CTLST CAT24WC256KA-3TE13, CAT24WC256KA-1.8TE13, CAT24WC256K-TE13, CAT24WC256K-3TE13, CAT24WC256K-1.8TE13 Datasheet

1

A1

NC

V

SS

A1
NC

V

CC

WP
SCL
SDA

1
2
3
4

8
7
6
5

A0

V

CC

WP
SCL
SDA

1
2
3
4

8
7
6
5

V

SS

A0

PIN FUNCTIONS

Pin Name Function

A0, A1 Address Inputs
SDA Serial Data/Address
SCL Serial Clock
WP Write Protect
V

CC

+1.8V to +6.0V Power Supply

V

SS

Ground

NC No Connect

DESCRIPTION

The CAT24WC256 is a 256K-bit Serial CMOS E2PROM
internally organized as 32,768 words of 8 bits each.
Catalyst’s advanced CMOS technology substantially
reduces device power requirements. The

Preliminary

* Catalyst Semiconductor is licensed by Philips Corporation to carry the I2C Bus Protocol.

■ Write Protect Feature

– Entire Array Protected When WP at V

IH

■ 100,000 Program/Erase Cycles

■ 100 Year Data Retention

■ 8-Pin DIP or 8-Pin SOIC

CAT24WC256 features a 64-byte page write buffer. The
device operates via the I2C bus serial interface and is
available in 8-pin DIP or 8-pin SOIC packages.

PIN CONFIGURATION

BLOCK DIAGRAM

24WC256 F02

CAT24WC256

256K-Bit I2C Serial CMOS E2PROM

■ 1MHz I

2

C Bus Compatible*

■ 1.8 to 6 Volt Operation

■ Low Power CMOS Technology

■ 64-Byte Page Write Buffer

■ Self-Timed Write Cycle with Auto-Clear

■ Commercial, Industrial and Automotive

Temperature Ranges

FEATURES

DIP Package (P)

SOIC Package (K)

24WC256 F01

© 1998 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice

D

OUT

ACK

SENSE AMPS

SHIFT REGISTERS

CONTROL

LOGIC

WORD ADDRESS

BUFFERS

STAR T/STOP

LOGIC

STATE COUNTERS
SLAVE

ADDRESS
COMPARATORS

E2PROM
512X512

V

CC

EXTERNAL LOAD

COLUMN

DECODERS

XDEC

DATA IN STORAGE

HIGH VOL TAGE/

TIMING CONTROL

V

SS

WP

SCL

SDA

512

512

A0
A1

Doc. No. 25061-00 6/99 S-1

PreliminaryCAT24WC256

2

Doc. No. 25061-00 6/99 S-1

ABSOLUTE MAXIMUM RATINGS*

Temperature Under Bias ................. –55°C to +125°C

Storage Temperature....................... –65°C to +150°C

Voltage on Any Pin with

Respect to Ground

(1)

........... –2.0V to +V

CC

+ 2.0V

VCC with Respect to Ground ............... –2.0V to +7.0V

Package Power Dissipation

Capability (Ta = 25°C)................................... 1.0W

Lead Soldering Temperature (10 secs)............ 300°C

Output Short Circuit Current

(2)

........................ 100mA

*COMMENT

Stresses above those listed under “Absolute Maximum
Ratings” may cause permanent damage to the device.
These are stress ratings only, and functional operation of
the device at these or any other conditions outside of those
listed in the operational sections of this specification is not
implied. Exposure to any absolute maximum rating for
extended periods may affect device performance and
reliability.

