hef4021b NXP Semiconductors, hef4021b Datasheet - Page 2

• Manufacturer Part Number: hef4021b
• Description: 8-bit Static Shift Register
• Manufacturer: NXP Semiconductors

Philips Semiconductors
DESCRIPTION
The HEF4021B is an 8-bit static shift register
(parallel-to-serial converter) with a synchronous serial
data input (D
HIGH parallel load input (PL), eight asynchronous parallel
data inputs (P
the last three stages (0
PINNING
January 1995
PL
P
D
CP
O
0
S
8-bit static shift register
5
to P
to O
7
7
S
), a clock input (CP), an asynchronous active
0
to P
Fig.2 Pinning diagram.
parallel load input
parallel data inputs
serial data input
clock input (LOW to HIGH edge-triggered)
buffered parallel outputs from the last three stages
7
) and buffered parallel outputs from
5
to O
7
).
Fig.1 Functional diagram.
2
Each register stage is a D-type master-slave flip-flop with
a set direct/clear direct input. Information on P
asynchronously loaded into the register while PL is HIGH,
independent of CP and DS. When PL is LOW, data on
D
in the register is shifted one position to the right on the
LOW to HIGH transition of CP. Schmitt-trigger action in the
clock input makes the circuit highly tolerant to slower clock
rise and fall times.
FAMILY DATA, I
See Family Specifications
HEF4021BP(N):
HEF4021BD(F):
HEF4021BT(D):
( ): Package Designator North America
S
is shifted into the first register position and all the data
DD
LIMITS category MSI
16-lead DIL; plastic
16-lead DIL; ceramic (cerdip)
16-lead SO; plastic
(SOT38-1)
(SOT74)
(SOT109-1)
Product specification
HEF4021B
0
to P
MSI
7
is