MXIC MX26L6420XBI-12, MX26L6420MC-90, MX26L6420TI-12, MX26L6420XAI-12, MX26L6420XAC-90 Datasheet

FEATURES

ADVANCED INFORMATION

MX26L6420

64M-BIT [4M x 16] CMOS

MULTIPLE-TIME-PROGRAMMABLE EPROM

• 4,194,304 x 16 byte structure

• Single Power Supply Operation

- 2.7 to 3.6 volt for read, erase, and program
operations

• Low Vcc write inhibit is equal to or less than 2.5V

• Compatible with JEDEC standard

• High Performance

- Fast access time: 90/120ns (typ.)

- Fast program time: 140s/chip (typ.)

- Fast erase time: 150s/chip (typ.)

• Low Power Consumption

- Low active read current: 17mA (typ.) at 5MHz

- Low standby current: 30uA (typ.)

• Minimum 100 erase/program cycle

GENERAL DESCRIPTION

The MX26L6420 is a 64M bit MTP EPROMTM organized
as 4M bytes of 16 bits. MXIC's MTP EPROM
most cost-effective and reliable read/write non-volatile
random access memory. The MX26L6420 is packaged in
44SOP, 48-pin TSOP, 48-ball CSP and 63-ball CSP. It is
designed to be reprogrammed and erased in system or in
standard EPROM programmers.

TM

offer the

• Status Reply

- Data polling & Toggle bits provide detection of
program and erase operation completion

• 12V ACC input pin provides accelerated program

capability

• Output voltages and input voltages on the device is

deterined by the voltage on the VI/O pin.

- VI/O voltage range:1.65V~3.6V

• 10 years data retention

• Package

- 44-Pin SOP

- 48-Pin TSOP

- 48-Ball CSP

- 63-Ball CSP

MXIC's MTP EPROM
memory contents even after 100 erase and program
cycles. The MXIC cell is designed to optimize the erase
and program mechanisms. In addition, the combination of
advanced tunnel oxide processing and low internal
electric fields for erase and programming operations
produces reliable cycling.

TM

technology reliably stores

The standard MX26L6420 offers access time as fast as
90ns, allowing operation of high-speed microprocessors
without wait states. To eliminate bus contention, the
MX26L6420 has separate chip enable (CE) and output
enable OE controls. MXIC's MTP EPROMTM augment
EPROM functionality with in-circuit electrical erasure and
programming. The MX26L6420 uses a command register
to manage this functionality.

P/N:PM0823 REV. 0.5, JAN. 29, 2002

The MX26L6420 uses a 2.7V to 3.6V VCC supply to
perform the High Reliability Erase and auto Program/
Erase algorithms.

The highest degree of latch-up protection is achieved with
MXIC's proprietary non-epiprocess. Latch-up protection
is proved for stresses up to 100 milliamps on address and
data pin from -1V to VCC +1V.

1

PIN CONFIGURATION
48 CSP Ball pitch=0.75mm for MX26L6420XA (TOP view, Ball down)

12345678

MX26L6420

A

B

C

D

E

F

A13

A14

A15

A16

V I/O

GND

A11

A10

A12

Q14

Q15

Q7

A8

WE

A9

Q5

Q6

Q13

ACC NC

RESET

A21

Q11

Q12

Q4

A18

A20

Q2

Q3

VCC

A19

A17

A6

Q8

Q9

Q10

A7

A5

A3

CE

Q0

Q1

13.0 mm

63 CSP Ball pitch=0.8mm for MX26L6420XB(TOP view, Ball down)

13.0 mm

8

NC

NC

A4

A2

A1

A0

GND

OE

NC*

8.0 mm

NC*

P/N:PM0823

7

6

5

4

3

2

1

* Ball are shorted together via the substrate but not connected to the die.

