SGS Thomson Microelectronics M27C64A Datasheet

64 Kbit (8Kb x 8) UV EPROM and OTP EPROM

5V ± 10% SUPPLY VOLTAGE in READ
OPERATION

FAST A CCES S TIME : 150ns
LOW POWER “CMOS” CONSUMPTION:
– Active Current 30mA
– Standby Current 100µA
PROGRAMMING VOLT AGE: 12.5V ± 0.25V
HIGH SP EED PROGRAMMING

(less than 1 minute)
ELECTRONIC SIGNATURE
– Manufacturer Code: 9Bh
– Device Code: 08h

DESCRIPTION

The M27C64A is a 64Kbit EPROM offered in the
two ranges UV (ultra violet erase) and OTP (one
time programmable). It is ideally suited for micro­processor systems requiring large programs and is
organized as 8,192 by 8 bits.

The FDIP28W (window ceramic frit-seal package)
has transparent lid which allows the user to expose
the chip to ultraviolet light to erase the bit pattern.
A new pattern can then be written to the device by
following the programming procedure.

For applications where the content is programmed
only on time and erasure is not required, the
M27C64A is offered in PLCC32 package.

28

1

FDIP28W (F)

Figure 1. Logic Diagram

V

CC

13

A0-A12

M27C64A

PLCC32 (C)

V

PP

8

Q0-Q7

T ab le 1. Signal Names

A0-A12 Address Inputs
Q0-Q7 Data Outputs
E Chip Enable
G Output Enable
P Program
V

PP

V

CC

V

SS

March 1998 1/12

Program Supply
Supply Voltage
Ground

P

E

G

M27C64A

V

SS

AI00834B

M27C64A

Figure 2A. DIP Pin Connections

V

Warning:

1

PP

2

A7

3
4

A6

5

A5
A4

6
7

A3
A2
A1

A0
Q0
Q1
Q2

V

SS

NC = Not Connected

M27C64A

8
9
10
11
12
13
14

28
27
26
25
24
23
22
21
20
19
18
17
16
15

AI00835

V

CC

PA12
NC
A8
A9
A11
G
A10
E
Q7
Q6
Q5
Q4
Q3

Figure 2B. LCC Pin Connections

PP

CC

DU

32

DU

V

Q3

P

Q4

Warning:

V

A7

A12

1

A6
A5
A4
A3
A2

9

M27C64A
A1
A0

NC

Q0

17

Q1

Q2

SS

V

NC = Not Connected, DU = Don’t Use

NC

25

Q5

A8
A9
A11
NC
G
A10
E
Q7
Q6

AI00836

(1)

T ab le 2. Absolute Maximum Ratings

Symbol Parameter Value Unit

T

A

T

BIAS

T

STG

(2)

V

IO

V

CC

(2)

V

A9

V

PP

Notes:

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

2. Minimum DC voltage on Input or Output is –0.5V with possible undershoot to –2.0V for a period less than 20ns. Maximum DC

3. Depends on range.

Ambient Operating Temperature
Temperature Under Bias –50 to 125 °C
Storage Temperature –65 to 150 °C
Input or Output Voltages (except A9) –2 to 7 V
Supply Voltage –2 to 7 V
A9 Voltage –2 to 13.5 V
Program Supply Voltage –2 to 14 V

may cause permanent damage to the device. These are stress rating s 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 STMicroelectronics SURE Program and other
relevant quality documents.

voltage on Output is V

+0.5V with possible overshoot to VCC +2V for a period less than 20ns.

CC

DEVICE O PERATION

The modes of operation of the M27C64A are listed
in the Operating Modes table. A single power sup­ply is required in the read mode. All inputs are TTL
levels except for V

and 12V on A9 for Electronic

PP

Signature.

(3)

–40 to 125 °C

Read Mode

The M27C64A has two control functions, both of
which must be logically active in order to obtain
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

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M27C64A

be used to gate data to the output pins, inde­pendent of device selection. Assuming that the
addresses are stable, the address access time

) is equal to the delay from E to output (t

(t

AV QV

Data is available at the output after a delay of t

ELQV

GLQV

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

AVQV-tGLQV

.

Standby Mode

The M27C64A has a standby mode which reduces
the active current from 30mA to 100µA. The
M27C64A is placed in the standby mode by apply­ing a CMOS high signal to the

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

G input.

