The M27W402 is a low voltage 4 Mbit EPROM offered in the two range UV (Ultra Violet Erase) and
OTP (one time programmable). It is ideally suited
for microprocessorsystems requiringlarge data or
program storage and is organised as 262,144 by
16 bits.
The M27W402 operates in the read mode with a
supply voltageas low as2.7V at –40 to 85°C temperature range. The decrease in operating power
allows either a reduction of the size of the battery
or an increase in the time between battery recharges.
The FDIP40W (window ceramic frit-seal package)
has a transparent lids which allow the user to expose thechip 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 wherethe content is programmed
only one time and erasure is not required, the
M27W402 is offered in PDIP40, PLCC44 and
TSOP40 (10 x 20 mm) packages.
A5
A4
A3
A2
A1
A0
G
DQ0
DQ1
DQ2
DQ3
DQ4
DQ5
DQ6
DQ7
V
SS
Table 1. Signal Names
A0-A17Address Inputs
Q0-Q15Data Outputs
EChip Enable
GOutput Enable
V
PP
V
CC
V
SS
NCNot Connected Internally
Program Supply
Supply Voltage
Ground
2/15
Page 3
M27W402
Table 2. Absolute Maximum Ratings
(1)
SymbolParameterValueUnit
T
A
T
BIAS
T
STG
(2)
V
IO
V
CC
(2)
V
A9
V
PP
Note: 1. Except for the rating ”Operating Temperature Range”, stresses above those listed in the Table ”Absolute MaximumRatings” may
cause permanent damage to the device. These are stress ratings onlyand operation ofthe device at these or any other conditions
above those indicated in the Operating sections of this specification is not implied. Exposure toAbsolute Maximum Rating conditions for extended periods may affect device reliability. Refer also to the STMicroelectronics SUREProgram and otherrelevant quality 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
3. Depends on range.
Ambient Operating Temperature
Temperature Under Bias–50 to 125°C
Storage Temperature–65 to 150°C
Input or Output Voltage (except A9)–2 to 7V
Supply Voltage–2 to 7V
A9 Voltage–2 to 13.5V
Program Supply Voltage–2 to 14V
+0.5V with possible overshoot to VCC+2V for a period less than 20ns.
CC
(3)
–40 to 85°C
Table 3. Operating Modes
ModeEGA9
Read
Output DisableV
Program
V
VerifyV
Program Inhibit
Standby
Electronic Signature
Note: X = VIHor VIL,VID= 12V ± 0.5V.
V
IL
IL
PulseV
IL
IH
V
IH
V
IH
V
IL
V
IL
V
IH
IH
V
IL
V
IH
X
XV
X
XVPPData Out
X
XX
V
IL
V
ID
V
PP
V
or V
CC
SS
or V
CC
SS
V
PP
V
PP
V
or V
CC
SS
V
CC
Q15-Q0
Data Out
Hi-Z
Data In
Hi-Z
Hi-Z
Codes
Table 4. Electronic Signature
IdentifierA0Q7Q6Q5Q4Q3Q2Q1Q0Hex Data
Manufacturer’s Code
Device Code
Note: Outputs Q15-Q8 are set to ’0’.
V
IL
V
IH
00100000 20h
01000100 44h
3/15
Page 4
M27W402
Table 5. AC Measurement Conditions
High SpeedStandard
Input Rise and Fall Times≤ 10ns≤ 20ns
Input Pulse Voltages0 to 3V0.4V to 2.4V
Input and Output Timing Ref. Voltages1.5V0.8V and 2V
Figure 3. AC Testing Input Output Waveform
High Speed
3V
1.5V
0V
Standard
2.4V
0.4V
Table 6. Capacitance
SymbolParameterTest ConditionMinMaxUnit
C
IN
C
OUT
Note: Sampled only, not 100% tested.
