1
CAT25C128/256
128K/256K-Bit SPI Serial CMOS E
2
PROM
FEATURES
a73 5 MHz SPI Compatible
a73 1.8 to 6.0 Volt Operation
a73 Hardware and Software Protection
a73 Zero Standby Current
a73 Low Power CMOS Technology
a73 SPI Modes (0,0 &1,1)
a73 Commercial, Industrial and Automotive
Temperature Ranges
a73 100,000 Program/Erase Cycles
a73 100 Year Data Retention
a73 Self-Timed Write Cycle
a73 8-Pin DIP/SOIC, 16-Pin SOIC, 14-Pin TSSOP
and 20-Pin TSSOP
a73 64-Byte Page Write Buffer
a73 Block Write Protection
– Protect 1/4, 1/2 or all of E
2
PROM Array
PIN CONFIGURATION
DIP Package (P)
PIN FUNCTIONS
Pin Name Function
SO Serial Data Output
SCK Serial Clock
WP Write Protect
VCC +1.8V to +6.0V Power Supply
VSS Ground
CS Chip Select
SI Serial Data Input
HOLD Suspends Serial Input
NC No Connect
BLOCK DIAGRAM
© 2001 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
DESCRIPTION
The CAT25C128/256 is a 128K/256K-Bit SPI Serial
CMOS E
2
PROM internally organized as 16Kx8/32Kx8
bits. Catalyst’s advanced CMOS Technology substan-
tially reduces device power requirements. The
CAT25C128/256 features a 64-byte page write buffer.
The device operates via the SPI bus serial interface and
is enabled though a Chip Select (CS). In addition to the
Chip Select, the clock input (SCK), data in (SI) and data
out (SO) are required to access the device. The HOLD
pin may be used to suspend any serial communication
without resetting the serial sequence. The CAT25C128/
256 is designed with software and hardware write pro-
tection features including Block Lock protection. The
device is available in 8-pin DIP, 8-pin SOIC, 16-pin
SOIC, 14-pin TSSOP and 20-pin TSSOP packages.
TSSOP Package (U20)
SENSE AMPS
SHIFT REGISTERS
SPI
CONTROL
LOGIC
WORD ADDRESS
BUFFERS
I/O
CONTROL
E
2
PROM
ARRAY
COLUMN
DECODERS
XDEC
HIGH VOLTAGE/
TIMING CONTROL
SO
25C128 F02
STATUS
REGISTER
BLOCK
PROTECT
LOGIC
CONTR
OL LOGIC
DATA IN
STORAGE
SI
CS
WP
HOLD
SCK
SOIC Package (S, K)
V
SS
SO
WP
V
CC
HOLD
SCK
SI
1
2
3
4
8
7
6
5
CS
SO
WP
CS VCC
HOLD
SCK
SI
1
2
3
4
8
7
6
5V
SS
Doc. No. 25088-00 1/01
CS
WP
HOLD
VCC
NC
NC
NC NC
SO
NC
NC
V
SS
SCK
SI
1
2
3
4
5
6
7 8
9
10
11
12
13
14
SOIC Package (S16)
NC NC
CS
WP
HOLD
HOLD
VCC
NC
NC
NC
NC NC
NC
SO
NC
NC
SO
V
SS
SCK
SI
1
2
3
4
5
6
7
8
9
10 11
12
13
14
15
16
17
18
19
20
TSSOP Package (U14)
CS
NC
1
2
3
4
14
13
12
11
NC
NC
NC
5
6
710
98
NC
SCK
V
SS
SI
NC
WP
VCC
HOLDSO 15
16
NCNC
Note: CAT25C256 not available in 8-Lead S or U packages.