Philips Semiconductors

Product specification

74F674

16-bit serial/parallel-in, serial-out shift register (3-State)

1

1989 Feb 05

853–1248 92263

FEATURES

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–D15 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

24

1

CS

23

22

21

20

19

18

17

16

10

15

9

8

7

6

5

4

3

2

D15

D14

D11

D10

D9

D8

CP

M

SI/O

D1

D2

D3

D13

D12

NC

R/W

SF01188

D0

D7

14

12

13

11

D6

D4

GND

D5

TYPE

TYPICAL SUPPLY

CURRENT

(TOTAL)

74F674

95MHz

55mA

ORDERING INFORMATION

DESCRIPTION

COMMERCIAL RANGE

24-Pin Plastic Slim DIP

(300mil)

N74F674N

24-Pin Plastic SOL

N74F674D

INPUT AND OUTPUT LOADING AND FAN-OUT TABLE

PINS

DESCRIPTION

74F(U.L.)

HIGH/LOW

LOAD VALUE

HIGH/LOW

D0–D15

Parallel data inputs

1.0/1.0

20

µA/0.6mA

CS

Chip Select input (active Low)

1.0/1.0

20

µA/0.6mA

CP

Clock Pulse input (active falling edge)

1.0/1.0

20

µA/0.6mA

M

Mode select input

1.0/1.0

20

µA/0.6mA

R/W

Read/Write input

1.0/1.0

20

µA/0.6mA

SI/O

Serial data input or

3.5/1.0

70mA/0.6mA

SI/O

Serial 3-state output

150/40

3.0mA/24mA

NOTE: One (1.0) FAST Unit Load is defined as: 20

µA in the High state and 0.6mA in the Low state.