MX27L2000DC-12 データシートの表示（PDF） - Macronix International
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MX27L2000DC-12 Datasheet PDF : 14 Pages
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INDEX
MX27L2000
FUNCTIONAL DESCRIPTION
THE ERASURE OF THE MX27L2000
The MX27L2000 is erased by exposing the chip to an
ultraviolet light source. A dosage of 15 W seconds/cm2 is
required to completely erase a MX27L2000. This dosage
can be obtained by exposure to an ultraviolet lamp -
wavelength of 2537 Angstroms (A) - with intensity of
12,000 uW/cm2 for 15 to 20 minutes. The MX27L2000
should be directly under and about one inch from the
source and all filters should be removed from the UV light
source prior to erasure.
It is important to note that the MX27L2000, and similar
devices, will be cleared for all bits of their programmed
states with light sources having wavelengths shorter than
4000 A. Although erasure times will be much longer than
that with UV sources at 2537 A, nevertheless the
exposure to fluorescent light and sunlight will eventually
erase the MX27L2000 and exposure to them should be
prevented to realize maximum system reliability. If used
in such an environment, the package window should be
covered by an opaque label or substance.
THE PROGRAMMING OF THE MX27L2000
When the MX27L2000 is delivered, or it is erased, the
chip has all 2M bits in the "ONE" or HIGH state. "ZEROs"
are loaded into the MX27L2000 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 VPP = 12.75V is applied, with
VCC = 6.25 V and PGM = VIH (Algorithm is shown in
Figure 1). The programming is achieved by applying a
single TTL low level 100us pulse to the PGM 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 = VPP = 5V ± 10%.
PROGRAM INHIBIT MODE
Programming of multiple MX27L2000s 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 MX27L2000 may be common. A TTL
low-level program pulse applied to an MX27L2000 CE
input with VPP = 12.5 ± 0.5 V and PGM LOW will program
that MX27L2000. A high-level CE input inhibits the other
MX27L2000s 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 and CE, at VIL,
PGM at VIH, and VPP at its programming voltage.
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 MX27L2000.
To activate this mode, the programming equipment must
force 12.0 ± 0.5 V 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
MX27L2000, 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.
P/N: PM0372
REV.2.5, APR 09,1998
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