NC

NC

NC*

NC*

NC*

BCDEFGHJK LM

A

A13

A9

WE

NC

A7

A3

A12

A8

RESET

ACC

A17

A4

A14

A10

A21

A18

A6

A2

A15

A11

A19

A20

A5

A1

A16

VIO

Q7

Q14

Q12

Q5

Q2

Q10

Q0

Q8

A0

CE

Q15

Q13

VCC

Q11

Q9

OE

GND

Q6

Q4

Q3

Q1

GND

NC*

NC*

NC*

NC*

8.0 mm

NC*

NC*

REV. 0.5, JAN. 29, 2002

2

MX26L6420

44 SOP

A21
A18
A17

CE

GND

OE
Q0
Q8
Q1
Q9
Q2

Q10

Q3

Q11

48 TSOP

44

A20

43

2
3
4

A7

5

A6

6

A5

7

A4

8

A3

9

A2

10

A1

11

A0

12
13
14

MX26L6420

15
16
17
18
19
20
21
22

A19

42

A8

41

A9

40

A10

39

A11

38

A12

37

A13

36

A14

35

A15

34

A16

33

WE

32

GND

31

Q15

30

Q7

29

Q14

28

Q6

27

Q13

26

Q5

25

Q12

24

Q4

23

VCC

A15
A14
A13
A12
A11
A10

A21
A20

WE

RESET

ACC
VCC

A19
A18
A17

1
2
3
4
5
6
7

A9

8

A8

9
10
11
12
13
14
15
16
17
18

A7

19

A6

20

A5

21

A4

22

A3

23

A2

24

A1

MX26L6420

A16

48

V

47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25

I/O

GND
Q15
Q7
Q14
Q6
Q13
Q5
Q12
Q4
V

CC

Q11
Q3
Q10
Q2
Q9
Q1
Q8
Q0
OE
GND
CE
A0

PIN DESCRIPTION

SYMBOL PIN NAME

A0~A21 Address Input
Q0~Q15 Data Inputs/Outputs
CE Chip Enable Input
WE Write Enable Input
OE Output Enable Input
RESET Hardware Reset Pin, Active Low
VC C +3.0V single power supply
ACC Hardware Acceleration Pin
V I/O I/O power supply (For 48 TSOP and

63-CSP package only)
GN D Device Ground
N C Pin Not Connected Internally

LOGIC SYMBOL

21

A0-A21

CE
OE
WE
RESET

ACC

16

Q0-Q15

P/N:PM0823

REV. 0.5, JAN. 29, 2002

3

BLOCK DIAGRAM

CE
OE
WE

CONTROL
INPUT

LOGIC

PROGRAM/ERASE

HIGH VOLT A GE

MX26L6420

WRITE

STATE

MACHINE

(WSM)

A0-A21

ADDRESS

LATCH

AND

BUFFER

X-DECODER

MX26L6420

FLASH
ARRA Y

Y-DECODER

Y-PASS GATE

SENSE

AMPLIFIER

DATA LATCH

STATE

REGISTER

ARRAY

SOURCE

HV

COMMAND

DATA
DECODER

PGM

DATA

HV

COMMAND
DATA LATCH

PROGRAM

P/N:PM0823

Q0-Q15

I/O BUFFER

REV. 0.5, JAN. 29, 2002

4

MX26L6420

AUTOMATIC PROGRAMMING

The MX26L6420 is word programmable using the Auto­matic Programming algorithm. The Automatic Progr am­ming algorithm makes the external system do not need
to have time out sequence nor to verify the data pro­grammed. The typical chip programming time at room
temperature of the MX26L6420 is less than 150 sec­onds.

AUTOMATIC PROGRAMMING ALGORITHM

MXIC's Automatic Programming algorithm require the user
to only write program set-up commands (including 2 un­lock write cycle and A0H) and a program command (pro­gram data and address). The de vice automatically times
the programming pulse width, provides the program veri­fication, and counts the number of sequences. A status
bit similar to DATA polling and a status bit toggling be­tween consecutive read cycles, provide feedback to the
user as to the status of the programming operation.

AUTOMATIC CHIP ERASE

ming and erase operations. All address are latched on
the falling edge of WE or CE, whiche ver happens later.
All data are latched on rising edge of WE or CE, which­ever happens first.

MXIC's Flash technology combines years of EPROM
experience to produce the highest levels of quality, relia­bility, and cost effectiveness. The MX26L6420 electri­cally erases all bits simultaneously using Fowler-Nord­heim tunneling. The bytes are programmed b y using the
EPROM programming mechanism of hot electron injec­tion.

