
TL/F/9535
5
January 1995
54F/74F402 Serial Data Polynomial
Generator/Checker
General Description
The ’F402 expandable Serial Data Polynomial generator/
checker is an expandable version of the ’F401. It provides
an advanced tool for the implementation of the most widely
used error detection scheme in serial digital handling sys-
tems. A 4-bit control input selects one-of-six generator poly-
nomials. The list of polynomials includes CRC-16, CRC-
CCITT and Ethernet
é
, as well as three other standard poly-
nomials (56
th
order, 48
th
order, 32
nd
order). Individual clear
and preset inputs are provided for floppy disk and other
applications. The Error output indicates whether or not a
transmission error has occurred. The CWG Control input
inhibits feedback during check word transmission. The
’F402 is compatible with FAST
é
devices and with all TTL
families.
Features
Y
Guaranteed 30 MHz data rate
Y
Six selectable polynomials
Y
Other polynomials available
Y
Separate preset and clear controls
Y
Expandable
Y
Automatic right justification
Y
Error output open collector
Y
Typical applications:
Floppy and other disk storage systems
Digital cassette and cartridge systems
Data communication systems
Commercial
Military
Package
Number
Package Description
74F402PC
N16E
16-Lead (0.300
×
Wide) Molded Dual-In-Line
54F402DM (Note 1)
J16A
16-Lead Ceramic Dual-In-Line
54F402FM (Note 1)
W16A
16-Lead Cerpack
54F402LM (Note 1)
E20A
20-Lead Ceramic Leadless Chip Carrier, Type C
Note 1:
Military grade device with environmental and burn-in processing. Use suffix
e
DMQB, FMQB and LMQB.
Logic Symbol
Connection Diagrams
TL/F/9535–4
Pin Assignment
for DIP, SOIC and Flatpak
TL/F/9535–1
Pin Assignment
for LCC
TL/F/9535–2
TRI-STATE
é
is a registered trademark of National Semiconductor Corporation.
Ethernet
é
is a registered trademark of Xerox Corporation.
C
1995 National Semiconductor Corporation
RRD-B30M105/Printed in U. S. A.