hef4557b NXP Semiconductors, hef4557b Datasheet - Page 2

• Manufacturer Part Number: hef4557b
• Description: 1-to-64 Bit Variable Length Shift Register
• Manufacturer: NXP Semiconductors

Philips Semiconductors
DESCRIPTION
The HEF4557B is a static clocked serial shift register
whose length may be programmed to be any number of
bits between 1 and 64. The number of bits selected is
equal to the sum of the subscripts of the enabled length
control inputs (L
data may be selected from the D
the A/B select input. This feature is useful for recirculation
PINNING
January 1995
D
A/B
CP
CP
MR
L
O, O
1
A
1-to-64 bit variable length shift register
, D
to L
0
1
B
32
1
, L
Fig.2 Pinning diagram.
data inputs
select data input
clock input
clock enable input
asynchronous master reset
bit-length control inputs
buffered outputs
2
, L
4
, L
8
, L
16
and L
A
or D
32
B
) plus one. Serial
data inputs with
Fig.1 Functional diagram.
2
purposes. Information on D
register position and all the data in the register is shifted
one position to the right on the LOW to HIGH transition of
CP
of CP
resets the register and forces O to LOW and O to HIGH,
independent of the other inputs.
FAMILY DATA, I
See Family Specifications
HEF4557BP(N):
HEF4557BD(F):
HEF4557BT(D):
( ): Package Designator North America
0
while CP
1
while CP
1
is LOW or on the HIGH to LOW transition
0
DD
is HIGH. A HIGH on master reset (MR)
LIMITS category LSI
16-lead DIL; plastic
16-lead DIL; ceramic (cerdip)
16-lead SO; plastic
(SOT38-1)
(SOT74)
(SOT109-1)
A
or D
B
Product specification
is shifted into the first
HEF4557B
LSI