RELIABILITY CHARACTERISTICS

Symbol Parameter Min. Max. Units Reference Test Method

N

END

(3)

Endurance 100,000 Cycles/Byte MIL-STD-883, Test Method 1033

T

DR

(3)

Data Retention 100 Years MIL-STD-883, Test Method 1008

V

ZAP

(3)

ESD Susceptibility 2000 Volts MIL-STD-883, Test Method 3015

I

LTH

(3)(4)

Latch-up 100 mA JEDEC Standard 17

CAPACITANCE TA = 25°C, f = 1.0 MHz, VCC = 5V

Symbol Test Max. Units Conditions

C

I/O

(3)

Input/Output Capacitance (SDA) 8 pF V

I/O

= 0V

C

IN

(3)

Input Capacitance (SCL, WP, A0, A1) 6 pF V

IN

= 0V

Note:
(1) The minimum DC input voltage is –0.5V. During transitions, inputs may undershoot to –2.0V for periods of less than 20 ns. Maximum DC

voltage on output pins is VCC +0.5V, which may overshoot to VCC + 2.0V for periods of less than 20ns.
(2) Output shorted for no more than one second. No more than one output shorted at a time.
(3) This parameter is tested initially and after a design or process change that affects the parameter.
(4) Latch-up protection is provided for stresses up to 100 mA on address and data pins from –1V to VCC +1V.
(5) Standby current (ISB ) = 0 µA (<900 nA).

Limits

Symbol Parameter Min. Typ. Max. Units Test Conditions

I

CC1

Power Supply Current - Read 1 mA f

SCL

= 100 KHz

VCC=5V

I

CC2

Power Supply Current - Write

3mAf

SCL

= 100KHz

VCC=5V

I

SB

(5)

Standby Current 0 µAVIN = GND or V

CC

VCC=5V

I

LI

Input Leakage Current 1 µAVIN = GND to V

CC

I

LO

Output Leakage Current 1 µAV

OUT

= GND to V

CC

V

IL

Input Low Voltage –1 VCC x 0.3 V

V

IH

Input High Voltage VCC x 0.7 VCC + 0.5 V

V

OL1

Output Low Voltage (VCC = +3.0V) 0.4 V IOL = 3.0 mA

V

OL2

Output Low Voltage (VCC = +1.8V) 0.5 V IOL = 1.5 mA

D.C. OPERATING CHARACTERISTICS

VCC = +1.8V to +6.0V, unless otherwise specified.

Preliminary CAT24WC256

3

Doc. No. 25061-00 6/99 S-1

Power-Up Timing

(2)(3)

Symbol Parameter Max. Units

t

PUR

Power-Up to Read Operation 1 ms

t

PUW

Power-Up to Write Operation 1 ms

Note:
(1) AC measurement conditions:
RL (connects to VCC): 0.3VCC to 0.7 V

CC

Input rise and fall times: < 50ns
Input and output timing reference voltages: 0.5 V

CC

(2) This parameter is tested initially and after a design or process change that affects the parameter.
(3) t

PUR

and t

PUW

are the delays required from the time VCC is stable until the specified operation can be initiated.

The write cycle time is the time from a valid stop
condition of a write sequence to the end of the internal
program/erase cycle. During the write cycle, the bus

interface circuits are disabled, SDA is allowed to remain
high, and the device does not respond to its slave
address.

A.C. CHARACTERISTICS

VCC = +1.8V to +6V, unless otherwise specified

Output Load is 1 TTL Gate and 100pF

Read & Write Cycle Limits

Symbol Parameter VCC=1.8V - 6.0V VCC=2.5V - 6.0V VCC=3.0V - 5.5V

Min. Max. Min. Max. Min. Max. Units

F

SCL

Clock Frequency 100 400 1000 kHz

t

AA

SCL Low to SDA Data Out 0.1 3.5 0.05 0.9 0.05 0.55 µs
and ACK Out

t

BUF

(2)

Time the Bus Must be Free Before 4.7 1.2 0.5 µs
a New Transmission Can Start

t

HD:STA

Start Condition Hold Time 4.0 0.6 0.25 µs

t

LOW

Clock Low Period 4.7 1.2 0.6 µs

t

HIGH

Clock High Period 4.0 0.6 0.4 µs

t

SU:STA

Start Condition Setup Time 4.0 0.6 0.25 µs
(for a Repeated Start Condition)

t

HD:DAT

Data In Hold Time 0 0 0 ns

t

SU:DAT

Data In Setup Time 100 100 100 ns

t

R

(2)

SDA and SCL Rise Time 1.0 0.3 0.3 µs

t

F

(2)

