PRELIMINARY
MX27C2000A
2M-BIT [256K x 8] CMOS EPROM
FEATURES
•
•
•
•
•
•
256Kx 8 organization
Single +5V power supply
+12.5V programming voltage
Fast access time:90/100/120/150 ns
Totally static operation
Completely TTL compatible
•
Operating current:30mA
•
Standby current: 100uA
•
Package type:
-
-
-
-
32 pin plastic DIP
32 pin PLCC
32 pin SOP
32 pin TSOP
GENERAL DESCRIPTION
The MX27C2000A is a 5V only, 2M-bit, One Time
Programmable Read Only Memory. It is organized as
256K words by 8 bits per word, operates from a single +
5 volt supply, has a static standby mode, and features
fast single address location programming. All program-
ming signals are TTL levels, requiring a single pulse. For
programming outside from the system, existing EPROM
programmers may be used. The MX27C2000A supports
a intelligent fast programming algorithm which can result
in programming time of less than one minute.
This One Time Programmable Read Only is packaged in
industry standard 32 pin dual-in-line packages, 32 lead
PLCC, 32 lead SOP, 32 lead TSOP packages.
PIN CONFIGURATIONS
32 PDIP/SOP
VPP
A16
A15
A12
A7
A6
A5
A4
A3
A2
A1
A0
Q0
Q1
Q2
GND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
VCC
PGM
A17
A14
A13
A8
A9
A11
OE
A10
CE
Q7
Q6
Q5
Q4
Q3
32 PLCC
PGM
VCC
VPP
A12
A15
A16
4
1
32
30
29
A17
A7
A6
A5
A4
A3
A2
A1
A0
Q0
5
A14
A13
A8
A9
MX27C2000A
9
MX27C2000A
25
A11
OE
A10
CE
13
14
17
21
20
Q7
Q1
Q2
GND
Q3
Q4
Q5
32 TSOP
A11
A9
A8
A13
A14
A17
PGM
VCC
VPP
A16
A15
A12
A7
A6
A5
A4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
OE
A10
CE
Q7
Q6
Q5
Q4
Q3
GND
Q2
Q1
Q0
A0
A1
A2
A3
PIN DESCRIPTION
SYMBOL
A0~A17
Q0~Q7
CE
OE
PGM
VPP
NC
VCC
GND
PIN NAME
Address Input
Data Input/Output
Chip Enable Input
Output Enable Input
Programmable Enable Input
Program Supply Voltage
No Internal Connection
Power Supply Pin (+5V)
Ground Pin
MX27C2000A
Q6
P/N: PM0708
REV. 2.0, AUG. 27, 2003
1
MX27C2000A
BLOCK DIAGRAM
CE
PGM
OE
CONTROL
LOGIC
OUTPUT
BUFFERS
Q0~Q7
PROGRAM INHIBIT MODE
Programming of multiple MX27C2000As 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 MX27C2000A may be common. A
TTL low-level program pulse applied to an MX27C2000A
CE input with VPP = 12.5
±
0.5 V and PGM LOW will
program that MX27C2000A. A high-level CE input
inhibits the other MX27C2000A from being programmed.
A0~A17
ADDRESS
INPUTS
.
.
.
.
.
.
.
.
Y-DECODER
.
.
.
.
.
.
.
.
Y-SELECT
X-DECODER
2M BIT
CELL
MAXTRIX
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.
VCC
VSS
VPP
FUNCTIONAL DESCRIPTION
THE PROGRAMMING OF THE MX27C2000A
When the MX27C2000A is delivered, or it is erased, the
chip has all 2M bits in the "ONE", or HIGH state.
"ZEROs" are loaded into the MX27C2000A 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 0.1uF capacitor is
required across VPP and ground to suppress spurious
voltage transients which may damage the device.
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° ambient temperature range
C
that is required when programming the MX27C2000A.
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
MX27C2000A, 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 = 6.25V and PGM = VIH (Algorithm is shown in
Figure 1). The programming is achieved by applying a
single TTL low level 10us 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%.
