1/15

March 2000

M27W401

4 Mbit (512Kb x 8) Low Voltage UV EPROM and OTP EPROM

2.7V to 3.6V LOW VOLTAGE in READ
OPERATION

ACCESS TIME:

70ns at V

= 3.0V to 3.6V

80ns at V

= 2.7V to 3.6V

PIN COMPATIBLE with M27C4001

LOW POWER CONSUMPTION:

A max Standby Current

15mA max Active Current at 5MHz

PROGRAMMING TIME 100

s/byte

HIGH RELIABILITY CMOS TECHNOLOGY

2,000V ESD Protection

200mA Latchup Protection Immunity

ELECTRONIC SIGNATURE

Manufacturer Code: 20h

Device Code: 41h

DESCRIPTION
The M27W401 is a low voltage 4 Mbit EPROM of-
fered in the two ranges UV (ultra violet erase) and
OTP (one time programmable). It is ideally suited
for microprocessor systems requiring large data or
program storage and is organised as 524,288 by 8
bits.
The M27W401 operates in the read mode with a
supply voltage as low as 2.7V at 40 to 85

C tem-

perature range. The decrease in operating power
allows either a reduction of the size of the battery
or an increase in the time between battery re-
charges.
The FDIP32W (window ceramic frit-seal package)
has a transparent lid which allows the user to ex-
pose the chip to ultraviolet light to erase the bit pat-
tern. A new pattern can then be written to the
device by following the programming procedure.
For application where the content is programmed
only one time and erasure is not required, the
M27W401 is offered in PDIP32, PLCC32 and
TSOP32 (8 x 20 mm) packages.

Figure 1. Logic Diagram

AI01590

A0-A18

Q0-Q7

VPP

VCC

M27W401

VSS

FDIP32W (F)

PLCC32 (K)

TSOP32 (N)

8 x 20 mm

PDIP32 (B)

M27W401

2/15

Figure 2B. LCC Connections

AI01591

A17

A10

A18

A16

A11

A13

A12

M27W401

A15

A14

Figure 2A. DIP Connections

A13

A10

A14

A11

VSS

A17

A18

A16

A12

VPP

VCC

A15

AI02676

M27W401

Table 1. Signal Names

A0-A18

Address Inputs

Q0-Q7

Data Outputs

Chip Enable

Output Enable

Program Supply

Supply Voltage

Ground

Figure 2C. TSOP Connections

A13

A10

A14

A11

A17

A18

A16

A12

VPP

VCC

A15

AI01592

M27W401

(Normal)

VSS

3/15

M27W401

Table 2. Absolute Maximum Ratings

(1)

Note: 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 condi-
tions for extended periods may affect device reliability. Refer also to the STMicroelectronics SURE Program and other relevant qual-
ity documents.

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

voltage on Output is V

+0.5V with possible overshoot to V

+2V for a period less than 20ns.

3. Depends on range.

Table 3. Operating Modes

Note: X = V

or V

, V

= 12V

0.5V.

Table 4. Electronic Signature

Symbol

Parameter

Value

Unit

Ambient Operating Temperature

(3)

40 to 85

BIAS

Temperature Under Bias

50 to 125

STG

Storage Temperature

65 to 150

(2)

Input or Output Voltage (except A9)

2 to 7

Supply Voltage

2 to 7

(2)

A9 Voltage

2 to 13.5

Program Supply Voltage

2 to 14

Mode

Q7-Q0

Read

or V

Data Out

Output Disable

or V

Hi-Z

Program

Pulse

Data In

Verify

Data Out

Program Inhibit

Hi-Z

Standby

or V

Hi-Z

Electronic Signature

Codes

Identifier

Hex Data

Manufacturer's Code

20h

Device Code

41h

M27W401

4/15

DEVICE OPERATION
The operating modes of the M27W401 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

Signature.
Read Mode
The M27W401 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
be used to gate data to the output pins, indepen-
dent of device selection. Assuming that the ad-
dresses are stable, the address access time

AVQV

) is equal to the delay from E to output

ELQV

). Data is available at the output after a delay

of t

GLQV

from the falling edge of G, assuming that

E has been low and the addresses have been sta-
ble for at least t

AVQV

-t

GLQV

Standby Mode
The M27W401 has a standby mode which reduc-
es the supply current from 15mA to 15

A with low

voltage operation V

3.6V, see Read Mode DC

Characteristics table for details. The M27W401 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.

Table 5. AC Measurement Conditions

High Speed

Standard

Input Rise and Fall Times

10ns

20ns

Input Pulse Voltages

0 to 3V

0.4V to 2.4V

Input and Output Timing Ref. Voltages

1.5V

0.8V and 2V

Figure 3. AC Testing Input Output Waveform

AI01822

High Speed

1.5V

2.4V

Standard

0.4V

2.0V

0.8V

Figure 4. AC Testing Load Circuit

AI01823B

1.3V

OUT

CL = 30pF for High Speed
CL = 100pF for Standard
CL includes JIG capacitance

3.3k

1N914

DEVICE

UNDER

TEST

Table 6. Capacitance

(1)

= 25

C, f = 1 MHz)

Note: 1. Sampled only, not 100% tested.

