SGS Thomson Microelectronics M2732A Datasheet

FA ST ACCESS TIME: 200ns
EXTENDED TEMPERATURE RANGE
SINGLE 5V SUPPLY VOLTAGE
LOW STANDBY CURRE NT: 35mA max
INPUTS and OUTP UT S TT L CO MPATIB LE

DURING REA D a n d PRO GR AM
COM P LETELY STATIC

DESCRIP TION

The M2732A is a 32,768 bit UV erasable and
electrically programmable memory EPROM. It is
organized as 4,0 96 words by 8 bit s. The M2732A
with its single 5V pow er supply an d with an acc ess
time of 200 ns, is ideal suited for applications wher e
fast turn around and pattern experimentation one
important requirements.

The M2732A is honsed in a 24 pin Window Ceramic
Frit-Seal Dual-in-Line pac kage. The transparent lid
allows the user to expose the chip t o ultraviolet light
to erase the bit patt ern. A new pattern can be then
written to the cleric e by following t he programmi ng
procedure.

M2732A

NMOS 32K (4K x 8) UV EPROM

24

1

FDIP24W (F)

Figure 1. Logic Diag ra m

V

CC

12

A0-A11 Q0-Q7

8

E

T able 1. Signal Names

A0 - A11 Address Inputs
Q0 - Q7 Data Outputs
E Chip Enable
GV

PP

V

CC

V

SS

July 1994 1/9

Output Enable / Program Supply
Supply Voltage
Ground

GV

PP

M2732A

V

SS

AI00780B

M2732A

Tab le 2. Absol ute Maxim u m Ratin gs

Symbol Parameter Value Unit

T

A

T

BIAS

T

STG

V

IO

V

CC

V

PP

Note: Except for the rating "Operating T emperature R ange", stresses above those lis ted in the Table "Absolute Maximum Ratings" may cause
permanent damage to the device. These are stress ratings only and opera tion 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 Rati ng conditions for extended periods
may affect device reliabil ity. Refer also to the SGS-THOMSON SURE Program and other relevant quality documents.

Ambient Operating Temperature grade 1

grade 6

Temperature Under Bias grade 1

grade 6
Storage Temperature –65 to 125 °C
Input or Output Voltages –0.6 to 6 V
Supply Voltage –0.6 to 6 V
Program Supply Voltage –0.6 to 22 V

0 to 70

–40 to 85
–10 to 80

–50 to 95

°C

°C

Figure 2. DIP Pin Connecti ons

A7

1
2

A6

3

A5
A4

4
5

A3

6

A2
A1

A0
Q0
Q1
Q2

V

SS

M2732A

7
8
9
10
11
12

24
23
22
21
20
19
18
17
16
15
14
13

AI00781

V

CC

A8
A9
A11
GV
A10
E
Q7
Q6
Q5
Q4
Q3

PP

DEVICE OPER ATION

The six modes of operation for the M2732A are
listed in the Operating Modes Table. A single 5V
power supply is required in the read mode. All
inputs are TTL level except for V

PP.

Read Mode

The M2732A has two control functions, both of
which must be logically satisfied in order to obtai n
data at the outputs. Chip Enable (

E) is the power
control and should be used for device selection.
Output Enable (

G) is the output control and should

be used to gate data to the output pins, inde­pendent of device selection.

Assuming that the addresses are stable, address
access time (t
output (t

ELQV

the falling edge of

) is equal to the delay fr om E to

AVAQ

). Data is available at the outputs after

G, assuming that E has been low
and the addresses have been stable for at least
t

AVQ V-tGLQV

.

Stand by Mod e

The M2732A has a standby mode which reduces
the active power current by 70 %, from 125 mA to
35 mA. The M2732A is placed in the sta ndby mode
by applying a TTL high signal to

E input. When in
standby mode, the outputs are in a high impedance
state, independent of the

GVPP input.

