Preliminary
CAT35C804A
4K-Bit Secure Access Serial E2PROM
FEATURES
■ Single 5V Supply
■ Commercial, Industrial and Automotive
Temperature Ranges
■ Password READ/WRITE Protection: 1 to 8 Bytes
■ Memory Pointer WRITE Protection
■ Sequential READ Operation
■ I/O Speed: 9600 Baud
–Clock Frequency: 4.9152 MHz Xtal
■ Low Power Consumption:
–Active: 3 mA
■ 256 x16 or 512 x 8 Selectable Serial Memory
■ UART Compatible Asynchronous Protocol
■ 100,000 Program/Erase Cycles
–Standby: 250 µA
■ 100 Year Data Retention
DESCRIPTION
The CAT35C804A is a 4K-bit Serial E2PROM that safe-
guards stored data from unauthorized access by use of
a user selectable (1 to 8 byte) access code and a
movablememorypointer. Twooperatingmodesprovide
unprotected and password-protected operation allow-
ing the user to configure the device as anything from a
ROM to a fully protected no-access memory. The
CAT35C804A uses a UART compatible asynchronous
protocol and has a Sequential Read feature where data
can be sequentially clocked out of the memory array.
The device is available in 8-pin DIP or 16-pin SOIC
packages.
BLOCK DIAGRAM
PIN CONFIGURATION
DIP Package (P)
SOIC Package (J)
1
2
3
4
8
7
6
5
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
CS
CLK
DI
V
NC
NC
CS
CLK
DI
NC
NC
CC
V
CC
PE
GND
-
ERR
GND
V
64-BIT ACCESS CODE
CC
&
DO
PE
CONTROL BLOCK
ERR
GND
NC
DO
CLK
PE
SERIAL
COMMUNI-
CATION
DO
NC
NC
NC
CS
DI
BLOCK
4K-BIT EEPROM
ARRAY
5074 FHD F01
PIN FUNCTIONS
R/W
BUFFER
ADDRESS
DECODER
Pin Name
Function
INSTRUCTION
REGISTER
CS
Chip Select
DO(1)
CLK
DI(1)
PE
Serial Data Output
Clock Input
INSTRUCTION
DECODER
ADDRESS
REGISTER
ERR
Serial Data Input
Parity Enable
STATUS
REGISTER
MEMORY
POINTER
ERR
VCC
GND
Error Indication Pin
+5V Power Supply
Ground
35C804 F02
Note:
(1) DI, DO may be tied together to form a common I/O.
© 1998 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
Doc. No. 25043-00 2/98
1