T wo Line Output Control

Because EPROMs 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 contention

will not occur.

For the most efficient use of these two control lines,
E should be decoded and used as the primary
device selecting function, while

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.

System Considerations

The power switching characteristics of Advanced
CMOS EPROMs require careful decoupling of the
devices. The supply current, I

, has three seg-

CC

ments that are of interest to the system designer:
the standby current level, the active c urrent level,
and transient current peaks that are produced by
the falling and rising edges of

E. The magnitude of
the transient current peaks is dependent on the
capacitive and inductive loading of the device at the
output.

The associated transient voltage peaks can be
suppressed by complying with the two line output
control and by properly selected decoupling ca­pacitors. It is recommended that a 0.1µF ceramic
capacitor be used on every device between V
and VSS. This should be a high frequency capacitor
of low inherent inductance and should be placed
as close to the device as possible. I n addition, a

4.7µF bulk electrolytic capacitor should be used
between V

and VSS for every eight devices. T he

CC

bulk capacitor should be located near the power
supply connection point. The purpose of the bulk
capacitor is to overcome the voltage drop caused
by the inductive effects of PCB traces.

CC

T ab le 3. Operating Modes

Mode E G PA9VPPQ0 - Q7

Read V
Output Disable V
Program V
Verify V
Program Inhibit V
Standby V
Electronic Signature V

Note

: X = V

or VIL, VID = 12V ± 0.5V

IH

IL
IL
IL
IL
IH
IH
IL

V

IL

V

IH

V

IH

V

IL

XXXVPPHi-Z
XXXVCCHi-Z

V

IL

V

IH

V

IH

VIL Pulse X V

V

IH

V

IH

XVCCData Out
XVCCHi-Z

XVPPData Out

V

ID

PP

V

CC

T able 4. Electronic Signature

Identifier A0 Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q0 Hex Data

Manufacturer’s Code V
Device Code V

IL

IH

10011011 9Bh
00001000 08h

Data In

Codes

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M27C64A

Programming

When delivered (and after each erasure for UV
EPROM), all bits of the M27C64A are in the "1"
state. Data is introduced by selectively program­ming "0"s into the desired bit locations. Although
only "0"s will be programmed, both "1"s and "0"s
can be present in the dat a word. The only way to
change a "0" to a "1" is by die exposition to ultra­violet light (UV EPROM). The M27C64A is in the
programming mode when V
is at V

and P is pulsed to VIL. The data to be

IL

input is at 12.5V, E

pp

programmed is applied to 8 bits in parallel to the
data output pins. The levels required for the ad­dress and data inputs are TTL. V

is specified to

CC

be 6V ± 0.25V .

High Speed Programming

The high speed programming algorithm, described
in the flowchart, rapidly programs the M27C64A
using an efficient and reliable method, part icularly
suited to the production programming environ­ment. An individual device will take around 1 minute
to program.

Program Inhibit

Programming of multiple M27C64A in parallel with
different data is also easily accomplished. Except

E, all like inputs including G of the parallel

for
M27C64A may be common. A TTL low level pulse
applied to a M27C64A

P input, with E low and V

PP

at 12.5V, will program that M27C64A. A high level

E input inhibits the other M27C64A from being
programmed.

Program Verify

A verify (read) should be performed on the pro­grammed bits to determine that they were correctly
programmed. The verify is accomplished with

G at VIL, P at VIH, VPP at 12.5V and VCC at 6V.

and

Electronic Signature

The Electronic Signature (ES) mode allows the
reading out of a binary code from an EPROM that
will identify its manufacturer and type. This mode
is intended for use by programming equipment to
automatically match the device to be programmed
with its corresponding programming algorithm. The
ES mode is functional in the 25°C ± 5°C ambient
temperature range that is required when program­ming the M27C64A. To activate the ES mode, the
programming equipment must force 1 1.5V to 12.5V
on address line A9 of the M27C64A, with
V

PP=VCC

=5V. Two identifier bytes may then be
sequenced from the device outputs by toggling
address line A0 from V
lines must be held at V

to VIH. All other address

IL

during Electronic Signa-

IL

ture mode.
Byte 0 (A0=V

and byte 1 (A0=V

) represents the manufacturer code

IL

) the device identifier code. For

IH

the STMicroelectronics M27C64A, these two iden­tifier bytes are given in Table 4 and can be read-out
on outputs Q0 to Q7.

E

4/12