Symbol

Parameter

Test Condit ion

Min

Max

Unit

Input Capacitance

= 0V

OUT

Output Capacitance

OUT

= 0V

5/15

M27W401

Table 7. Read Mode DC Characteristics

(1)

= 40 to 85

C; V

= 2.7V to 3.6V; V

= V

)

Note: 1. V

must be applied simultaneously with or before V

and removed simultaneously or after V

2. Maximum DC voltage on Output is V

+0.5V.

Symbol

Parameter

Test Condition

Min

Max

Unit

Input Leakage Current

Output Leakage Current

OUT

Supply Current

E = V

, G = V

, I

OUT

= 0mA,

f = 5MHz, V

3.6V

CC1

Supply Current (Standby) TTL

E = V

CC2

Supply Current (Standby) CMOS

E > V

0.2V, V

3.6V

Program Current

= V

Input Low Voltage

0.6

0.2 V

(2)

Input High Voltage

0.7 V

+ 0.5

Output Low Voltage

= 2.1mA

0.4

Output High Voltage TTL

= 400

2.4

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

, has three seg-

ments that are of interest to the system designer:
the standby current level, the active current 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 ca-
pacitors. It is recommended that a 0.1

F ceramic

capacitor be used on every device between V

and V

. This should be a high frequency capaci-

tor of low inherent inductance and should be
placed as close to the device as possible. In addi-
tion, a 4.7

F bulk electrolytic capacitor should be

used between V

and V

for every eight devic-

es. The 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.

Two Line Output Control
Because EPROMs are usually used in larger
memory arrays, this product features a 2 line con-
trol function which accommodates the use of mul-
tiple 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 prima-
ry 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 deselect-
ed 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.

M27W401

6/15

Figure 5. Read Mode AC Waveforms

AI00724B

tAXQX

tEHQZ

A0-A18

Q0-Q7

tAVQV

tGHQZ

tGLQV

tELQV

VALID

Hi-Z

VALID

Table 8. Read Mode AC Characteristics

(1)

= 40 to 85

C; V

= 2.7V to 3.6V; V

= V

)

Note: 1. V

must be applied simultaneously with or before V

and removed simultaneously or after V

2. Sampled only, not 100% tested.
3. Speed obtained with High Speed AC measurement conditions.

Symbol

Alt

Parameter

Test

Condition

M27W401

Unit

-80

(3)

-100

(-120/-150/-200)

= 3.0V to 3.6V V

= 2.7V to 3.6V V

= 2.7V to 3.6V

Min

Max

Min

Max

Min

Max

AVQV

ACC

Address Valid to
Output Valid

E = V

G = V

100

ELQV

Chip Enable Low to
Output Valid

G = V

100

GLQV

Output Enable Low
to Output Valid

E = V

EHQZ

(2)

Chip Enable High
to Output Hi-Z

G = V

GHQZ

(2)

Output Enable High
to Output Hi-Z

E = V

AXQX

Address Transition
to Output Transition

E = V

G = V

7/15

M27W401

Table 9. Programming Mode DC Characteristics

(1)

= 25

C; V

= 6.25V

0.25V; V

= 12.75V

0.25V)

Note: 1. V

must be applied simultaneously with or before V

and removed simultaneously or after V

Table 10. Programming Mode AC Characteristics

(1)

= 25

C; V

= 6.25V

0.25V; V

= 12.75V

0.25V)

Note: 1. V

must be applied simultaneously with or before V

and removed simultaneously or after V

2. Sampled only, not 100% tested.

Symbol

Parameter

Test Condition

Min

Max

Unit

Input Leakage Current

Supply Current

Program Current

E = V

Input Low Voltage

0.3

0.8

Input High Voltage

+ 0.5

Output Low Voltage

= 2.1mA

0.4

Output High Voltage TTL

= 400

2.4

A9 Voltage

11.5

12.5

Symbol

Alt

Parameter

Test Condi tion

Min

Max

Unit

AVEL

Address Valid to Chip Enable Low

QVEL

Input Valid to Chip Enable Low

VPHEL

VPS

High to Chip Enable Low

VCHEL

VCS

High to Chip Enable Low

ELEH

Chip Enable Program Pulse Width

105

EHQX

Chip Enable High to Input Transition

QXGL

OES

Input Transition to Output Enable Low

GLQV

Output Enable Low to Output Valid

100

GHQZ

DFP

Output Enable High to Output Hi-Z

130

GHAX

Output Enable High to Address
Transition

ming '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 data word. The only way to
change a `0' to a `1' is by die exposure to ultraviolet
light (UV EPROM). The M27W401 is in the pro-
gramming mode when V

