M27C256B
256 Kbit (32Kb × 8) UV EPROM and OTP EPROM
Feature summary
■
■
■
5V ± 10% supply voltage in Read operation
Access time: 45ns
Low power consumption:
– Active Current 30mA at 5MHz
– Standby Current 100µA
Programming voltage: 12.75V ± 0.25V
Programming time: 100µs/Word
Electronic signature
– Manufacturer Code: 20h
– Device Code: 8Dh
ECOPACK® packages available
PDIP28 (B)
28
28
1
FDIP28W (F)
■
■
■
1
■
PLCC32 (C)
May 2006
Rev 2
1/24
www.st.com
1
Contents
M27C256B
Contents
1
2
Summary description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Device operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
2.10
Read mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Standby mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Two-line output control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
System considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
PRESTO II programming algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Program inhibit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Program Verify . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Electronic signature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Erasure operation (applies for UV EPROM) . . . . . . . . . . . . . . . . . . . . . . . 11
3
4
5
6
7
Maximum rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
DC and AC parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Package mechanical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Part numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2/24
M27C256B
List of tables
List of tables
Table 1.
Table 2.
Table 3.
Table 4.
Table 5.
Table 6.
Table 7.
Table 8.
Table 9.
Table 10.
Table 11.
Table 12.
Table 13.
Table 14.
Table 15.
Table 16.
Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Operating modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Electronic signature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
AC measurement conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Capacitance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Read mode DC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Programming mode DC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Read mode AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Read mode AC characteristics 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Programming mode AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
FDIP28WB - 28 pin Ceramic Frit-seal DIP, with window (round 0.280"),
package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
PDIP28 - 28 pin Plastic DIP, 600 mils width, package mechanical data . . . . . . . . . . . . . . 20
PLCC32 - 32 pin Rectangular Plastic Leaded Chip Carrier, package
mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3/24
List of figures
M27C256B
List of figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
DIP connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
LCC connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Programming flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
AC testing input output waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
AC testing load circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Read mode AC waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Programming and Verify modes AC waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
FDIP28WB - 28 pin Ceramic Frit-seal DIP, with window, package outline . . . . . . . . . . . . . 19
PDIP28 - 28 pin Plastic DIP, 600 mils width, package outline . . . . . . . . . . . . . . . . . . . . . . 20
PLCC32 - 32 pin Rectangular Plastic Leaded Chip Carrier, package outline. . . . . . . . . . . 21
4/24
M27C256B
Summary description
1
Summary description
The M27C256B is a 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
organized as 32,768 by 8 bits.
The FDIP28W (window ceramic frit-seal package) has a 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 one time and erasure is not
required, the M27C256B is offered in PDIP28 and PLCC32 packages.
In order to meet environmental requirements, ST offers the M27C256B in ECOPACK®
packages.
ECOPACK packages are Lead-free. The category of second Level Interconnect is marked
on the package and on the inner box label, in compliance with JEDEC Standard JESD97.
The maximum ratings related to soldering conditions are also marked on the inner box label.
ECOPACK is an ST trademark. ECOPACK specifications are available at:
www.st.com.
Figure 1.
Logic diagram
VCC
VPP
15
A0-A14
8
Q0-Q7
E
G
M27C256B
VSS
AI00755B
5/24
