Fairchild MM74C90, MM74C93 service manual
查询MM74C90供应商
MM74C90 • MM74C93
4-Bit Decade Counter • 4-Bit Binary Counter
MM74C90 • MM74C93 4-Bit Decade Counter • 4-Bit Binary Counter
October 1987
Revised January 1999
General Description
The MM74C90 decad e counter and the M M74C93 binar y
counter and comple mentary MOS (CMO S) integrated circuits constructed with N- and P-channel enhancement
mode transistors. The 4-bit decade counter can reset to
zero or preset to nine by applying appropriate logic level on
, R02, R91 and R92 inputs. Also, a separate flip-flop
the R
01
on the A-bit enables the user to op erat e it as a di vide -by-2,
5 or 10 frequency counter. The 4-bit bina r y counte r can be
reset to zero by applying h igh logic level on inputs R
, and a separate flip-f lop on the A- bit enables the user
R
02
01
to operate it as a divide-by-2, -8, or -16 divider. Counting
occurs on the negative going edge of the input pulse.
All inputs are protected against static discharge damage.
Features
■ Wide supply voltage range: 3V to 15V
■ Guaranteed noise margin: 1V
■ High noise immunity: 0.45 V
■ Low power compatibility:
and
Fan out of 2 TTL driving 74L
■ The MM74C93 follows the MM74L93 Pinout
CC
(typ.)
Ordering Code:
Order Number Package Number Package Description
MM74C90N N14A 14-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300” Wide
MM74C93N N14A 14-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300” Wide
Connection Diagrams
Pin Assignments for DIP
MM74C90
MM74C93
Top View
© 1999 Fairchild Semiconductor Corporation DS005889.prf www.fairchildsemi.com
Top V iew
Logic Diagrams
MM74C90 • MM74C93
Truth Tables
MM74C90 MM74C93
MM74C90 4-Bit Decade Counter BCD Count Sequence
Count Output
Q
DQCQBQA
0LLLL
1LLLH
2LLHL
3LLHH
4LHLL
5LHLH
6LHHL
7LHHH
8HLLL
9HLLH
Output QA is connected to Input B for BCD count.
H = HIGH Level
L = LOW Level
X = Irrelevant
MM74C93 4-Bit Binary Counter Binary Count Sequence
Count Output
Q
DQCQBQA
0 LLLL
1LLLH
2LLHL
3LLHH
4LHLL
5LHLH
6LHHL
7 LHHH
8 HLLL
9HLLH
10 H L H L
11 H L H H
12 H H L L
13 H H L H
14 H H H L
15 HHHH
Output QA is connected to input B for binary count sequence.
H = HIGH Level
L = LOW Level
X = Irrelevant
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Function Tables
Reset/Count Function Table
Reset Inputs Output
R
01R02R91R92
QDQ
C
QBQ
A
HHLXLLLL
HHXLLLLL
XXHHHLLH
X L X L Count
LXLX Count
L X X L Count
X L L X Count
Reset/Count Function Table
Reset Output
Inputs
R
R
01
Q
02
Q
D
Q
C
Q
B
A
HHLLLL
L X Count
X L Count
MM74C90 • MM74C93
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