Two Line Output Control

Because M2732A ’s are usually used in larger mem­ory arrays, this product features a 2 line control
function which accommodates the use of multiple
memory connection. The two line control function
allows:

a. the lowest possible memory power dissipation,
b. complete assurance that output bus content i on

will not occur.

To most efficiently use these two control lines, it is
recommended that
primary device selecting function, while

E be decoded and used as the

G should
be made a common connection to all devices in the
array and connected to the

READ line from the

system control bus.
This ensures that all deselected memory devices

are in their low power standby mode and that the
output pins are only active when data is required
from a particular memory device.

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M2732A

Programmin g

When delivered, and after each erasure, all bits of
the M2732A are in the “1" state. Data is introduce d
by selectively programming ”0’s" into the desired
bit locations. Although only “0’s” will be pro­grammed, both “1’s” a nd “0’s” c an be present ed in
the data word. The only way to change a “0" to a
”1" is by ultraviolet light erasure.

The M2732A is in the programming mode when the
GVPP input is at 21V. A 0.1µF capacitor must be
placed across

GVPP and ground to suppress spu­rious voltage transients which may damage the
device. The data to be programmed is applied, 8
bits in parallel, to the data output pins. The levels
required for the address and data inputs are TTL.

When the address and data are stable, a 50ms,
active low, TTL program pulse is applied to the
input. A program pulse must be applied at each
address location to be programmed. Any location
can be programmed at any time - either individually ,
sequentially, or at random. T he program pulse has
a maximum width of 55ms. The M2732A must not
be programmed with a DC signal applied to the
input.

Programming of multiple M2732As in parallel with
the same data can be easily accomplished due to
the simplicity of the programming requirements.
Inputs of the paralleled M2732As may be con­nected together when they are programmed with
the same data. A low level TTL pulse applied to the
E input programs the paralleled 2732As.

Program Inhibit

Programming of multiple M2732As in parallel with
different data is also easily accomplished. Except
for

E, all like inputs (including GVPP) of the parallel

M2732As may be common. A T TL level program

pulse applied to a M2732A’s

E input with GV
21V will program that M2732A. A high level
inhibits the other M2732As from being pro­grammed.

Program Verify

A verify should be performed on the programmed
bits to determine that they were correctly pro­grammed. The verify is carried out with
E at VIL.

ERASURE OPERATION
The erasure characteristics of the M2732A are

such that erasure begins when the cells are ex­posed to light with wavelengths shorter than ap­proximately 4000 Å. It should be noted that sunlight
and certain types of fluorescent lamps have wave­lengths in the 3000-4000 Å range. Research shows

E

that constant exposure to room level fluorescent
lighting could erase a typical M2732A in approxi­mately 3 years, while it would take approximately
1 week to cause erasure when exposed to the
direct sunlight. If the M2732A is to be exposed to
these types of lighting conditions for extended pe-

E

riods of time, it is suggested that opaque labels be
put over the M2732A window to prevent uninten­tional erasure.

The recommended erasure procedure for the
M2732A is exposure to shortwave ultraviolet light
which has a wavelength of 2537 Å. The integrated
dose (i.e. UV intensity x exposure time) for erasure
should be a minimum of 15 W-sec/cm
sure time with this dosage is approximately 15 to
20 minutes using an ultraviolet lamp with 12000
µW/cm

2

power rating. The M2732A should be
placed within 2.5 cm of the lamp tubes during
erasure. Some lamps have a filter on their tubes
which should be removed before erasure.

PP

E input

GVPP and

2

. The era-

at

T ab le 3. Operating Modes

Mode E GV

Read V
Program VIL Pulse V
Verify V
Program Inhibit V
Standby V

Note: X = VIH or VIL.

IL

IL

IH

IH

PP

V

IL

PP

V

IL

V

PP

XVCCHi-Z

V

CC

V

CC

V

CC

V

CC

V

CC

Q0 - Q7

Data Out

Data In

Data Out

Hi-Z

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