MM74C923

更新时间： 2024-11-04 22:46:07

品牌	Logo	应用领域
美国国家半导体 - NSC		编码器
页数	文件大小	规格书
10页	220K
描述
16, 20-Key Encoder

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数据手册

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MM74C923 数据手册

July 1993

MM54C922/MM74C922 16-Key Encoder

MM54C923/MM74C923 20-Key Encoder

General Description

These CMOS key encoders provide 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 kX on resist-

ance 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 en-

tered 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.

An internal register remembers the last key pressed even

after the key is released. The TRI-STATE outputs provide

for easy expansion and bus operation and are LPTTL com-

patible.

Features

50 kX 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

TRI-STATE outpust LPTTL compatible

Wide supply range

3V to 15V

Low power consumption

Connection Diagrams

Pin Assignment for

Dual-In-Line Package

Pin Assignment

for SOIC

Pin Assignment for

DIP and SOIC Package

TL/F/6037–14

Top View

TL/F/6037–1

Order Number MM74C922

Top View

TL/F/6037–2

Top View

Order Number MM54C922 or

MM74C922

Order Number MM54C923 or

MM74C923

TRI-STATEÉ is a registered trademark of National Semiconductor Corporation.

1995 National Semiconductor Corporation

TL/F/6037

RRD-B30M105/Printed in U. S. A.

12 3 4 5 6 7...10

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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