SDA and SCL Fall Time 300 300 100 ns

t

SU:STO

Stop Condition Setup Time 4.7 0.6 0.25 µs

t

DH

Data Out Hold Time 100 50 50 ns

t

WR

Write Cycle Time 10 10 5 ms

PreliminaryCAT24WC256

4

Doc. No. 25061-00 6/99 S-1

FUNCTIONAL DESCRIPTION

The CAT24WC256 supports the I2C Bus data transmis­sion protocol. This Inter-Integrated Circuit Bus protocol
defines any device that sends data to the bus to be a
transmitter and any device receiving data to be a re­ceiver. The transfer is controlled by the Master device
which generates the serial clock and all START and
STOP conditions for bus access. The CAT24WC256
operates as a Slave device. Both the Master device and
Slave device can operate as either transmitter or re­ceiver, but the Master device controls which mode is
activated.

PIN DESCRIPTIONS
SCL: Serial Clock

The serial clock input clocks all data transferred into or
out of the device.

SDA: Serial Data/Address

The bidirectional serial data/address pin is used to
transfer all data into and out of the device. The SDA pin
is an open drain output and can be wire-ORed with other
open drain or open collector outputs.

WP: Write Protect

This input, when tied to GND, allows write operations to
the entire memory. When this pin is tied to Vcc, the
entire memory is write protected. When left floating,
memory is unprotected.

5020 FHD F05

Figure 3. Start/Stop Timing

Figure 2. Write Cycle Timing

Figure 1. Bus Timing

START BIT

SDA

STOP BIT

SCL

5020 FHD F04

t

WR

STOP
CONDITION

START
CONDITION

ADDRESS

ACK8TH BIT

BYTE n

SCL

SDA

5020 FHD F03

t

HIGH

SCL

SDA IN

SDA OUT

t

LOW

t

F

t

LOW

t

R

t

BUF

t

SU:STO

t

SU:DAT

t

HD:DAT

t

HD:STA

t

SU:STA

t

AA

t

DH

A0, A1: Device Address Inputs

These pins are hardwired or left connected. When
hardwired, up to four CAT24WC256's may be addressed
on a single bus system. When the pins are left uncon­nected, the default values are zero.

Preliminary CAT24WC256

5

Doc. No. 25061-00 6/99 S-1

The features of the I2C bus protocol are defined as
follows:

(1) Data transfer may be initiated only when the bus is

not busy.

(2) During a data transfer, the data line must remain

stable whenever the clock line is high. Any changes
in the data line while the clock line is high will be
interpreted as a START or STOP condition.

START Condition

The START Condition precedes all commands to the
device, and is defined as a HIGH to LOW transition of
SDA when SCL is HIGH. The CAT24WC256 monitors
the SDA and SCL lines and will not respond until this
condition is met.

STOP Condition

A LOW to HIGH transition of SDA when SCL is HIGH
determines the STOP condition. All operations must end
with a STOP condition.

DEVICE ADDRESSING

The bus Master begins a transmission by sending a
START condition. The Master sends the address of the
particular slave device it is requesting. The five most
significant bits of the 8-bit slave address are fixed as
10100(Fig. 5). The CAT24WC256 uses the next two bits
as address bits. The address bits A1 and A0 allow as

Figure 4. Acknowledge Timing

5027 FHD F07

Figure 5. Slave Address Bits

5020 FHD F06

ACKNOWLEDGE

1

START

SCL FROM

MASTER

89

DATA OUTPUT

FROM TRANSMITTER

DATA OUTPUT

FROM RECEIVER

many as four devices on the same bus. These bits must
compare to their hardwired input pins. The last bit of the
slave address specifies whether a Read or Write opera­tion is to be performed. When this bit is set to 1, a Read
operation is selected, and when set to 0, a Write opera­tion is selected.

After the Master sends a START condition and the slave
address byte, the CAT24WC256 monitors the bus and
responds with an acknowledge (on the SDA line) when
its address matches the transmitted slave address. The
CAT24WC256 then performs a Read or Write operation
depending on the state of the R/W bit.

