Description

The CD405xB analog multiplexers and demultiplexers are digitally-controlled analog switches having low ON impedance and very low OFF leakage current. 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.

 

Features

• Wide range of digital and analog signal levels:–Digital: 3V to 20V–Analog: ≤ 20VP-P
• Single supply range : 3V to 20V (performance degrades for VDD < 3V)
• Dual Supply range: ± 3V to ± 10V
• Low ON resistance, 125Ω (typical) over input range for VDD = 15V
• Low channel leakage of ±10pA (typical) at VDD = 15V
• Low quiescent power dissipation : 0.2µW (typical)
• Break-before-make switching eliminates channel overlap
• Bidirectional signal path
• ESD protection HBM: 3000V, CDM: 2000V
• Pin compatible with industry standard 4051 muxes

 

Applications

• Analog and digital multiplexing and demultiplexing
• Analog to digital and digital to analog conversion
• Signal gating
• Factory automation
• Televisions
• Appliances
• Consumer audio
• Programmable logic circuits
• Sensors

 

Overview

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.
The CD4052B device is a differential 4-channel multiplexer having two binary control inputs, A and B, and an inhibit input. The two binary input signals select 1 of 4 pairs of channels to be turned on and connect the analog inputs to the outputs.
The device is a triple 2-channel multiplexer having three separate digital control inputs, A, B, and C, and an inhibit input. Each control input selects one of a pair of channels which are connected in a single-pole, double-throw configuration.
When these devices are used as demultiplexers, the CHANNEL IN/OUT terminals are the outputs and the COMMON OUT/IN terminals are the inputs.

 

Feature Description

The CD405xB line of multiplexers and demultiplexers can accept a wide range of digital and analog signal levels. Digital signals range from 3V to 20V, and analog signals are accepted at levels ≤ 20V. The devices have low ON resistance, typically 125Ω over 15VP-P signal input range for VDD – VEE = 18V. This feature allows for very little signal loss through the switch.
The CD405xB devices also have high OFF resistance, which keeps from the devices from wasting power when the switch is in the OFF position, with typical channel leakage of ±100pA at VDD – VEE = 18V.
Binary address decoding on the chip makes channel selection simple. When channels are changed, a break-before-make system eliminates channel overlap.

 

Typical Application

One application of the CD4051B is to use it in conjunction with a microcontroller to poll a keypad. 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 application is a very robust setup, allowing for multiple simultaneous key-presses with very little power consumption. This setup also uses 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.

 

Power Supply Recommendations

The power supply can be any voltage between the minimum and maximum supply voltage rating located in the Electrical Characteristics.
Each VCC terminal should have a good bypass capacitor to prevent power disturbance. For devices with a single supply, a 0.1μF bypass capacitor is recommended. If there are multiple pins labeled VCC, then a 0.01μF or 0.022μF capacitor is recommended for each VCC because the VCC pins will be tied together internally. For devices with dual supply pins operating at different voltages, for example VCC and VDD, a 0.1µF bypass capacitor is recommended for each supply pin. It is acceptable to parallel multiple bypass capacitors to reject different frequencies of noise. 0.1μF and 1μF capacitors are commonly used in parallel. The bypass capacitor should beinstalled as close to the power terminal as possible for best results.