During a program cycle, the state-machine will control
the program sequences and command register will not
respond to any command set. After the state machine
has completed its task, it will allow the command regis­ter to respond to its full command set.

The entire chip is bulk erased using 50 ms erase pulses
according to MXIC's Automatic Chip Erase algorithm.
T ypical erasure at room temper ature is accomplished in
less than 90 seconds. The Automatic Erase algorithm
automatically programs the entire array prior to electrical
erase. The timing and verification of electrical erase are
controlled internally within the device.

AUTOMATIC ERASE ALGORITHM

MXIC's Automatic Erase algorithm requires the user to
write commands to the command register using stand­ard microprocessor write timings. The device will auto­matically pre-program and verify the entire arra y. Then
the device automatically times the erase pulse width,
provides the erase verification, and counts the number
of sequences. A status bit toggling between consecu­tive read cycles provides feedback to the user as to the
status of the programming operation.

Register contents serve as inputs to an internal state­machine which controls the erase and programming cir­cuitry . During write cycles, the command register inter­nally latches address and data needed for the program-

P/N:PM0823

REV. 0.5, JAN. 29, 2002

5

MX26L6420

Table 1

BUS OPERATION(1)

Operation CE OE WE RESET Address Q15~Q0

Read L L H H A
Write(Note 1) L H L H A

IN

IN

D

OUT

D

IN

Standby VCC±0.3V X X VCC±0.3V X High-Z
Output Disable L H H H X High-Z
Reset X X X L X High-Z

Legend:
L=Logic LOW=VIL,H=Logic High=VIH,VID=12.0±0.5V,X=Don't Care, AIN=Address IN, DIN=Data IN, D

=Data OUT

OUT

Notes:

1. When the ACC pin is at VHH, the device enters the accelerated program mode. See "Accelerated Prog ram Operations"
for more information.

Table 2. AUTOSELECT CODES (High Voltage Method)

A5 A8 A14

Operation CE OE WE A0 A1 to A6 to A9 to A15~A21 Q15~Q0

A2 A7 A10

Read Silicon ID L L H L L X L X V

X X00 C2 H

ID

Manufactures Code
Read Silicon ID L L H H L X L X V

X X 22FCH

ID

Device Code
Secured Silscon xx88h
Sector Indicator L L H H H X L X V

X X (factory locked)

ID

Bit (Q7) xx08h

(non-factory locked)

P/N:PM0823

REV. 0.5, JAN. 29, 2002

6

MX26L6420

REQUIREMENTS FOR READING ARRAY
DATA

To read array data from the outputs, the system must
drive the CE and OE pins to VIL. CE is the po wer control
and selects the device. OE is the output control and gates
array data to the output pins. WE should remain at VIH.

The internal state machine is set for reading array data
upon device power-up, or after a hardware reset. This
ensures that no spurious alteration of the memory contect
occurs during the power transition. No command is
necessary in this mode to obtain array data. Standard
microprocessor read cycles that assert valid address on
the device address inputs produce valid data on the device
data outputs. The de vice remains enabled for read access
until the command register contents are altered.

WRITE COMMANDS/COMMAND
SEQUENCES

To program data to the device or erase memory , the
system must drive WE and CE to VIL, and OE to VIH.

An erase operation can erase the entire device. The
"Writing specific address and data commands or
sequences into the command register initiates device
operations. Table 1 defines the valid register command
sequences. Writing incorrect address and data values or
writing them in the improper sequence resets the device
to reading array data."section has details on erasing the
entire chip.

After the system writes the autoselect command
sequence, the device enters the autoselect mode. The
system can then read autoselect codes from the internal
reqister (which is separate from the memory array) on
Q15-Q0. Standard read cycle timings apply in this mode.
Refer to the Autoselect Mode and Autoselect Command
Sequence section for more information.

ICC2 in the DC Characteristics table represents the active
current specification for the write mode. The "AC
Characteristics" section contains timing specification
table and timing diagrams for write operations.

STANDBY MODE

MX26L6420 can be set into Standby mode with two dif­ferent approaches. One is using both CE and RESET
pins and the other one is using RESET pin only .