input is at 12.75V, G is

at V

and E is pulsed to V

. The data to be pro-

grammed 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 be

6.25V

0.25V

Programming
The M27W401 has been designed to be fully com-
patible with the M27C4001 and has the same elec-
tronic signature. As a result the M27W401 can be
programmed as the M27C4001 on the same pro-
gramming equipment applying 12.75V on V

and

6.25V on V

by the use of the same PRESTO II

algorithm.
When delivered (and after each `1's erasure for UV
EPROM), all bits of the M27W401 are in the '1'
state. Data is introduced by selectively program-

M27W401

8/15

Figure 7. Programming Flowchart

AI00760C

n = 0

Last

Addr

VERIFY

E = 100

s Pulse

++n

= 25

++ Addr

VCC = 6.25V, VPP = 12.75V

FAIL

CHECK ALL BYTES

1st: VCC = 5V

2nd: VCC = 2.7V

YES

PRESTO II Programming Algorithm
PRESTO II Programming Algorithm allows the
whole array to be programmed with a guaranteed
margin, in a typical time of 52.5 seconds. Pro-
gramming with PRESTO II consists of applying a
sequence of 100

s program pulses to each byte

until a correct verify occurs (see Figure 7). During
programming and verify operation, a MARGIN
MODE circuit is automatically activated in order to
guarantee that each cell is programmed with
enough margin. No overprogram pulse is applied
since the verify in MARGIN MODE at VCC much
higher than 3.6V, provides the necessary margin
to each programmed cell.
Program Inhibit
Programming of multiple M27W401s in parallel
with different data is also easily accomplished. Ex-
cept for E, all like inputs including G of the parallel
M27W401 may be common. A TTL low level pulse
applied to a M27W401's E input, with V

12.75V, will program that M27W401. A high level
E input inhibits the other M27W401s from being
programmed.
Program Verify
A verify (read) should be performed on the pro-
grammed bits to determine that they were correct-
ly programmed. The verify is accomplished with G
at V

, E at V

, V

at 12.75V and V

at 6.25V.

Figure 6. Programming and Verify Modes AC Waveforms

tAVPL

VALID

AI00725

A0-A18

Q0-Q7

VPP

VCC

DATA IN

DATA OUT

tQVEL

tVPHEL

tVCHEL

tEHQX

tELEH

tGLQV

tQXGL

tGHQZ

tGHAX

PROGRAM

VERIFY

9/15

M27W401

ERASURE OPERATION (applies to UV EPROM)
The erasure characteristics of the M27W401 are
such that erasure begins when the cells are ex-
posed to light with wavelengths shorter than ap-
proximately 4000 Å. It should be noted that
sunlight and some type of fluorescent lamps have
wavelengths in the 3000-4000 Å range. Data
shows that constant exposure to room level fluo-
rescent lighting could erase a typical M27W401 in
about 3 years, while it would take approximately 1
week to cause erasure when exposed to direct
sunlight. If the M27W401 is to be exposed to these
types of lighting conditions for extended periods of
time, it is suggested that opaque labels be put over
the M27W401 window to prevent unintentional
erasure. The recommended erasure procedure for
the M27W401 is exposure to short wave ultraviolet
light which has wavelength of 2537 Å. The inte-
grated dose (i.e. UV intensity x exposure time) for
erasure should be a minimum of 15 W-sec/cm

The erasure time with this dosage is approximate-
ly 15 to 20 minutes using an ultraviolet lamp with
12000

W/cm

power rating. The M27W401

should be placed within 2.5 cm (1 inch) of the lamp
tubes during the erasure. Some lamps have a filter
on their tubes which should be removed before
erasure.

On-Board Programming
The M27W401 can be directly programmed in the
application circuit. See the relevant Application
Note AN620.
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 am-

bient temperature range that is required when pro-
gramming the M27W401. To activate the ES
mode, the programming equipment must force
11.5V to 12.5V on address line A9 of the
M27W401 with V

= V

= 5V. Two identifier

bytes may then be sequenced from the device out-
puts by toggling address line A0 from V

to V

. All

other address lines must be held at V

during

Electronic Signature mode. Byte 0 (A0 = V

) rep-

resents the manufacturer code and byte 1
(A0 = V

) the device identifier code. For the

STMicroelectronics M27W401, these two identifier
bytes are given in Table 4 and can be read-out on
outputs Q7 to Q0. Note that the M27W401 and
M27C4001 have the same identifier bytes.

M27W401

10/15

Table 11. Ordering Information Scheme

Note: 1. High Speed, see AC Characteristics section for further information.

2. This speed also guarantees 70ns access time at V

= 3.0V to 3.6V.

