EPROM. M27512 Datasheet

M27512 Datasheet PDF

Part M27512
Description NMOS 512K 64K x 8 UV EPROM
Feature M27512; M27512 NMOS 512K (64K x 8) UV EPROM FAST ACCESS TIME: 200ns EXTENDED TEMPERATURE RANGE SINGLE 5V SUP.
Manufacture STMicroelectronics
Datasheet
Download M27512 Datasheet




M27512
M27512
NMOS 512K (64K x 8) UV EPROM
FAST ACCESS TIME: 200ns
EXTENDED TEMPERATURE RANGE
SINGLE 5V SUPPLY VOLTAGE
LOW STANDBY CURRENT: 40mA max
TTL COMPATIBLE DURING READ and
PROGRAM
FAST PROGRAMMING ALGORITHM
ELECTRONIC SIGNATURE
PROGRAMMING VOLTAGE: 12V
28
1
FDIP28W (F)
DESCRIPTION
The M27512 is a 524,288 bit UV erasable and
electrically programmable memory EPROM. It is
organized as 65,536 words by 8 bits.
The M27512 is housed in a 28 Pin Window Ceramic
Frit-Seal Dual-in-Line package. The transparent lid
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.
Figure 1. Logic Diagram
VCC
16
A0-A15
Table 1. Signal Names
A0 - A15
Q0 - Q7
E
GVPP
VCC
VSS
Address Inputs
Data Outputs
Chip Enable
Output Enable / Program Supply
Supply Voltage
Ground
E
GVPP
M27512
VSS
8
Q0-Q7
AI00765B
March 1995
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M27512
M27512
Table 2. Absolute Maximum Ratings
Symbol
Parameter
Value
Unit
TA Ambient Operating Temperature
Grade 1
Grade 6
0 to 70
–40 to 85
°C
TBIAS
Temperature Under Bias
Grade 1
Grade 6
–10 to 80
–50 to 95
°C
TSTG
Storage Temperature
–65 to 125
°C
VIO Input or Output Voltages
–0.6 to 6.5
V
VCC Supply Voltage
–0.6 to 6.5
V
VA9 A9 Voltage
–0.6 to 13.5
V
VPP Program Supply
–0.6 to 14
V
Note: 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 conditions for extended periods
may affect device reliability. Refer also to the SGS-THOMSON SURE Program and other relevant quality document
Figure 2. DIP Pin Connections
A15 1
A12 2
28 VCC
27 A14
A7 3
26 A13
A6 4
25 A8
A5 5
24 A9
A4 6
23 A11
A3 7 M27512 22 GVPP
A2 8
21 A10
A1 9
20 E
A0 10
19 Q7
Q0 11
18 Q6
Q1 12
17 Q5
Q2 13
16 Q4
VSS 14
15 Q3
AI00766
DEVICE OPERATION
The six modes of operations of the M27512 are
listed in the Operating Modes table. A single 5V
power supply is required in the read mode. All
inputs are TTL levels except for GVPP and 12V on
A9 for Electronic Signature.
Read Mode
The M27512 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, inde-
pendent of device selection. Assuming that the
addresses are stable, address access time (tAVQV)
is equal to the delay from E to output (tELQV). Data
is available at the outputs after delay of tGLQV from
the falling edge of G, assuming that E has been low
and the addresses have been stable for at least
tAVQV-tGLQV.
Standby Mode
The M27512 has a standby mode which reduces
the maximum active power current from 125mA to
40mA. The M27512 is placed in the standby mode
by applying a TTL high signal to the E input. When
in the standby mode, the outputs are in a high
impedance state, independent of the GVPP input.
Two Line Output Control
Because EPROMs are usually used in larger mem-
ory arrays, the 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.
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M27512
M27512
DEVICE OPERATION (cont’d)
For the most efficient use of these two control lines,
E should be decoded and used as the primary
device selecting function, while GVPP 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 dese-
lected memory devices are in their low power
standby mode and that the output pins are only
active when data is required from a particular mem-
ory device.
System Considerations
The power switching characteristics of fast
EPROMs require careful 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 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 sup-
pressed by complying with the two line output
control and by properly selected decoupling ca-
pacitors. It is recommenced that a 1µF ceramic
capacitor be used on every device between VCC
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 VCC and VSS for every eight devices. 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.
Programming
When delivered, and after each erasure, all bits of
the M27512 are in the “1" state. Data is introduced
by selectively programming ”0s" into the desired bit
locations. Although only “0s” will be programmed,
both “1s” and “0s” can be present in the data word.
The only way to change a “0" to a ”1" is by ultraviolet
light erasure. The M27512 is in the programming
mode when GVPP input is at 12.5V and E is at
TTL-low. The data to be programmed is applied 8
bits in parallel to the data output pins. The levels
required for the address and data inputs are TTL.
The M27512 can use PRESTO Programming Algo-
rithm that drastically reduces the programming
time (typically less than 50 seconds). Nevertheless
to achieve compatibility with all programming
equipment, the standard Fast Programming Algo-
rithm may also be used.
Fast Programming Algorithm
Fast Programming Algorithm rapidly programs
M27512 EPROMs using an efficient and reliable
method suited to the production programming en-
vironment. Programming reliability is also ensured
as the incremental program margin of each byte is
continually monitored to determine when it has
been successfully programmed. A flowchart of the
M27512 Fast Programming Algorithm is shown in
Figure 8.
Table 3. Operating Modes
Mode
Read
Output Disable
Program
Verify
Program Inhibit
Standby
Electronic Signature
Note: X = VIH or VIL, VID = 12V ± 0.5%.
E
VIL
VIL
VIL Pulse
VIH
VIH
VIH
VIL
GVPP
VIL
VIH
VPP
VIL
VPP
X
VIL
A9 Q0 - Q7
X Data Out
X Hi-Z
X Data In
X Data Out
X Hi-Z
X Hi-Z
VID Codes
Table 4. Electronic Signature
Identifier
A0 Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q0 Hex Data
Manufacturer’s Code VIL
0
0
1
0
0
0
0
0
20h
Device Code
VIH 0 0 0 0 1 1 0 1
0Dh
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