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Contact Memory Card Chip M4428 8K Bits
M4428 is a memory card chip. It uses 0.6um CMOS EEPROM process, has 1K X 8 Bits EEPROM with write protect function and programmable security code. With its contact configuration in accordance to ISO standard 7816 (synchronous transmission), M4428 can be widely used in different types of IC memory cards.
Specifications

Absolute Maximum Ratings

Parameters

Symbol

Limit Values

Unit

min.

typ.

max.

Supply voltage

Vcc

-0.3


6

V

Input voltage

Vi

-0.3


6

V

Storage temperature

Tsto

-40


125

Power dissipation

Ptot



60

mW


DC Characteristics

Parameters

Symbol

Limit Values

Unit

min.

typ.

max.

Supply voltage

Vcc

2.7

5

5.5

V

Supply current

Icc


3

10

mA

H input voltage (I/O,CLK,RST)

Vih

3.5


Vcc

V

L input voltage (I/O,CLK,RST)

Vil

0


0.8

V

H input current (I/O,CLK,RST)

Ih


3.9

10

uA

L output current(Vl=0.4V,open drain)

Iol

0.5



mA

H leakage current (Vl=Vcc,open drain)

Ioh



10

uA

Input capacitance

Ci



10

pF

Clock frequency

f


20


KHz

Test pin

T

Open or on Vss


AC Characteristics

Parameters

Symbol

Limit Values

Unit

min.

typ.

max.

Reset time

tRE

9



us

CLK (count, H level)

tH

10



us

CLK (count, L level)

tL

10



us

Write time

tW

5



ms

Erase time

tE

5



ms

Setup time (D/CLK)

td1

4



us

Setup time (CLK/RST)

td3

4



us

Setup time (RST/CLK)

td4

4



us

Hold time (D/CLK)

td5

4



us

Delay time (CLK/D)

td2

6



us

Rise time (I/O,CLK,RST)

tR



1

us

Fall time (I/O,CLK,RST)

tF



1

us


Characteristics

This chip contains an EEPROM organized 1024 x 8 bit offering the possibility of programmable write protection for each byte.

All the memory, except for the PSC, can always be read.

All the memory is writable/erasable before the protect bit is enabled. After setting the protect bit, the memory is read only.

The (write) protect bit is only one time programmable and can not be erased.

This chip has a PSC verification logic. After 8 successive incorrect entries the error counter will block any subsequent attempt at PSC verification and hence any possibility to write and erase.


Video