Philips HEF4894BT, HEF4894BP Datasheet
INTEGRATED CIRCUITS
DATA SH EET
For a complete data sheet, please also download:
•The IC04 LOCMOS HE4000B Logic
Family Specifications HEF, HEC
•The IC04 LOCMOS HE4000B Logic
Package Outlines/Information HEF, HEC
HEF4894B
12-stage shift-and-store register
LED driver
Product specification
File under Integrated Circuits, IC04
January 1995
Philips Semiconductors Product specification
12-stage shift-and-store register LED driver HEF4894B
APPLICATIONS
• Automotive
• Industrial
GENERAL DESCRIPTION
The HEF4894B is a 12 stage serial
shift register having a storage latch
associated with each stage for
strobing data from the serial input to
parallel LED driver outputs O
to
0
O11. Data is shifted on positive-going
clock transitions. The data in each
shift register stage is transferred to
the storage register when the strobe
(STR) input is HIGH. Data in the
storage register appears at the
outputs whenever the output enable
(EO) signal is HIGH.
Two serial outputs (Osand Os’) are
available for cascading a number of
HEF4894B devices. Data is available
at Oson positive-going clock edges to
allow high-speed operation in
cascaded systems in which the clock
rise time is fast. The same serial
information is available at Os’ on the
next negative-going clock edge and
provides cascading HEF4894B
devices when the clock rise time is
slow.
ORDERING AND PACKAGE INFORMATION
TYPE
NUMBER
PINS PIN POSITION MATERIAL CODE
PACKAGES
HEF4894BT 20 SO plastic SO20/SOT163A
HEF4894BP 20 DIL plastic DIL20/SOT146
PINNING
PIN SYMBOL NAME AND FUNCTION
1 STR strobe input
2 D data input
3 CP clock input
4, 5, 6, 7, 8, 9, 18,
O
0
to O
11
parallel outputs (open drain)
17, 16, 15, 14, 13
10 V
11, 12 O
ss
’ serial outputs
s,Os
ground
19 EO output enable input
20 V
DD
positive supply voltage
FAMILY DATA
See Family Specifications except for:
Rating for DC current into any open-drain output: 40 mA.
I
LIMITS category MSI: see Family Specifications.
DD
Preliminary pin assignment.
Fig.1 Pinning diagram.
January 1995 2
Fig.2 Functional diagram.
Philips Semiconductors Product specification
12-stage shift-and-store register LED driver HEF4894B
Fig.4 One D-latch.
Fig.3 Logic diagram.
FUNCTION TABLE
INPUTS
CP EO STR D O
PARALLEL
OUTPUTS
0
O
n
↑ LXX Z ZO
SERIAL
OUTPUTS
O
S
’nc
10
↓ LXX Z ZncO
↑ HLXncncO
↑ HHL ZO
↑ HHH LO
−1O10’nc
n
−1O10’nc
n
’nc
10
↓ HHH nc ncncO
Notes
1. H = HIGH state (the more positive voltage)
2. L = LOW state (the less positive voltage)
3. X = state is immaterial
4. ↑ = positive-going transition
5. ↓ = negative-going transition
6. Z = high impedance OFF state
7. nc = no change
8. O
’ = the information in the twelfth shift register stage.
11
OS’
11
11
At the positive clock edge the information in the 10thregister stage is
transferred to the 11thregister stage and the Osoutput.
January 1995 3
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