When using both pins of CE and RESET, a CMOS
Standby mode is achieved with both pins held at Vcc ±

0.3V . Under this condition, the current consumed is less
than 50uA (typ.). If both of the CE and RESET are held
at VIH, b ut not within the range of VCC ± 0.3V , the de vice
will still be in the standby mode, but the standby currect
will be larger. During Auto Algorithm operation, Vcc ac­tive current (Icc2) is required even CE = "H" until the
operation is complated. The de vice can be read with stan­dard access time (tCE) from either of these standby
modes.

When using only RESET, a CMOS standby mode is
achieved with RESET input held at Vss ± 0.3V, Under
this condition the current is consumed less than 50uA
(typ.). Once the RESET pin is taken high,the device is
back to active without recovery delay.

In the standby mode the outputs are in the high imped­ance state, independent of the OE input.

MX26L6420 is capable to provide the Automatic Standby
Mode to restrain power consumption during read-out of
data. This mode can be used eff ectively with an applica­tion requested low power consumption such as handy
terminals.

To active this mode, MX26L6420 automatically switch
themselves to low power mode when MX26L6420 ad­dresses remain stable during access time of tACC+30ns.
It is not necessary to control CE, WE, and OE on the
mode. Under the mode, the current consumed is typi­cally 50uA (CMOS level).

OUTPUT DISABLE

With the OE input at a logic high level (VIH), output from
the devices are disabled. This will cause the output pins
to be in a high impedance state.

P/N:PM0823

REV. 0.5, JAN. 29, 2002

7

MX26L6420

RESET OPERATION

The RESET pin provides a hardware method of resetting
the device to reading arra y data. When the RESET pin is
driven low for at least a period of tRP, the device
immediately terminates any operation in progress,
tristates all output pins, and ignores all read/write
commands for the duration of the RESET pluse. The
device also resets the internal state machine to reading
array data. The operation that was interrupted should be
reinitated once the device is ready to accept another
command sequence, to ensure data integrity

Current is reduced for the duration of the RESET pulse.
When RESET is held at VSS±0.3V, the device draws
CMOS standby current (ICC4). If RESET is held at VIL
but not within VSS±0.3V, the standby current will be
greater.

The RESET pin may be tied to system reset circuitry . A
system reset would that also reset the MTP EPROM.

Refer to the AC Characteristics tables for RESET
parameters and to Figure 14 for the timing diagram.

SILICON ID READ OPERATION

Table 3

VCC / VI/O V oltage Range

Part No. VCC=2.7V to 3.6VVCC=2.7V to 3.6V

VI/O=2.7V to 3.6VVI/O=1.65V to 2.6V

MX26L6420-90 90ns 100ns
MX26L6420-12 120ns 130ns

Notes: T ypical v alues measured at VCC=2.7V to 3.6V,

VI/O=2.7V to 3.6V

DATA PROTECTION

The MX26L6420 is designed to offer protection against
accidental erasure or programming caused by spurious
system level signals that may exist during power transi­tion. During power up the device automatically resets
the state machine in the Read mode. In addition, with
its control register architecture, alteration of the memory
contents only occurs after successful completion of spe­cific command sequences. The device also incorporates
several features to prevent inadvertent write cycles re­sulting from VCC pow er-up and power-down transition or
system noise.

MTP EPROM are intended for use in applications where
the local CPU alters memory contents. As such, manu­facturer and device codes must be accessible while the
device resides in the target system. EPROM program­mers typically access signature codes by raising A9 to
a high voltage. How ever , multiple xing high voltage onto
address lines is not generally desired system design prac­tice.

MX26L6420 provides hardware method to access the
silicon ID read operation. Which method requires VID on
A9 pin, VIL on CE, OE, A6, and A1 pins. Which apply
VIL on A0 pin, the device will output MXIC's manufac­ture code of C2H. Which apply VIH on A0 pin, the device
will output MX26L6420 device code of 22FCH.

VI/O PIN OPERATION

MX26L6420 is capable to provide the I/O prower supply
(VI/O) pin to control Input/Output voltage levels of the
device. The data outputs and voltage tolerated at its data
input is determined by the voltage on the VI/O pin. This
device is allows to operate in 1.8V or 3V system as re­quired.

