MX27C4000A
BLOCK DIAGRAM
CE
OE
CONTROL
LOGIC
OUTPUT
BUFFERS
Q0~Q7
PROGRAM INHIBIT MODE
Programming of multiple MX27C4000As 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 MX27C4000A may be common. A
TTL low-level program pulse applied to an
MX27C4000A CE input with VPP = 12.5
±
0.5 V and CE
LOW will program that MX27C4000A. A high-level CE
input inhibits the other MX27C4000As from being
programmed.
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.
.
A0~A18
ADDRESS
INPUTS
.
.
.
.
.
VCC
VSS
Y-DECODER
.
.
.
.
.
.
.
.
Y-SELECT
4M BIT
CELL
MAXTRIX
X-DECODER
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, and VPP at its programming voltage.
FUNCTIONAL DESCRIPTION
THE PROGRAMMING OF THE MX27C4000A
AUTO IDENTIFY MODE
When the MX27C4000A is delivered, or it is erased,
the chip has all 4M bits in the "ONE" or HIGH state.
"ZEROs" are loaded into the MX27C4000A 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 OTP ROM, a 01uF capacitor is
required across Vpp and ground to suppress spurious
voltage transients which may damage the device.
The auto identify mode allows the reading out of a binary
code from an OTP ROM 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 MX27C4000A.
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
MX27C4000A, 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.
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 OE = VIH (Algorithm is shown in
Figure 1). The programming is achieved by applying a
single TTL low level 10us 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 = VPP = 5V
±
10%.
READ MODE
The MX27C4000A has two control functions, both of
which must be logically satisfied in order to obtain data
P/N: PM00694
REV. 1.6, JUL. 19, 2001
2
MCNIX [ MACRONIX INTERNATIONAL ]
