M27W256
256 Kbit (32Kb x 8) Low Voltage UV EPROM and OTP EPROM
s
2.7V to 3.6V SUPPLY VOLTAGE in READ
OPERATION
ACCESS TIME:
– 70ns at V
CC
= 3.0V to 3.6V
– 80ns at V
CC
= 2.7V to 3.6V
28
28
s
s
s
PIN COMPATIBLE with M27C256B
LOW POWER CONSUMPTION:
– 15µA max Standby Current
– 15mA max Active Current at 5MHz
1
1
FDIP28W (F)
PDIP28 (B)
s
s
PROGRAMMING TIME 100µs/byte
HIGH RELIABILITY CMOS TECHNOLOGY
– 2,000V ESD Protection
– 200mA Latchup Protection Immunity
PLCC32 (K)
s
ELECTRONIC SIGNATURE
– Manufacturer Code: 20h
– Device Code: 3Dh
Figure 1. Logic Diagram
TSOP28 (N)
8 x 13.4mm
DESCRIPTION
The M27W256 is a low voltage 256 Kbit EPROM
offered in the two ranges UV (ultra violet erase)
and OTP (one time programmable). It is ideally
suited for microprocessor systems and is orga-
nized as 32,768 by 8 bits.
The M27W256 operates in the read mode with a
supply voltage as low as 3V. The decrease in op-
erating power allows either a reduction of the size
of the battery or an increase in the time between
battery recharges.
The FDIP28W (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 applications where the content is programmed
only one time and erasure is not required, the
M27W256 is offered in PDIP28, PLCC32 and
TSOP28 (8 x 13.4 mm) packages.
VCC
VPP
15
A0-A14
8
Q0-Q7
E
G
M27W256
VSS
AI03629
March 2000
1/15
M27W256
Figure 2A. DIP Connections
Figure 2B. LCC Connections
AI03627
Q1
Q2
VSS
DU
Q3
Q4
Q5
AI03626
VPP
A12
A7
A6
A5
A4
A3
A2
A1
A0
Q0
Q1
Q2
VSS
1
28
2
27
3
26
4
25
5
24
6
23
7
22
M27W256
8
21
9
20
10
19
11
18
12
17
13
16
14
15
VCC
A14
A13
A8
A9
A11
G
A10
E
Q7
Q6
Q5
Q4
Q3
A6
A5
A4
A3
A2
A1
A0
NC
Q0
A7
A12
VPP
DU
VCC
A14
A13
1 32
A8
A9
A11
NC
G
A10
E
Q7
Q6
9
M27W256
25
17
Figure 2C. TSOP Connections
Table 1. Signal Names
A0-A14
Q0-Q7
Address Inputs
Data Outputs
Chip Enable
Output Enable
Program Supply
Supply Voltage
Ground
Not Connected Internally
Don’t Use
G
A11
A9
A8
A13
A14
VCC
VPP
A12
A7
A6
A5
A4
A3
22
21
28
1
M27W256
15
14
7
8
AI03628
A10
E
Q7
Q6
Q5
Q4
Q3
VSS
Q2
Q1
Q0
A0
A1
A2
E
G
V
PP
V
CC
V
SS
NC
DU
2/15
M27W256
Table 2. Absolute Maximum Ratings
(1)
Symbol
T
A
T
BIAS
T
STG
V
IO (2)
V
CC
V
A9 (2)
V
PP
Parameter
Ambient Operating Temperature
(3)
Temperature Under Bias
Storage Temperature
Input or Output Voltage (except A9)
Supply Voltage
A9 Voltage
Program Supply Voltage
Value
–40 to 125
–50 to 125
–65 to 150
–2 to 7
–2 to 7
–2 to 13.5
–2 to 14
Unit
°C
°C
°C
V
V
V
V
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
CC
+0.5V with possible overshoot to V
CC
+2V for a period less than 20ns.
3. Depends on range.
Table 3. Operating Modes
Mode
Read
Output Disable
Program
Verify
Program Inhibit
Standby
Electronic Signature
Note: X = V
IH
or V
IL
, V
ID
= 12V
±
0.5V.
