MM74C923WM Fairchild Semiconductor, MM74C923WM Datasheet

IC ENCODER 20-KEY 20-SOIC

MM74C923WM

Manufacturer Part Number
MM74C923WM
Description
IC ENCODER 20-KEY 20-SOIC
Manufacturer
Fairchild Semiconductor
Series
74Cr
Type
20-Key Encoderr
Datasheet

Specifications of MM74C923WM

Circuit
1 x 9:4
Independent Circuits
1
Current - Output High, Low
15mA, 16mA
Voltage Supply Source
Single Supply
Voltage - Supply
3 V ~ 15 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
20-SOIC (7.5mm Width)
Product
Decoders, Encoders, Multiplexers & Demultiplexers
Logic Family
74C
Number Of Bits
4
Number Of Lines (input / Output)
8.0 / 5.0
Propagation Delay Time
150 ns at 5 V, 80 ns at 10 V, 60 ns at 15 V
Supply Voltage (max)
15 V
Supply Voltage (min)
3 V
Maximum Operating Temperature
+ 125 C
Minimum Operating Temperature
- 55 C
Mounting Style
SMD/SMT
Number Of Input Lines
8.0
Number Of Output Lines
5.0
Power Dissipation
700 mW
Applications
Switches, Keyboard
Logic Type
Key Encoder
No. Of Outputs
5
Supply Voltage Range
3V To 15V
Logic Case Style
SOIC
No. Of Pins
20
Operating Temperature Range
-40°C To +85°C
Rohs Compliant
Yes
Lead Free Status / RoHS Status
Lead free / RoHS Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
MM74C923WM
Manufacturer:
FAIRCHILD/仙童
Quantity:
20 000
© 2001 Fairchild Semiconductor Corporation
MM74C922WM
MM74C922N
MM74C923WM
MM74C923N
MM74C922 • MM74C923
16-Key Encoder • 20-Key Encoder
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 k
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.
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.
Ordering Code:
Device also available in Tape and Reel. Specify by appending suffix letter “X” to the ordering code.
Connection Diagrams
Order Number
Pin Assignment for DIP
Package Number
MM74C922
Top View
M20B
M20B
N18B
N20A
on resistance to be used. No
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" Wide
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
DS006037
Features
50 k
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:
Low power consumption
Package Description
maximum switch on resistance
Pin Assignment for SOIC
MM74C922
Top View
3V to 15V
October 1987
Revised April 2001
www.fairchildsemi.com

Related parts for MM74C923WM

MM74C923WM Summary of contents

Page 1

... M20B 20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" Wide MM74C922N N18B 18-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" Wide MM74C923WM M20B 20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" Wide MM74C923N N20A 20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide Device also available in Tape and Reel. Specify by appending suffix letter “ ...

Page 2

Connection Diagrams (Continued) Truth Tables (Pins 0 through 11) Switch Position Y1, X1 Y1, X2 Y1, X3 Y1, X4 Y2 ...

Page 3

Block Diagram 3 www.fairchildsemi.com ...

Page 4

Absolute Maximum Ratings Voltage at Any Pin V 0. Operating Temperature Range MM74C922, MM74C923 Storage Temperature Range Power Dissipation ( Dual-In-Line Small Outline Operating V Range Lead Temperature (Soldering, 10 seconds) DC ...

Page 5

DC Electrical Characteristics Symbol Parameter V Logical “0” Output Voltage OUT(0) OUTPUT DRIVE (See Family Characteristics Data Sheet) (Short Circuit Current) I Output Source Current SOURCE (P-Channel) I Output Source Current SOURCE (P-Channel) I Output Sink Current SINK (N-Channel) I ...

Page 6

Switching Time Waveforms T1 T2 RC, T3 0.7 RC, where R 10k and C is external capacitor at KBM input. www.fairchildsemi.com FIGURE 1. FIGURE 2. 6 ...

Page 7

Typical Performance Characteristics Typical Any Y Input rp IN Typical SCAN OSC Typical Applications Synchronous Handshake (MM74C922) The keyboard may be synchronously scanned by omitting the capacitor at osc. and driving osc. directly ...

Page 8

Asynchronous Data Entry Onto Bus (MM74C922) Outputs are in 3-STATE until key is pressed, then data is placed on bus. When key is released, outputs return to 3-STATE. Expansion to 32 Key Encoder (MM74C922) Theory of Operation The MM74C922/MM74C923 Keyboard ...

Page 9

Physical Dimensions inches (millimeters) unless otherwise noted 20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300" Wide Package Number M20B 9 www.fairchildsemi.com ...

Page 10

Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 18-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300” Wide www.fairchildsemi.com Package Number N18B 10 ...

Page 11

Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and Fairchild reserves the right ...

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