Acknowledge

After a successful data transfer, each receiving device is
required to generate an acknowledge. The Acknowledg­ing device pulls down the SDA line during the ninth clock
cycle, signaling that it received the 8 bits of data.

The CAT24WC256 responds with an acknowledge after
receiving a START condition and its slave address. If the
device has been selected along with a write operation,
it responds with an acknowledge after receiving each 8­bit byte.

When the CAT24WC256 begins a READ mode it trans­mits 8 bits of data, releases the SDA line, and monitors
the line for an acknowledge. Once it receives this ac­knowledge, the CAT24WC256 will continue to transmit
data. If no acknowledge is sent by the Master, the device

1 0100A1A0R/W

I2C BUS PROTOCOL

PreliminaryCAT24WC256

6

Doc. No. 25061-00 6/99 S-1

terminates data transmission and waits for a STOP
condition.

WRITE OPERATIONS

Byte Write

In the Byte Write mode, the Master device sends the
START condition and the slave address information
(with the R/W bit set to zero) to the Slave device. After
the Slave generates an acknowledge, the Master sends
two 8-bit address words that are to be written into the
address pointers of the CAT24WC256. After receiving
another acknowledge from the Slave, the Master device
transmits the data to be written into the addressed
memory location. The CAT24WC256 acknowledges
once more and the Master generates the STOP condi­tion. At this time, the device begins an internal program­ming cycle to nonvolatile memory. While the cycle is in
progress, the device will not respond to any request from
the Master device.

Page Write

The CAT24WC256 writes up to 64 bytes of data, in a
single write cycle, using the Page Write operation. The
page write operation is initiated in the same manner as
the byte write operation, however instead of terminating
after the initial byte is transmitted, the Master is allowed
to send up to 63 additional bytes. After each byte has
been transmitted, CAT24WC256 will respond with an
acknowledge, and internally increment the six low order
address bits by one. The high order bits remain un­changed.

If the Master transmits more than 64 bytes before sending
the STOP condition, the address counter ‘wraps around’,
and previously transmitted data will be overwritten.

When all 64 bytes are received, and the STOP condition
has been sent by the Master, the internal programming
cycle begins. At this point, all received data is written to
the CAT24WC256 in a single write cycle.

Acknowledge Polling

Disabling of the inputs can be used to take advantage of
the typical write cycle time. Once the stop condition is
issued to indicate the end of the host's write operation,
CAT24WC256 initiates the internal write cycle. ACK
polling can be initiated immediately. This involves issu­ing the start condition followed by the slave address for
a write operation. If CAT24WC256 is still busy with the
write operation, no ACK will be returned. If
CAT24WC256 has completed the write operation, an
ACK will be returned and the host can then proceed with
the next read or write operation.

WRITE PROTECTION

The Write Protection feature allows the user to protect
against inadvertent programming of the memory array.
If the WP pin is tied to VCC, the entire memory array is
protected and becomes read only. The CAT24WC256
will accept both slave and byte addresses, but the
memory location accessed is protected from program­ming by the device’s failure to send an acknowledge
after the first byte of data is received.

24WC256F09

Figure 7. Page Write Timing

Figure 6. Byte Write Timing

24WC256 F08

*

=Don't Care Bit

A15–A

8

SLAVE

ADDRESS

S

A

C

K

A
C
K

DATA

A
C
K

S
T

O

P

P

BUS ACTIVITY :

MASTER

SDA LINE

S
T
A
R
T

A7–A

0

BYTE ADDRESS

A
C
K

*

A15–A

8

SLAVE

ADDRESS

S

A
C
K

A
C
K

A
C
K

BUS ACTIVITY :

MASTER

SDA LINE

S
T
A
R
T

A7–A

0

BYTE ADDRESS

DATA n+63DATA

A
C
K

S
T
O
P

A
C
K

DATA n

A
C
K

P

A
C
K

*

*

=Don't Care Bit

Preliminary CAT24WC256

7

Doc. No. 25061-00 6/99 S-1

READ OPERATIONS

The READ operation for the CAT24WC256 is initiated in
the same manner as the write operation with one excep­tion, that R/W bit is set to one. Three different READ
operations are possible: Immediate/Current Address
READ, Selective/Random READ and Sequential READ.

