analog Signal Levels

– Digital: 3 V to 20 V

– Analog: ≤20 VP-P

• Low ON Resistance,125 Ω (Typical) Over 15 VP-P Signal Input Range for VDD – VEE = 18 V

• High OFF Resistance, Channel Leakage of ±100 pA (Typical) at VDD – VEE = 18 V

• Logic-Level Conversion for Digital Addressing

Signals of 3 V to 20 V (VDD – VSS = 3 V to 20 V) to Switch Analog Signals to 20 VP-P (VDD – VEE = 20 V) Matched Switch Characteristics, rON = 5 Ω (Typical) for VDD – VEE = 15 V Very Low Quiescent Power Dissipation Under All Digital-Control Input and Supply Conditions, 0.2 µW (Typical) at VDD – VSS = VDD – VEE = 10 V

• Binary Address Decoding on Chip

• 5 V, 10 V, and 15 V Parametric Ratings

• 100% Tested for Quiescent Current at 20 V

• Maximum Input Current of 1 µA at 18 V Over Full Package Temperature Range, 100 nA at 18 V and 25°C

• Break-Before-Make Switching Eliminates Channel Overlap

Functional Diagrams of CD4051B

Functional Block Diagram, CD4051B

• Analog and Digital Multiplexing and Demultiplexing

• A/D and D/A Conversion

• Signal Gating

• Factory Automation

• Televisions

• Appliances

• Consumer Audio

• Programmable Logic Circuits

• Sensors

Typical Application

One application of the CD4051B is to use it in conjunction with a microcontroller to poll a keypad. The figure below shows the basic schematic for such a polling system. The microcontroller uses the channel select pins to cycle through the different channels while reading the input to see if a user is pressing any of the keys. This is a very robust setup, allowing for multiple simultaneous key-presses with very little power consumption. It also utilizes very few pins on the microcontroller. The down side of polling is that the microcontroller must continually scan the keys for a press and can do little else during this process.

The CD4051B Being Used to Help Read Button Presses on a Keypad

TAPE AND REEL INFORMATION

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