SECURED SILICON SECTOR

The MX26L6420 features a Flash memory region where
the system may access through a command sequence
to create a permant part identification as so called Elec­tronic Serial Number (ESN) in the device. Once this re­gion is programmed, any further modification on the re­gion is impossible. The secured silicon sector is a 512
words in length, and uses a Secured Silicon Sector Indi­cator Bit (Q7) to indicate whether or not the Secured
Silicon Sector is locked when shipped from the f actory.
This bit is permanently set at the factory and cannot be
changed, which prevent duplication of a factory locked
part. This ensures the security of the ESN once the prod­uct is shipped to the field.

The MX26L6420 offers the device with Secured Silicon
Sector either factory locked or custor lockab le. The fac­tory-locked version is always protected when shipped
from the factory , and has the Secured Silicon Sector
Indicator Bit permanently set to a "1". The customer­lockable version is shipped with the Secured Silicon
Sector unprotected, allowing customer to utilize that sec­tor in any form they pref er . The customer-loc kable v er-

P/N:PM0823

REV. 0.5, JAN. 29, 2002

8

MX26L6420

sion has the secured sector Indicator Bit permanently
set to a "0". Therefore, the Secured Silicon Sector Indi­cator Bit permanently set to a "0". Therefore, the Second
Silicon Sector Indicator Bit prevents customer, lockable
device from being used to replace devices that are fac­tory locked.

The system access the Secured Silicon Sector through
a command sequence (refer to "Enter Secured Silicon/
Exit Secured Silicon Sector command Sequence). After
the system has written the Enter Secured Silicon Sector
command sequence, it may read the Secured Silicon
Sector by using the address normally occupied by the
address 000000h-0001FFh. This mode of operation con­tinues until the system issues the Exit Secured Silicon
Sector command sequence, or until power is removed
from the device. On power-up, or following a hardware
reset, the device rever ts to sending command to ad­dress 000000h-0001FFFh.

LOW VCC WRITE INHIBIT

When VCC is less than VLKO the device does not ac­cept any write cycles. This protects dataduring VCC
power-up and power-do wn. The command register and
all internal program/erase circuits are disabled, and the
device resets. Subsequent writes are ignored until VCC
is greater thanVLK O. The system must provide the proper
signals to the control pins to prevent unintentional write
when VCC is greater than VLK O.

FACTORY LOCKED:Secured Silicon Sector
Programmed and Protected At the Factory

In device with an ESN, the Secured Silicon Sector is
protected when the device is shipped from the factory.
The Secured Silicon Sector cannot be modified in any
way . A f actory locked device has an 8-word random ESN
at address 000000h-000007h.

CUSTOMER LOCKABLE:Secured Silicon
Sector NOT Programmed or Protected At the
Factory

As an alternative to the factory-locked version, the device
may be ordered such that the customer may program
and protect the 512-word Secured Silicon Sector.
Programming and protecting the Secured Silicon Sector
must be used with caution since, once protected, there
is no procedure available for unprotecting the Secured
Silicon Sector area and none of the bits in the Secured
Silicon Sector memory space can be modified in any
way.

The Secured Silicon Sector area can be protected using
the following procedures:

Write the three-cycle Enter Secured Silicon Sector Region
command sequence. This allows in-system protection
of the Secured Silicon Sector without raising any device
pin to a high voltage. Note that method is only applicable
to the Secured Silicon Sector.

WRITE PULSE "GLITCH" PROTECTION

Noise pulses of less than 5ns(typical) on CE or WE will
not initiate a write cycle.

LOGICAL INHIBIT

Writing is inhibited by holding any one of OE = VIL, CE =
VIH or WE = VIH. To initiate a wr ite cycle CE and WE
must be a logical zero while OE is a logical one.

POWER-UP SEQUENCE

The MX26L6420 powers up in the Read only mode. In
addition, the memory contents may only be altered after
successful completion of the predefined command se­quences.

P/N:PM0823

Once the Secured Silicon Sector is programmed, locked
and verified, the system must write the Exit Secured
Silicon Sector Region command sequence to return to
reading and writing the remainder of the array .