Immediate/Current Address Read

The CAT24WC256’s address counter contains the ad­dress of the last byte accessed, incremented by one. In
other words, if the last READ or WRITE access was to
address N, the READ immediately following would ac­cess data from address N+1. If N=E (where E=32767),
then the counter will ‘wrap around’ to address 0 and
continue to clock out data. After the CAT24WC256
receives its slave address information (with the R/W bit
set to one), it issues an acknowledge, then transmits the
8 bit byte requested. The master device does not send
an acknowledge, but will generate a STOP condition.

Selective/Random Read

Selective/Random READ operations allow the Master
device to select at random any memory location for a
READ operation. The Master device first performs a
‘dummy’ write operation by sending the START condi­tion, slave address and byte addresses of the location it

wishes to read. After CAT24WC256 acknowledges, the
Master device sends the START condition and the slave
address again, this time with the R/W bit set to one. The
CAT24WC256 then responds with its acknowledge and
sends the 8-bit byte requested. The master device does
not send an acknowledge but will generate a STOP
condition.

Sequential Read

The Sequential READ operation can be initiated by
either the Immediate Address READ or Selective READ
operations. After the CAT24WC256 sends the initial 8­bit byte requested, the Master will respond with an
acknowledge which tells the device it requires more
data. The CAT24WC256 will continue to output an 8-bit
byte for each acknowledge sent by the Master. The
operation will terminate when the Master fails to respond
with an acknowledge, thus sending the STOP condition.

The data being transmitted from CAT24WC256 is out­putted sequentially with data from address N followed by
data from address N+1. The READ operation address
counter increments all of the CAT24WC256 address bits
so that the entire memory array can be read during one
operation. If more than E (where E=32767) bytes are
read out, the counter will ‘wrap around’ and continue to
clock out data bytes.

Figure 8. Immediate Address Read Timing

24WC256 F10

24WC128 F10

SCL

SDA 8TH BIT

STOPNO ACKDATA OUT

89

SLAVE

ADDRESS

S

A
C
K

BUS ACTIVITY :

MASTER

SDA LINE

S

T
A
R

T

N
O
A
C
K

DATA

S
T
O
P

P

PreliminaryCAT24WC256

8

Doc. No. 25061-00 6/99 S-1

Figure 9. Selective Read Timing

ORDERING INFORMATION

Notes:
(1) The device used in the above example is a 24WC256KI-1.8TE13 (SOIC, Industrial Temperature, 1.8 Volt to 6 Volt Operating

Voltage, Tape & Reel)

Figure 10. Sequential Read Timing

5020 FHD F12

BUS ACTIVITY:

MASTER

SDA LINE

DATA n+xDATA n

A
C
K

A
C
K

DATA n+1

A
C
K

S
T
O
P

N
O

A
C
K

DATA n+2

A
C
K

P

SLAVE

ADDRESS

24WC256 FIG. 11

24WC256 FIG. 13

*

=Don't Care Bit

24WC128 F11

A15–A

8

SLAVE

ADDRESS

S

A
C
K

A

C

K

A
C
K

BUS ACTIVITY :

MASTER

SDA LINE

S
T

A
R
T

A7–A

0

BYTE ADDRESS SLAVE

ADDRESS

S

A
C
K

N
O
A
C
K

S
T
A

R

T

DATA

P

S
T
O
P

*

Temperature Range

Blank = Commercial (0˚ - 70˚C)
I = Industrial (-40˚ - 85˚C)
A = Automotive (-40˚ - 105˚C)*

* -40˚ to +125˚C is available upon request

Prefix Device # Suffix

K

I

TE13

Product
Number

Tape & Reel

TE13: 2000/Reel

Package

P: PDIP
K: SOIC (EIAJ)

Operating Voltage

Blank: 2.5 to 6.0V

1.8: 1.8 to 6.0V
3: 3.0V to 5.5V

-1.8

24WC256

CAT

Optional
Company ID