MX27L512TI-20 Ver la hoja de datos (PDF) - Macronix International
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MX27L512TI-20 Datasheet PDF : 14 Pages
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MX27L512
FUNCTIONAL DESCRIPTION
THE PROGRAMMING OF THE MX27L512
When the MX27L512 is delivered, or it is erased, the
chip has all 512K bits in the "ONE", or HIGH state.
"ZEROs" are loaded into the MX27L512 through the
procedure of programming.
For programming, the data to be programmed is applied
with 8 bits in parallel to the data pins.
Vcc must be applied simultaneously or before Vpp, and
removed simultaneously or after Vpp. When
programming an MXIC EPROM, a 0.1uF capacitor is
required across Vpp and ground to suppress spurious
voltage transients which may damage the device.
FAST PROGRAMMING
The device is set up in the fast programming mode when
the programming voltage OE/VPP = 12.75V is applied,
with VCC = 6.25 V, (Algorithm is shown in Figure 1). The
programming is achieved by applying a single TTL low
level 100us pulse to the CE input after addresses and
data line are stable. If the data is not verified, an
additional pulse is applied for a maximum of 25 pulses.
This process is repeated while sequencing through each
address of the device. When the programming mode is
completed, the data in all address is verified at VCC = 5V
± 10%.
PROGRAM INHIBIT MODE
Programming of multiple MX27L512s in parallel with
different data is also easily accomplished by using the
Program Inhibit Mode. Except for CE and OE, all like
inputs of the parallel MX27L512 may be common. A TTL
low-level program pulse applied to an MX27L512 CE
input with OE/VPP = 12.5 ± 0.5V will program that
MX27L512. A high-level CE input inhibits the other
MX27L512s from being programmed.
PROGRAM VERIFY MODE
Verification should be performed on the programmed
bits to determine that they were correctly programmed.
The verification should be performed with OE/VPP and
CE, at VIL. Data should be verified tDV after the falling
edge of CE.
AUTO IDENTIFY MODE
The auto identify mode allows the reading out of a binary
code from an EPROM that will identify its manufacturer
and device type. This mode is intended for use by
programming equipment for the purpose of
automatically matching the device to be programmed
with its corresponding programming algorithm. This
mode is functional in the 25°C ± 5°C ambient
temperature range that is required when programming
the MX27L512.
To activate this mode, the programming equipment
must force 12.0 ± 0.5(VH) on address line A9 of the
device. Two identifier bytes may then be sequenced
from the device outputs by toggling address line A0 from
VIL to VIH. All other address lines must be held at VIL
during auto identify mode.
Byte 0 ( A0 = VIL) represents the manufacturer code,
and byte 1 (A0 = VIH), the device identifier code. For the
MX27L512, these two identifier bytes are given in the
Mode Select Table. All identifiers for manufacturer and
device codes will possess odd parity, with the MSB (Q7)
defined as the parity bit.
READ MODE
The MX27L512 has two control functions, both of which
must be logically satisfied in order to obtain data at the
outputs. Chip Enable (CE) is the power control and
should be used for device selection. Output Enable
(OE) is the output control and should be used to gate
data to the output pins, independent of device selection.
Assuming that addresses are stable, address access
time (tACC) is equal to the delay from CE to output (tCE).
Data is available at the outputs tOE after the falling edge
of OE, assuming that CE has been LOW and addresses
have been stable for at least tACC - tOE.
STANDBY MODE
The MX27L512 has a CMOS standby mode which
reduces the maximum VCC current to 10 uA. It is placed
in CMOS standby when CE is at VCC ± 0.3 V. The
MX27L512 also has a TTL-standby mode which
reduces the maximum VCC current to 0.25 mA. It is
placed in TTL-standby when CE is at VIH. When in
standby mode, the outputs are in a high-impedance
state, independent of the OE input.
P/N:PM0256
REV. 2.6, AUG. 26, 2003
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