M27C256B-70XF1 STMicroelectronics, M27C256B-70XF1 Datasheet - Page 10

• Manufacturer Part Number: M27C256B-70XF1
• Description: IC EPROM 256KBIT 70NS 28CDIP
• Manufacturer: STMicroelectronics

Specifications of M27C256B-70XF1

• Format - Memory: EPROMs
• Memory Type: UV EPROM
• Memory Size: 256K (32K x 8)
• Speed: 70ns
• Interface: Parallel
• Voltage - Supply: 4.75 V ~ 5.25 V
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 28-CDIP (0.600", 15.24mm) Window
• Capacitance, Input: 6 pF
• Capacitance, Output: 12 pF
• Current, Input, Leakage: ±10 μA (Read)
• Current, Operating: 30 mA (Read)
• Current, Output, Leakage: ±10 μA (Read)
• Density: 256K
• Organization: 32K×8
• Package Type: FDIP28W
• Temperature, Operating: 0 to +70 °C
• Time, Access: 70 ns
• Time, Fall: ≤20 ns
• Time, Rise: ≤20 ns
• Voltage, Input, High: 6 V (Read)
• Voltage, Input, Low: 0.8 V (Read)
• Voltage, Output, High: 4.3 V (Read)
• Voltage, Output, Low: 0.4 V (Read)
• Voltage, Supply: 5 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Device operation
2.7
2.8
2.9
10/24
Figure 4.
Program inhibit
Programming of multiple M27C256Bs in parallel with different data is also easily
accomplished. Except for E, all like inputs including G of the parallel M27C256B may be
common. A TTL low level pulse applied to a M27C256B's E input, with V
program that M27C256B. A high level E input inhibits the other M27C256Bs from being
programmed.
Program Verify
A verify (read) should be performed on the programmed bits to determine that they were
correctly programmed. The verify is accomplished with G at V
V
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 ± 5°C
ambient temperature range that is required when programming the M27C256B. To activate
the ES mode, the programming equipment must force 11.5V to 12.5V on address line A9 of
the M27C256B, with V
device outputs by toggling address line A0 from V
held at V
code and byte 1 (A0 = V
M27C256B, these two identifier bytes are given in
Q7 to Q0.
CC
at 6.25V.
IL
during Electronic Signature mode. Byte 0 (A0 = V
Programming flowchart
CC
IH
= V
) the device identifier code. For the STMicroelectronics
YES
NO
PP
FAIL
= 25
++n
= 5V. Two identifier bytes may then be sequenced from the
V CC = 6.25V, V PP = 12.75V
CHECK ALL BYTES
NO
2nd: V CC = 4.2V
E = 100 s Pulse
1st: V CC = 6V
VERIFY
n = 0
Addr
Last
YES
YES
IL
NO
Table 3
to V
++ Addr
IH
. All other address lines must be
and can be read-out on outputs
AI00760B
IL
IL
) represents the manufacturer
, E at V
IH
, V
PP
PP
at 12.75V, will
at 12.75V and
M27C256B