Input Capacitance
Output CapacitanceV
(1)
(TA=25°C, f = 1 MHz)
2.0V
0.8V
AI01822
Figure 4. AC Testing Load Circuit
1.3V
1N914
3.3kΩ
DEVICE
UNDER
TEST
C
L
CL= 30pF for HighSpeed
CL= 100pF for Standard
CLincludes JIG capacitance
V
=0V
IN
=0V12pF
OUT
6pF
OUT
AI01823B
DEVICE OPERATION
The operation modes of theM27W402 are listed in
the Operating Modes table. A single power supply
is required in the read mode. All inputs are TTL
levels exceptfor VPPand 12Von A9 for Electronic
Signature.
Read Mode
The M27W402 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 outputcontrol and should
be used to gate data to the output pins, independent of device selection. Assuming that the ad-
4/15
dresses are stable, the address access time
(t
) is equal to the delay from E to output
AVQV
(t
). Data is availableatthe outputaftera delay
ELQV
of t
from the falling edge of G, assuming that
GLQV
E has been lowand the addresses havebeen stable for at least t
AVQV-tGLQV
.
Standby Mode
The M27W402 has a standby mode which reduces the supply current from 15mA to 15µAwith low
voltage operation VCC≤ 3.6V, see Read ModeDC
Characteristics table for details. The M27W402 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.
Page 5
M27W402
Table 7. Read Mode DC Characteristics
(1)
(TA= –40to 85°C; VCC= 2.7V to 3.6V; VPP=VCC)
SymbolParameterTest ConditionMinMaxUnit
I
I
I
CC
I
CC1
I
CC2
I
V
V
IH
V
V
Note: 1. VCCmust be applied simultaneously with or before VPPand removed simultaneously or after VPP.
Input Leakage Current
LI
Output Leakage Current
LO
Supply Current
Supply Current (Standby) TTL
Supply Current (Standby) CMOS
Program Current
PP
Input Low Voltage–0.6
IL
(2)
Input High Voltage
Output Low Voltage
OL
Output High Voltage TTL
OH
2. Maximum DC voltage on Output is V
CC
+0.5V.
I
OUT
0V ≤ V
0V ≤ V
E=V
E>V
I
≤ V
IN
CC
≤ V
OUT
CC
,G=VIL,
IL
= 0mA, f = 5MHz,
≤ 3.6V
V
CC
E=V
IH
– 0.2V,
CC
V
≤ 3.6V
CC
V
PP=VCC
I
= 2.1mA
OL
= –400µA
OH
±10µA
±10µA
15mA
1mA
15µA
10µA
0.2 V
CC
0.7 V
CCVCC
2.4V
+ 0.5
0.4V
V
V
Two Line Output Control
Because EPROMs are usually used in larger
memory arrays, the product features a 2 line control function whichaccommodates 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, Eshould be decodedand usedas 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 controlbus. 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 requirecareful decoupling of the
devices. The supply current, ICC, has three segments 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 fallingand rising edges of E. Themagnitude of
the transient current peaks is dependent on the
output capacitive and inductive loading of the device. The associated transient voltage peaks can
be suppressed by complying withthe two line output control and by properly selected decoupling
capacitors.It isrecommended that a 0.1µF ceramic capacitor be used on everydevice between V
CC
and VSS. This should be a high frequency capacitor of low inherent inductance and should be
placed as close to the device as possible. In addition, a 4.7µF bulk electrolytic capacitor should be
used between VCCand VSSfor every eight devices. The bulk capacitor should be located near the
power supply connection point.Thepurpose of the
bulk capacitor is to overcome the voltage drop
caused bythe inductive effects of PCB traces.
5/15
Page 6
M27W402
Table 8. Read Mode AC Characteristics
(1)
(TA= –40to 85°C; VCC= 2.7V to 3.6V; VPP=VCC)
M27W402
(3)
SymbolAltParameter
Test
Condition
VCC= 3.0V to 3.6V VCC= 2.7V to 3.6V VCC= 2.7V to 3.6V
MinMaxMinMaxMinMax
E=V
G=V
G=V
E=V
G=V
E=V
E=V
G=V
,
IL
IL
IL
IL
IL
IL
,
IL
IL
050060070ns
050060070ns
000ns
t
AVQV
t
ELQV
t
GLQV
(2)
t
EHQZ
(2)
t
GHQZ
t
AXQX
Note: 1. VCCmust be applied simultaneously with or before VPPand removed simultaneously or after VPP.