3. These speeds are replaced by the 100ns.
4. Packages option available on request. Please contact STMicroelectronics local Sales Office.

For a list of available options (Speed, Package, etc...) or for further information on any aspect of this de-
vice, please contact the STMicroelectronics Sales Office nearest to you.

Example:

M27W401

-80

Device Type
M27

Supp ly Voltage
W = 2.7V to 3.6V

Device Function
401 = 4 Mbit (512Kb x 8)

Speed

-80

(1,2)

= 80 ns

-100 = 100 ns

Not For New Design

(3)

-120 = 120 ns
-150 = 150 ns
-200 = 200 ns

Package

F = FDIP32W

(4)

B = PDIP32
K = PLCC32

N = TSOP32: 8 x 20 mm

(4)

Temperature Range
6 = 40 to 85

Optio ns
TR = Tape & Reel Packing

Table 12. Revision History

Date

Revision Details

July 1999

First Issue

03/10/00

FDIP42W Package Dimension, L Max added (Table 13)
TSOP32 Package Dimension changed (Table 16)
0 to 70

C Temperature Range deleted

11/15

M27W401

Table 13. FDIP32W - 32 pin Ceramic Frit-seal DIP with window, Package Mechanical Data

Symb

inches

Typ

Min

Max

Typ

Min

Max

5.72

0.225

0.51

1.40

0.020

0.055

3.91

4.57

0.154

0.180

3.89

4.50

0.153

0.177

0.41

0.56

0.016

0.022

1.45

0.057

0.23

0.30

0.009

0.012

41.73

42.04

1.643

1.655

38.10

1.500

15.24

0.600

13.06

13.36

0.514

0.526

2.54

0.100

14.99

0.590

16.18

18.03

0.637

0.710

3.18

4.10

0.125

0.161

1.52

2.49

0.060

0.098

7.11

0.280

Figure 8. FDIP32W - 32 pin Ceramic Frit-seal DIP with window, Package Outline

Drawing is not to scale.

FDIPW-a

M27W401

12/15

Table 14. PDIP32 - 32 lead Plastic DIP, 600 mils width, Package Mechanical Data

Symb

inches

Typ

Min

Max

Typ

Min

Max

5.08

0.200

0.38

0.015

3.56

4.06

0.140

0.160

0.38

0.51

0.015

0.020

1.52

0.060

0.20

0.30

0.008

0.012

41.78

42.04

1.645

1.655

38.10

1.500

15.24

0.600

13.59

13.84

0.535

0.545

2.54

0.100

15.24

0.600

15.24

17.78

0.600

0.700

3.18

3.43

0.125

0.135

1.78

2.03

0.070

0.080

Figure 9. PDIP32 - 32 lead Plastic DIP, 600 mils width, Package Outline

Drawing is not to scale.

PDIP

13/15

M27W401

Table 15. PLCC32 - 32 lead Plastic Leaded Chip Carrier, Package Mechanical Data

Symb

inches

Typ

Min

Max

Typ

Min

Max

2.54

3.56

0.100

0.140

1.52

2.41

0.060

0.095

0.38

0.015

0.33

0.53

0.013

0.021

0.66

0.81

0.026

0.032

12.32

12.57

0.485

0.495

11.35

11.56

0.447

0.455

9.91

10.92

0.390

0.430

14.86

15.11

0.585

0.595

13.89

14.10

0.547

0.555

12.45

13.46

0.490

0.530

1.27

0.050

0.00

0.25

0.000

0.010

0.89

0.035

0.10

0.004

Figure 10. PLCC32 - 32 lead Plastic Leaded Chip Carrier, Package Outline

Drawing is not to scale.

PLCC

E1 E

1 N

D2/E2

0.51 (.020)

1.14 (.045)

M27W401

14/15

Table 16. TSOP32 - 32 lead Plastic Thin Small Outline, 8 x 20mm, Package Mechanical Data

Symbol

inch

Typ

Min

Max

Typ

Min

Max

1.200

0.0472

0.050

0.150

0.0020

0.0059

0.950

1.050

0.0374

0.0413

0.150

0.270

0.0059

0.0106

0.100

0.210

0.0039

0.0083

19.800

20.200

0.7795

0.7953

18.300

18.500

0.7205

0.7283

0.500

0.0197

7.900

8.100

0.3110

0.3189

0.500

0.700

0.0197

0.0276

0.100

0.0039

Figure 11. TSOP32 - 32 lead Plastic Thin Small Outline, 8 x 20mm, Package Outline

Drawing is not to scale.

TSOP-a

N/2

DIE

15/15

M27W401

Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences
of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted
by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject
to change without notice. This publication supersedes and replaces all information previously supplied. STMi croelectronics products are not
authorized for use as critical components in lif e support devices or systems without express written approval of STMicroelectronics.

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