ZHCSJS2N November 1997 – April 2024 CD54HC4051 , CD54HC4052 , CD54HC4053 , CD54HCT4051 , CD74HC4051 , CD74HC4052 , CD74HC4053 , CD74HCT4051 , CD74HCT4052 , CD74HCT4053
PRODUCTION DATA
- 1
- 1 特性
- 2 应用
- 3 说明
- 4 Pin Configuration and Functions
-
5 Specifications
- 5.1 Absolute Maximum Ratings
- 5.2 ESD Ratings
- 5.3 Thermal Information
- 5.4 Recommended Operating Conditions
- 5.5 Electrical Characteristics: HC Devices
- 5.6 Electrical Characteristics: HCT Devices
- 5.7 Switching Characteristics, VCC = 5V
- 5.8 Switching Characteristics, CL = 50pF
- 5.9 Analog Channel Specifications
- 5.10 Typical Characteristics
- 6 Parameter Measurement Information
- 7 Detailed Description
- 8 Application and Implementation
- 9 Device and Documentation Support
- 10Revision History
- 11Mechanical, Packaging, and Orderable Information
8.2 Typical Application
One application of the CD74HC4051 device is used 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 is a very robust setup that allows for simultaneous key presses with very little power consumption. It also uses very few pins on the microcontroller. The down side of polling is that the microcontroller must frequently scan the keys for a press.
Figure 8-1 CD74HC4051 Being Used to Help Read Button Presses on a Keypad