2. Sampled only, not 100% tested.
3. Speed obtained with High Speed AC measurement conditions.
VPPHigh to Chip Enable Low
VCCHigh to Chip Enable Low
Chip Enable Program Pulse Width95105µs
PW
Chip Enable High to Input Transition2µs
DH
2µs
2µs
Input Transition to Output Enable Low2µs
Output Enable Low to Output Valid100ns
OE
V
t
GHQZ
t
GHAX
Note: 1. VCCmust be applied simultaneously with or before VPPand removed simultaneously or after VPP.
2. Sampled only, not 100% tested.
t
Programming
The M27W402 hasbeen designed to be fully compatible with the M27C4002and hasthe same electronic signature. As a result the M27W402 can be
programmed as the M27C4002 on the same programming equipmentapplying 12.75V onVPPand
6.25V on VCCby the use of the same PRESTO II
algorithm. When delivered (andafter each ‘1’s erasure for UV EPROM), all bits of the M27W402 are
in the ’1’ state. Data is introduced by selectively
Output Enable High to Output Hi-Z0130ns
DFP
Output Enable High to Address
t
AH
Transition
though only ’0’s will be programmed, both ’1’s and
’0’scan be present in the dataword. The only way
tochange a ‘0’ toa ‘1’ bydie exposureto ultraviolet
light (UV EPROM). The M27W402 is in the programming modewhenVPPinput is at 12.75V, G is
at VIHand E is pulsed to VIL. The data to be programmedis applied to16 bitsin parallelto thedata
output pins. The levels required for the address
and data inputs are TTL. VCCis specified to be
6.25V ± 0.25V.
programming ’0’s into the desired bit locations. Al-
0ns
7/15
Page 8
M27W402
Figure 6. Programming and Verify Modes AC Waveforms
A0-A17
tAVEL
Q0-Q15
V
PP
V
CC
E
G
DATA IN
tQVEL
tVPHEL
tVCHEL
tELEH
Figure 7. Programming Flowchart
VCC= 6.25V, VPP= 12.75V
n=0
E = 100µs Pulse
NO
NO
VERIFY
YES
Last
NO
Addr
YES
CHECK ALL WORDS
1st: VCC=5V
2nd: VCC= 2.7V
++ Addr
YES
++n
=25
FAIL
VALID
DATA OUT
tEHQX
tGLQV
tQXGL
PROGRAMVERIFY
PRESTO II Programming Algorithm
PRESTO II Programming Algorithm allows the
whole array to be programmed with a guaranteed
margin, in a typical time of 26.5 seconds. Programming with PRESTO II consists of applying a
sequence of 100µs program pulses to each byte
until a correct verify occurs (see Figure 7).During
programming and verify operation, a MARGIN
MODE circuitis automatically activatedin order to
guarantee that each cell is programmed with
enough margin. No overprogram pulse is applied
since the verify in MARGIN MODE at VCCmuch
higher than 3.6V, provides necessary margin to
each programmedcell.
Program Inhibit
Programming of multiple M27W402s in parallel
with different datais also easilyaccomplished. Except for E, all likeinputs including G of the parallel
M27W402 may becommon. ATTLlow level pulse
applied to a M27W402’s E input, with VPPat
12.75V, will program that M27W402. A high level
E input inhibits the other M27W402s from being
programmed.
Program Verify
AI00726D
A verify (read) should be performed on the programmed bitsto determine that theywere correctly programmed. The verify is accomplished with G
at VIL, E at VIH,VPPat 12.75V and VCCat 6.25V.
tGHQZ
tGHAX
AI00730
8/15
Page 9
M27W402
On-Board Programming
The M27W402 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 froman EPROM that
will identify its manufacturer and type. This mode
is intended for use by programming equipment to
automatically matchthe deviceto beprogrammed
with its corresponding programming algorithm.
