The memory is accessed by a set of instructions

which includes Read a byte/word, Write a

byte/word, Erase a byte/word, Erase All and Write

All. A Read instruction loads the address of the first

byte/word to be read into an internal address

pointer. The data contained at this address is then

clocked out serially. The address pointer is auto-

matically incremented after the data is output and,

if the Chip Select input (S) is held High, the

ST93C56 can output a sequential stream of data

bytes/words. In this way, the memory can be read

as a data stream from 8 to 2048 bits long, or

continuously as the address counter automatically

rolls over to ’00’ when the highest address is

reached. Programming is internally self-timed (the

external clock signal on C input may be discon-

nected or left running after the start of a Write cycle)

and does not require an erase cycle prior to the

Write instruction. The Write instruction writes 8 or

16 bits at one time into one of the 256 bytes or 128

words. After the start of the programming cycle, a

Busy/Ready signal is available on the Data output

(Q) when Chip Select (S) is driven High.

The design of the ST93C56 and the High Endur-

ance CMOS technologyused for its fabrication give

an Erase/Write cycle Endurance of 1,000,000 cy-

cles and a data retention of 40 years.

The DU (Don’t Use) pin does not affect the function

of the memory and it is reserved for use by SGS-

THOMSON during test sequences.The pin may be

mended for the lowest standby power consump-

tion.

VSS

Q

ORG

DU

C

SVCC

D

AI00882C

ST93C56

ST93C57

1

2

3

4

8

7

6

5

Figure 2A. DIP Pin Connections

1

VSS

Q

ORG

DU

C

SVCC

D

AI00883D

ST93C56

ST93C57

2

3

4

8

7

6

5

Figure 2B. SO Pin Connections

DESCRIPTION (cont’d)

Warning: DU = Don’t Use

Warning: DU = Don’t Use

Symbol

Parameter

Value

Unit

Ambient Operating Temperature

–40 to 125

°C

Storage Temperature

–65 to 150

°C

Lead Temperature, Soldering

(SO8 package)

(PSDIP8 package)

40 sec

10 sec

215

260

°C

V

Supply Voltage

–0.3 to 6.5

V

Electrostatic Discharge Voltage (Human Body model)

(2)

4000

V

Electrostatic Discharge Voltage (Machine model)

(3)

500

V

Notes: 1. Except for the rating ”Operating Temperature Range”, stresses above those listed in the Table ”Absolute Maximum Ratings”

may cause permanent damage to the device. These are stress ratings only and operation of the device at these or any other

conditions above those indicated in the Operating sections of this specification is not implied. Exposure to Absolute Maximum

Rating conditions for extended periods may affect device reliability. Refer also to the SGS-THOMSON SURE Program and other

relevant quality documents.

2. MIL-STD-883C, 3015.7 (100pF, 1500

Ω).

3. EIAJ IC-121 (Condition C) (200pF, 0

Ω).

Table 2. Absolute Maximum Ratings

(1)

2/13

ST93C56/56C, ST93C57C