E
V
IL
V
IL
V
IL
Pulse
V
IH
V
IH
V
IH
V
IL
G
V
IL
V
IH
V
IH
V
IL
V
IH
X
V
IL
A9
X
X
X
X
X
X
V
ID
V
PP
V
CC
V
CC
V
PP
V
PP
V
PP
V
CC
V
CC
Q7-Q0
Data Out
Hi-Z
Data In
Data Out
Hi-Z
Hi-Z
Codes
Table 4. Electronic Signature
Identifier
Manufacturer’s Code
Device Code
A0
V
IL
V
IH
Q7
0
1
Q6
0
0
Q5
1
0
Q4
0
0
Q3
0
1
Q2
0
1
Q1
0
0
Q0
0
1
Hex Data
20h
8Dh
3/15
M27W256
Table 5. AC Measurement Conditions
High Speed
Input Rise and Fall Times
Input Pulse Voltages
Input and Output Timing Ref. Voltages
≤
10ns
0 to 3V
1.5V
Standard
≤
20ns
0.4V to 2.4V
0.8V and 2V
Figure 3. AC Testing Input Output Waveform
Figure 4. AC Testing Load Circuit
1.3V
High Speed
3V
1.5V
0V
DEVICE
UNDER
TEST
2.0V
0.8V
AI01822
1N914
3.3kΩ
Standard
2.4V
OUT
CL
0.4V
CL = 30pF for High Speed
CL = 100pF for Standard
CL includes JIG capacitance
AI01823B
Table 6. Capacitance
(1)
(T
A
= 25
°C,
f = 1 MHz)
Symbol
C
IN
C
OUT
Parameter
Input Capacitance
Output Capacitance
Test Condit ion
V
IN
= 0V
V
OUT
= 0V
Min
Max
6
12
Unit
pF
pF
Note: 1. Sampled only, not 100% tested.
DEVICE OPERATION
The modes of operation of the M27W256 are listed
in the Operating Modes. A single power supply is
required in the read mode. All inputs are TTL lev-
els except for V
PP
and 12V on A9 for Electronic
Signature.
Read Mode
The M27W256 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
(t
AVQV
) is equal to the delay from E to output
(t
ELQV
). Data is available at the output after 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 M27W256 has a standby mode which reduc-
es the supply current from 10mA to 10µA with low
voltage operation V
CC
≤
3.6V, see Read Mode DC
Characteristics table for details. The M27W256 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.
4/15
M27W256
Table 7. Read Mode DC Characteristics
(1)
(T
A
= –40 to 85°C; V
CC
= 2.7V to 3.6V; V
PP
= V
CC
)
Symbol
I
LI
I
LO
I
CC
I
CC1
I
CC2
I
PP
V
IL
V
IH (2)
V
OL
V
OH
Parameter
Input Leakage Current
Output Leakage Current
Supply Current
Supply Current (Standby) TTL
Supply Current (Standby) CMOS
Program Current
Input Low Voltage
Input High Voltage
Output Low Voltage
Output High Voltage TTL
I
OL
= 2.1mA
I
OH
= –400µA
2.4
Test Condition
0V
≤
V
IN
≤
V
CC
0V
≤
V
OUT
≤
V
CC
E = V
IL
, G = V
IL
,
I
OUT
= 0mA, f = 5MHz,
V
CC
≤
3.6V
E = V
IH
E > V
CC
– 0.2V,
V
CC
≤
3.6V
V
PP
= V
CC
–0.6
0.7 V
CC
1
15
100
0.2 V
CC
V
CC
+ 0.5
0.4
mA
µA
µA
V
V
V
V
Min
Max
±10
±10
15
Unit
µA
µA
mA
Note: 1. V
CC
must be applied simultaneously with or before V
PP
and removed simultaneously or after V
PP
.
2. Maximum DC voltage on Output is V
CC
+0.5V.
Table 8. Read Mode AC Characteristics
(1)
(T
A
= –40 to 85°C; V
CC
= 2.7V to 3.6V; V
PP
= V
CC
)
M27W256
Test
Condition
Min
t
AVQV
t
ELQV
t
GLQV
t
EHQZ (2)
t
GHQZ (2)
t
AXQX
t
ACC
t
CE
t
OE
t
DF
t
DF
t
OH
Address Valid to
Output Valid
Chip Enable Low to
Output Valid
Output Enable Low
to Output Valid
Chip Enable High
to Output Hi-Z
Output Enable High
to Output Hi-Z
Address Transition
to Output Transition
E = V
IL
,
G = V
IL
G = V
IL
E = V
IL
G = V
IL
E = V
IL
E = V
IL
,
G = V
IL
0
0
0
-80
(3)
-100
(-120/-150/-200)
Symbol
Alt
Parameter
Unit
V
CC
= 3.0V to 3.6V V
CC
= 2.7V to 3.6V V
CC
= 2.7V to 3.6V
Max
70
70
40
40
40
Min
Max
80
80
50
Min
Max
100
100
60
ns
ns
ns
ns
ns
ns
0
0
0
50
50
0
0
0
60
60
Note: 1. V
CC
must be applied simultaneously with or before V
PP
and removed simultaneously or after V
PP
.
2. Sampled only, not 100% tested.
3. Speed obtained with High Speed AC measurement conditions.
5/15
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