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8-Bit Shift Registers W ith Latched 3-State Output

GENERAL DESCRIPTION
74HC595 is fabricated with high-speed silicon
gate CMOS technology. It contains an 8-bit
serial-in, serial or parallel-out shift register and an
8-bit D-type storage register with parallel 3-state
outputs. The shift and storage register have
independent clock inputs. Both the shift register
clock (SRCK) and storage register clock (RCK)
are positive-edge triggered.
The shift register has a direct overriding clear
input (SRCL), serial data input (SER), and serial
outputs for cascading. When the output-enable
(OE) input is high, the outputs are in the
high-impedance state. If both clocks are
connected together, the shift register always is
one clock pulse ahead of the storage register.

FEATURES
• 8-bit serial-in, parallel-out shift register with storage
• Shift register has direct clear
• 8-bit D-type storage register with parallel 3-state outputs
• Two independent clocks for shift and storage register
• Wide operating power supply voltage 2-6V
• Low input current < 1µA
• Low power consumption, Max. 80µA (74HC595)
• Output driving capacity ± 6 mA at 5V
• Typical propagation delay 13nS

LOGIC DIAGRAM



















C1
1D
R
C2
2R
2S
R
Q8’
Q8 Q7 Q6 Q5 Q4 Q3 Q2 Q1
15 1 2 3 4 5 6 7
9
SRCK
SER
SRCL
OE
11
14
10
RCK
12
13
3R
C2
2R
2S
R
C2
2R
2S
R
C2
2R
2S
R
C2
2R
2S
R
C2
2R
2S
R
C2
2R
2S
R
C3
3S
3R
C3
3S
3R
C3
3S
3R
C3
3S
3R
C3
3S
3R
C3
3S
3R
C3
3S
3R
C3
3S