REV. 0.5, JAN. 29, 2002

9

SOFTWARE COMMAND DEFINTIONS

MX26L6420

Device operations are selected by writing specific ad-

will reset the device(when applicable).

dress and data sequences into the command register.
Writing incorrect address and data values or writing them
in the improper sequence will reset the device to the
read mode. Table 4 defines the valid register command

All addresses are latched on the falling edge of WE or
CE, whichever happens later . All data are latched on ris­ing edge of WE or CE, whiche ver happens first.

sequences. Either of the two reset command sequences

TABLE4. MX26L6420 COMMAND DEFINITIONS

First Bus Second Bus Third Bus Fourth Bus Fifth Bus Sixth Bus

Command Bus Cycle Cycle Cycle Cycle Cycle Cycle

Cycle Addr Data Addr Data Addr Data Addr Data Addr Data Addr Data
Read(Note 5) 1 RA RD
Reset(Note 6) 1 XXX F0
Autoselect(Note 7)
Manufacturer ID 4 555 AA 2AA 55 555 90 X00 C2
Device ID 4 555 AA 2AA 55 555 90 X01 22FC
Secured Sector 4 55 5 AA 2AA 55 555 90 x0 3 see
Factory Protect Note9
Enter Secured Silicon 3 55 5 AA 2AA 55 5 55 88
Sector
Exit Secured Silicon 4 55 5 AA 2AA 55 5 55 9 0 xxx 00
Sector
Porgram 4 555 AA 2AA 55 5 55 A0 PA PD
Chip Erase 6 55 5 AA 2 AA 5 5 55 5 8 0 55 5 AA 2AA 55 5 55 10

Legend:
X=Don't care
RA=Address of the memory location to be read.

PD=Data to be programmed at location PA. Data is

latched on the rising edge of WE or CE pulse.
RD=Data read from location RA during read operation.
P A=Address of the memory location to be programmed.
Addresses are latched on the falling edge of the WE or
CE pulse.

Notes:

1.See Table 1 for descriptions of bus operations.

2.All values are in hexadecimal.

3.Except when reading array or autoselect data, all bus cycles are write operation.

4.Address bits are don't care for unlock and command cycles, e xcept when PA is required.

5.No unlock or command cycles required when device is in read mode.

6.The Reset command is required to return to the read mode when the device is in the autoselect mode or if Q5 goes

high.

7.The fourth cycle of the autoselect command sequence is a read cycle.

8.In the third and fourth cycles of the command sequence, set A21=0.

8.Command is valid when device is ready to read array data or when device is in autoselect mode.

9.The data is 88h for factory locked and 08h for non-factory locked.

P/N:PM0823

10

REV. 0.5, JAN. 29, 2002

MX26L6420

READING ARRAY DATA

The device is automatically set to reading array data
after device power-up. No commands are required to
retrieve data. The device is also ready to read arra y data
after completing an Automatic Program or Automatic
Erase algorithm.

The system must issue the reset command to re-en­able the device for reading array data if Q5 goes high, or
while in the autoselect mode. See the "Reset Command"
section, next.

RESET COMMAND

Writing the reset command to the device resets the
device to reading array data. Address bits are don't care
for this command.

The reset command may be written between the se­quence cycles in an erase command sequence before
erasing begins. This resets the device to reading array
data. Once erasure begins, however, the device ignores
reset commands until the operation is complete.

The reset command may be written between the se­quence cycles in a program command sequence before
programming begins. This resets the device to reading
array data. Once programming begins ,howe ver , the device
ignores reset commands until the operation is complete.

by writing two unlock cycles, followed by the SILICON

ID READ command. The device then enters the SILICON

ID READ mode, and the system may read at any address

any number of times, without init iating another command

sequence. A read cycle at address XX00h retrieves the

manufacturer code. A read cycle at address XX01h re-

turns the device code.

The system must write the reset command to exit the

autoselect mode and return to reading array data.