The ES mode is functional in the 25°C ± 5°C ambient temperaturerange that is required when programming the M27W402. To activate the ES
mode, the programming equipment must force
11.5V to 12.5V on address line A9 of the
M27W402 with VPP=VCC= 5V. Two identifier
bytes maythen besequenced fromthe deviceoutputs bytoggling address lineA0from VILtoVIH. All
other address lines must be held at VILduring
Electronic Signature mode. Byte 0 (A0 = VIL) represents the manufacturer code and byte 1
(A0 = VIH) the device identifier code. For the
STMicroelectronics M27W402,these two identifier
bytes are given in Table 4 and can be read-out on
outputs Q7 to Q0.
Note that the M27W402 and M27C4002 have the
same identifier bytes.
ERASUREOPERATION (applies to UV EPROM)
The erasure characteristics of the M27W402 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 some type of fluorescent lamps have
wavelengths in the 3000-4000 Å range. Research
shows that constant exposure to room level fluorescent lighting coulderase a typicalM27W402 in
about 3years, while it would takeapproximately 1
week to cause erasure when exposed to direct
sunlight. If the M27W402 isto be exposed tothese
types of lighting conditions forextended periods of
time, it is suggested thatopaquelabelsbeput over
the M27W402 window to prevent unintentional
erasure. The recommended erasureprocedure for
the M27W402 is exposureto shortwave ultraviolet
light which haswavelength 2537Å. The integrated
dose (i.e. UV intensityx exposure time) forerasure
should be a minimum of 15 W-sec/cm2. The erasure time with this dosage is approximately 15 to
20 minutes using an ultraviolet lamp with 12000
µW/cm2power rating. The M27W402 should be
placed within 2.5cm (1inch) of thelamptubes during the erasure. Some lamps havea filter on their
tubes which should be removed before erasure.
9/15
Page 10
M27W402
Table 11. OrderingInformation Scheme
Example:M27W402-100 K6 TR
Device Type
M27
SupplyVoltage
W = 2.7V to 3.6V
Device Function
402 = 4 Mbit (256Kb x16)
Speed
(1,2)
-100
-120 = 120 ns
= 100 ns
Not For New Design
(3)
-150 = 150 ns
-200 = 200 ns
Package
F = FDIP40W
(4)
B = PDIP40
K = PLCC44
N = TSOP40: 10 x20 mm
(4)
Temperature Range
6=–40to85°C
Options
TR = Tape& Reel Packing
Note: 1. High Speed, seeAC Characteristics section for further information.
2. This speed also guarantees 80ns access time at V
3. These speeds are replaced by the 120ns.
4. Packages option available on request. Please contact STMicroelectronics local Sales Office.
= 3.0V to3.6V.
CC
For a list of available options (Speed, Package, etc...) or for further information on any aspect of this device, please contactthe STMicroelectronics Sales Office nearest to you.
Table 12. Revision History
DateRevision Details
July 1999First Issue
FDIP42W Package Dimension, L Max added (Table 13)
03/15/00
10/15
TSOP40 Package Dimension changed (Table 16)
0to70°C Temperature Range deleted
Programming Time changed
Page 11
M27W402
Table 13. FDIP40W - 40 pin Ceramic Frit-seal DIP with window, Package Mechanical Data
Figure 11. TSOP40 - 40 lead Plastic Thin Small Outline, 10 x 20 mm, Package Outline
A2
1N
e
E
B
N/2
D1
D
DIE
A
CP
C
TSOP-a
Drawing is notto scale.
LA1α
14/15
Page 15
M27W402
Information furnished is believed tobe accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences
of use ofsuch information norfor any infringement ofpatents orother rightsof 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. STMicroelectronics products are not
authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.
The ST logo is registered trademark of STMicroelectronics
2000 STMicroelectronics - All Rights Reserved
All other names are the property of their respective owners.
Australia - Brazil - China - Finland - France - Germany - Hong Kong - India - Italy - Japan - Malaysia -Malta - Morocco -
Singapore - Spain - Sweden - Switzerland- United Kingdom - U.S.A.
STMicroelectronics GROUP OF COMPANIES
http://www.st.com
15/15
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