鈥?/div>
Common serial data I/O pin (3-State)
DESCRIPTION
The 74F674 is a 16-bit shift register with serial and parallel load
capability and serial output. A single pin serves alternately as an
input for serial entry or as a 3-State serial output. In the serial out
mode the data recirculates in the register. Chip Select, Read/Write
and Mode inputs provide control flexibility. The 74F674 operates in
one of four modes, as indicated in the Function table.
Hold:
A High signal on the Chip Select (CS) input prevents clocking
and forces the Serial Input/Output (SI/O) 3-State buffer into the high
impedance state.
Serial load:
Data present on the SI/O pin shifts into the register on
the falling edge of CP. Data enters the Q0 position and shifts toward
Q15 on successive clocks.
Serial output:
The SI/O 3-State buffer is active and the register
contents are shifted out from Q15 and simultaneously shifted back
into Q0.
Parallel load:
Data present on D0鈥揇15 is entered into the register
on the falling edge of CP. The SI/O 3-State buffer is active and
represents the Q15 output. To prevent false clocking, CP must be
Low during a Low-to-High transition of CS.
PIN CONFIGURATION
CS
CP
R/W
NC
M
SI/O
D0
D1
D2
1
2
3
4
5
6
7
8
9
24 V
CC
23 D15
22 D14
21 D13
20 D12
19 D11
18 D10
17 D9
16 D8
15 D7
14 D6
13 D5
D3 10
D4 11
GND 12
SF01188
TYPE
74F674
TYPICAL f
MAX
95MHz
TYPICAL SUPPLY
CURRENT
(TOTAL)
55mA
ORDERING INFORMATION
DESCRIPTION
24-Pin Plastic Slim DIP
(300mil)
24-Pin Plastic SOL
COMMERCIAL RANGE
V
CC
= 5V
鹵10%,
T
amb
= 0擄C to +70擄C
N74F674N
N74F674D
INPUT AND OUTPUT LOADING AND FAN-OUT TABLE
PINS
D0鈥揇15
CS
CP
M
R/W
SI/O
Parallel data inputs
Chip Select input (active Low)
Clock Pulse input (active falling edge)
Mode select input
Read/Write input
Serial data input or
Serial 3-state output
NOTE:
One (1.0) FAST Unit Load is defined as: 20碌A(chǔ) in the High state and 0.6mA in the Low state.
DESCRIPTION
74F(U.L.)
HIGH/LOW
1.0/1.0
1.0/1.0
1.0/1.0
1.0/1.0
1.0/1.0
3.5/1.0
150/40
LOAD VALUE
HIGH/LOW
20碌A(chǔ)/0.6mA
20碌A(chǔ)/0.6mA
20碌A(chǔ)/0.6mA
20碌A(chǔ)/0.6mA
20碌A(chǔ)/0.6mA
70mA/0.6mA
3.0mA/24mA
1989 Feb 05
1
853鈥?248 92263
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