8 Application and Implementation

Note

Information in the following applications sections is not part of the TI component specification,

and TI does not warrant its accuracy or completeness. TI’s customers are responsible for

determining suitability of components for their purposes, as well as validating and testing their design

implementation to confirm system functionality.

8.1 Application Information

The CD4053B-Q1 multiplexers and demultiplexers can be used for a wide variety of applications.

8.2 Typical Application

One application of the CD4053B-Q1 is to use it in conjunction with a microcontroller to poll a keypad. Figure

8-1 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 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.

CD4053B-Q1

INH

A

B

C

C B A

X X 0

ax

ay

bx

by

cx

cy

X X 1

X 0 X

X 1 X

0 X X

1 X X

VDD

5V

VEE

VSS

a

b

c

Microcontroller

Inputs

Channel Select

3.3V

Figure 8-1. The CD4053B-Q1 Being Used to Help Read Button Presses on a Keypad

8.2.1 Design Requirements

These devices use CMOS technology and have balanced output drive. Take care to avoid bus contention

because it can drive currents that would exceed maximum limits. The high drive will also create fast edges into

light loads, so routing and load conditions should be considered to prevent ringing.

8.2.2 Detailed Design Procedure

1. Recommended Input Conditions:

• For switch time specifications, see propagation delay times in Section 5.5.

• Inputs should not be pushed more than 0.5V above VDD or below VEE.

• For input voltage level specifications for control inputs, see VIH and VIL in Section 5.5.

2. Recommended Output Conditions:

• Outputs should not be pulled above VDD or below VEE.

3. Input or output current consideration:

• The CD405xB-Q1 series of parts do not have internal current drive circuitry and thus cannot sink or

source current. Any current will be passed through the device.

CD4053B-Q1

SCHS469 – MARCH 2025

www.ti.com

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