READ MODE
The MX27C2000A 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)
P/N: PM0708
2
REV. 2.0, AUG. 27, 2003
MX27C2000A
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.
It is recommended that CE be decoded and used as the
primary device-selecting function, while OE be made a
common connection to all devices in the array and
connected to the READ line from the system control bus.
This assures that all deselected memory devices are in
their low-power standby mode and that the output pins
are only active when data is desired from a particular
memory device.
STANDBY MODE
SYSTEM CONSIDERATIONS
The MX27C2000A has a CMOS standby mode which
reduces the maximum VCC current to 100 uA. It is
placed in CMOS standby when CE is at VCC
±
0.3 V. The
MX27C2000A also has a TTL-standby mode which
reduces the maximum VCC current to 1.5 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.
During the switch between active and standby
conditions, transient current peaks are produced on the
rising and falling edges of Chip Enable. The magnitude
of these transient current peaks is dependent on the
output capacitance loading of the device. At a minimum,
a 0.1 uF ceramic capacitor (high frequency, low inherent
inductance) should be used on each device between Vcc
and GND to minimize transient effects. In addition, to
overcome the voltage drop caused by the inductive
effects of the printed circuit board traces on EPROM
arrays, a 4.7 uF bulk electrolytic capacitor should be
used between VCC and GND for each eight devices. The
location of the capacitor should be close to where the
power supply is connected to the array.
TWO-LINE OUTPUT CONTROL FUNCTION
To accommodate multiple memory connections, a two-
line control function is provided to allow for:
1. Low memory power dissipation,
2. Assurance that output bus contention will not
occur.
MODE SELECT TABLE
PINS
MODE
Read
Output Disable
Standby (TTL)
Standby (CMOS)
Program
Program Verify
Program Inhibit
Manufacturer Code(3)
Device Code(3)
CE
VIL
VIL
VIH
VCC±0.3V
VIL
VIL
VIH
VIL
VIL
OE
VIL
VIH
X
X
VIH
VIL
X
VIL
VIL
PGM
X
X
X
X
VIL
VIH
X
X
X
A0
X
X
X
X
X
X
X
VIL
VIH
A9
X
X
X
X
X
X
X
VH
VH
VPP
VCC
VCC
VCC
VCC
VPP
VPP
VPP
VCC
VCC
OUTPUTS
DOUT
High Z
High Z
High Z
DIN
DOUT
High Z
C2H
C3H
NOTES:
1.VH = 12.0 V
±
0.5 V
2.X = Either VIH or VIL
3.A1 - A8 = A10 - A17 = VIL(For auto select)
4.See DC Programming Characteristics for VPP voltage during programming.
P/N: PM0708
3
REV. 2.0, AUG. 27, 2003
MX27C2000A
FIGURE 1. FAST PROGRAMMING FLOWCHART
START
ADDRESS = FIRST LOCATION
VCC = 6.25V
VPP = 12.75V
X=0
PROGRAM ONE 10us PULSE
INTERACTIVE
SECTION
INCREMENT X
YES
X = 25?
NO
FAIL
VERIFY BYTE
?
PASS
NO
INCREMENT ADDRESS
LAST ADDRESS
FAIL
YES
VCC = VPP = 5.25V
VERIFY SECTION
VERIFY ALL BYTES
?
FAIL
DEVICE FAILED
PASS
DEVICE PASSED
P/N: PM0708
4
REV. 2.0, AUG. 27, 2003
MX27C2000A
SWITCHING TEST CIRCUITS
DEVICE
UNDER
TEST
1.8K ohm
+5V
CL
6.2K ohm
DIODES = IN3064
OR EQUIVALENT
CL = 100 pF including jig capacitance
SWITCHING TEST WAVEFORMS
2.0V
AC driving levels
2.0V
TEST POINTS
0.8V
OUTPUT
0.8V
INPUT
AC TESTING: AC driving levels are 2.4V/0.4V for commercial grade.
Input pulse rise and fall times are equal to or less than 10ns.
P/N: PM0708
5
REV. 2.0, AUG. 27, 2003
Embedded System
京公网安备 11010802033920号
EEWORLD
