MM74C923

更新时间： 2024-11-04 22:46:07

品牌	Logo	应用领域
飞兆/仙童 - FAIRCHILD		编码器
页数	文件大小	规格书
10页	116K
描述
16-Key Encoder 20-Key Encoder

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中文翻译

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数据手册

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MM74C923 数据手册

October 1987

Revised January 1999

MM74C922 • MM74C923

16-Key Encoder • 20-Key Encoder

An internal register remembers the last key pressed even

after the key is released. The 3-STATE outputs provide for

easy expansion and bus operation and are LPTTL compat-

ible.

General Description

The MM74C922 and MM74C923 CMOS key encoders pro-

vide all the necessary logic to fully encode an array of

SPST switches. The keyboard scan can be implemented

by either an external clock or external capacitor. These

encoders also have on-chip pull-up devices which permit

switches with up to 50 kΩ on resistance to be used. No

diodes in the switch array are needed to eliminate ghost

switches. The internal debounce circuit needs only a single

external capacitor and can be defeated by omitting the

capacitor. A Data Available output goes to a high level

when a valid keyboard entry has been made. The Data

Available output returns to a low level when the entered

key is released, even if another key is depressed. The Data

Available will return high to indicate acceptance of the new

key after a normal debounce period; this two-key roll-over

is provided between any two switches.

Features

■ 50 kΩ maximum switch on resistance

■ On or off chip clock

■ On-chip row pull-up devices

■ 2 key roll-over

■ Keybounce elimination with single capacitor

■ Last key register at outputs

■ 3-STATE output LPTTL compatible

■ Wide supply range: 3V to 15V

■ Low power consumption

Ordering Code:

Order Number

MM74C922N

Package Number

N18A

Package Description

18-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300” Wide

20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300” Wide

20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300” Wide

MM74C922WM

MM74C923WM

MM74C923N

M20B

N20A

Device also available in Tape and Reel. Specify by appending suffix letter “X” to the ordering code.

Connection Diagrams

Pin Assignment for DIP

Pin Assignment for SOIC

Top View

MM74C922

Top View

MM94C922

DS006037.prf

www.fairchildsemi.com

12 3 4 5 6 7...10

中文翻译

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与MM74C923相关器件

型号	品牌	获取价格	描述	数据表
MM74C923J	ROCHESTER	获取价格	Encoder, CMOS Series, 9-Bit, CMOS, CDIP20, CERAMIC, DIP-20
MM74C923J	NSC	获取价格	IC CMOS SERIES, 9-BIT ENCODER, CDIP20, CERAMIC, DIP-20, Arithmetic Circuit
MM74C923M	FAIRCHILD	获取价格	Encoder, CMOS, PDSO20
MM74C923M	ROCHESTER	获取价格	Encoder, CMOS Series, 9-Bit, CMOS, PDSO20, PLASTIC, SOP-20
MM74C923MX	TI	获取价格	CMOS SERIES, 9-BIT ENCODER, PDSO20, PLASTIC, SOP-20
MM74C923N	FAIRCHILD	获取价格	16-Key Encoder 20-Key Encoder
MM74C923N/A+	NSC	获取价格	IC,ENCODER,CMOS,DIP,20PIN,PLASTIC
MM74C923N/B+	NSC	获取价格	IC,ENCODER,CMOS,DIP,20PIN,PLASTIC
MM74C923N_NL	FAIRCHILD	获取价格	Encoder, CMOS Series, 9-Bit, CMOS, PDIP20, 0.300 INCH, PLASTIC, MS-001, DIP-20
MM74C923WM	ONSEMI	获取价格	Encoder