WORD PROGRAM COMMAND SEQUENCE

The command sequence requires four bus cycles, and

is initiated by writing two unlock write cycles, followed

by the program set-up command. The program address

and data are written next, which in turn initiate the

Embedded Program algorithm. The system is

to provide further controls or timings. The device

automatically generates the program pulses and verifies

the programmed cell margin. Table 4 shows the address

and data requirements for the byte program command

sequence.

When the Embedded Program algorithm is complete, the

device then returns to reading array data and addresses

are no longer latched. The system can determine the

status of the program operation by using Q7, Q6. See

"Write Operation Status" for information on these status

bits.

not required

The reset command may be written between the se­quence cycles in an SILICON ID READ command
sequence. Once in the SILICON ID READ mode, the
reset command
data.

If Q5 goes high during a program or erase operation,
writing the reset command returns the device to reading
array data.

must be written to return to reading array

SILICON ID READ COMMAND SEQUENCE

The SILICON ID READ command sequence allows the
host system to access the manufacturer and devices
codes, and determine whether or not. Table 4 shows the
address and data requirements. This method is an
alternative to that shown in Table 1, which is intended for
EPROM programmers and requires VID on address bit
A9.

The SILICON ID READ command sequence is initiated

P/N:PM0823

Any commands written to the device during the Em-

bedded Program Algorithm are ignored. Note that a

hardware reset immediately terminates the programming

operation. The Word Program command sequence should

be reinitiated once the device has reset to reading array

data, to ensure data integrity.

Programming is allowed in any sequence. A bit cannot

be programmed from a "0" back to a "1". Cause the Data

Polling algorithm to indicate the operation w as successful.

However, a succeeding read will show that the data is

still "0". Only erase operations can convert a "0" to a

"1".

REV. 0.5, JAN. 29, 2002

11

MX26L6420

ACCELERATED PROGRAM OPERATIONS

The device offers accelerated program operations through
the ACC pin. When the system asserts VHH on the ACC
pin, the device automatically bypass the two "Unlock"
write cycle. The device uses the higher voltage on the
ACC pin to accelerate the operation. Note that the ACC
pin must not be at VHH any operation other than accelerated
programming, or device damage may result.

SETUP AUTOMATIC CHIP ERASE

Chip erase is a six-bus cycle operation. There are two
"unlock" write cycles. These are f ollowed b y writing the
"set-up" command 80H. Two more "unlock" write cycles
are then followed by the chip erase command 10H.

The MX26L6420 contains a Silicon-ID-Read operation to
supplement traditional PROM programming methodology.
The operation is initiated by writing the read silicon ID
command sequence into the command register. Follo w­ing the command write, a read cycle with A6=VIL,
A1=VIL, A0=VIL retrieves the manufacturer code of C2H.
A read cycle with A6=VIL, A1=VIL, A0=VIH returns the
device code of 22FCH for MX26L6420.

AUTOMATIC CHIP ERASE COMMAND

The device does not require the system to preprogram

prior to erase. The A utomatic Erase algorithm automati-

cally preprograms and verifies the entire memory for an

all zero data pattern prior to electrical erase. The system

is not required to provide any controls or timings during

these operations. Table 4 shows the address and data

requirements for the chip erase command sequence.

Any commands written to the chip during the Automatic

Erase algorithm are ignored. Note that a hardware reset

during the chip erase operation immediately terminates

the operation. The Chip Erase command sequence should

be reinitiated once the device has returned to reading

array data, to ensure data integrity.

The system can determine the status of the erase op-

eration by using Q7, Q6. See "Write Operation Status"

for inf ormation on these status bits. When the Automatic

Erase algorithm is complete, the device returns to read-

ing array data and addresses are no longer latched.

Figure 5 illustrates the algorithm for the erase opera-

tion.See the Erase/Program Operations tables in "AC

Characteristics" for parameters, and to Figure 4 for tim-

ing diagrams.

TABLE 5. SILICON ID CODE

Pins A0 A1 A6 Q15 Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q0 Code(Hex)

|
Q8

Manufacture code VIL VIL VIL 00 H 1 1 0 0 001000C2H
Device code for MX26L6420 VIH VIL VIL 22 H 1 1 1 1 111022FCH

P/N:PM0823

12

REV. 0.5, JAN. 29, 2002