NexFlash Technologies, Inc.

PRELIMINARY

NXSF006E-0801

08/22/01 ©

NX26F080A
NX26F160

8M-BIT AND 16M-BIT SERIAL FLASH MEMORY
WITH 2-PIN NXS INTERFACE

FEATURES

· Tailored for Portable and Mobile Media-Storage

Ideal for portable/mobile applications that transfer

and store data, audio, or images

Removable Serial Flash Module package option

NexFlash TM Non-volatile Memory Technology

Patented Single-Transistor EEPROM Cell
High-density, cost-effective, low-voltage/power
10K/100K endurance, ten years data retention

· Flash Memory for Battery-Operation

Single 5V or 3V supply for Read, Erase/Write
Icc 15 mA active with 1

µA standby power

5 ms Erase/Write times for efficient battery use

· 8M-bits or 16M-bits of

NexFlash Serial Memory

2,048 or 4,096 sectors of 536 bytes each
Simple commands: Reset, Read, Write,

Ready/Busy

No pre-erase required, auto-erases before write

· Two-pin NXS Serial Interface

Saves Microcontroller-pins, simplifies PCB layout,

low switching noise compared to parallel Flash

Supports clock operation as fast as 16 MHz
Multi-device cascading, up to 16 devices

· Development Tools and Accessories

NX-SFK-NXS Serial Flash Development Kit

Description

The

NexFlashTM NX26F080A and NX26F160 Serial Flash

Memories are tailored for portable/mobile media-storage
applications that transfer and store data, audio and images.
Manufactured using

NexFlash's patented single transistor

EEPROM memory cell, the NX26F080A and NX26F160
provide a high-density, low-voltage, low-power, and cost
effective solution for battery-operated nonvolatile data stor-
age requirements. The NX26F080A and NX26F160 can
operate with a single 5V or 3V supply for Read, Write, and
Erase. Power consumption is very low due to

µA standby

current and fast Erase/Write performance (as fast as 5 ms
per sector) that minimizes power-on time, resulting in a
highly efficient energy-per-transfer ratio. The NX26F080A

PRELIMINARY

AUGUST 1999

and NX26F160 offer 8M-bits and 16M-bits of Flash memory
organized in sectors of 536 bytes each. Each sector is
individually addressable through basic commands or con-
trol functions such as Reset, Read, Erase/Write, and
Ready/Busy. The NXS (

NexFlash Serial) 2-wire serial

interface is ideal for use with microcontrollers since it only
requires two pins. This leaves pins normally used for parallel
Flash free for other uses. The NXS interface supports clock
rates as fast as 16 MHz and allows for multi-device cascading
of up to 16 devices. It also simplifies PC-board layout and
generates less transient noise than parallel devices. Devel-
opment is supported with the NexFlash Serial Flash
Development Kit.

This document contains PRELIMINARY INFORMATION. NexFlash reserves the right to make changes to its product at any time without notice in order to improve design and supply the
best possible product. We assume no responsibility for any errors which may appear in this publication.

NX26F080A
NX26F160

NexFlash Technologies, Inc.

PRELIMINARY

NXSF006E-0801

08/22/01 ©

Pin Descriptions

Package Types
The NX26F080A and NX26F160 is available in a 24/28-pin
TSOP (Type II) package (Figure 1 and Table 1) or a
removable Serial Flash Module (see NX25Mxxx/NX26Mxxx
Serial Flash Module data sheet for further information).

Power Supply Pins (Vcc and GND)
The NX26F080A and NX26F160 support single power supply
Read, Erase, and Write operations available in 5V and 3V Vcc
versions. Active power requirements are as low as 15 mA for
3V versions with standby current in the 1

µA range.

NXS Serial Interface Pins (SCK and SIO)
The 2-wire NXS (NexFlash Serial) interface includes a
Clock Input pin (SCK) and a single bidirectional I/O pin for
data (SIO). All data to or from the SIO pin is clocked
relative to the rising edge of SCK. The 2-wire NXS serial
interface makes the NX26F080A and NX26F160 an ideal
solution for removable non-volatile storage. A simple edge
connector or cable/connector with four contacts (SCK,
SIO, Vcc, and GND) can support communications with
space efficiency and reliability. The NXS interface can
operate at clock rates up to 16 MHz for 5V versions.

Device Address Pins (A0, A1, A2, A3)
There is no active chip select on the NX26F080A and
NX26F160. Instead, four static device address pins
(A0, A1, A2, and A3) are provided for decoding from one to
16 possible devices (Figure 2). This allows up to 16MB
(using an NX26F080A device) or 32MB (using an NX26F160
device) to be addressed via a single 2-wire NXS interface.
The static address pins (A0-A3) must be tied high or low to
match the device address field (DA3-DA0) in the sector
Read and Erase/Write instruction sequences.

No Connect Pins (N/C)
The NX26F080A and NX26F160 uses only a few signal
pins. As a result, the TSOP package has numerous
no connects (NC) that have no electrical contact to the die.

Table 1. Pin Descriptions

A0, A1, A2, A3

Device Address

SCK

Serial Clock

SIO

Serial Data I/O

Vcc

Power Supply

GND

Ground

No Connect

SCK

SIO

Vcc

GND

N/C

Figure 1. NX26F080A and NX26F160 Pin Assignments

NexFlash Technologies, Inc.

PRELIMINARY

NXSF006E-0801

08/22/01 ©

NX26F080A
NX26F160

....

NX26F080A or

NX26F160

NX26F080A or

NX26F160

NX26F080A or

NX26F160

NX26F080A or

NX26F160

U10

NX26F080A or

NX26F160

U11

NX26F080A or

NX26F160

NX26F080A or

NX26F160

NX26F080A or

NX26F160

SCK

SIO

MICROCONTROLLER / MICROPROCESSOR

DSP or ASIC

Figure 2. NX26F080A or NX26F160 Used in a Multi-device Configuration with up to 16-Devices on the 2-wire NSX

FUNCTIONAL OVERVIEW

The

NexFlash NX26F080A and NX26F160 provide up to

8M-bits or 16M-bits of non-volatile memory organized as
2,048 or 4,096 small sectors of 536 bytes (4,288 bits) each
(Figure 3). Each sector is individually addressable using
basic instruction sequences and control functions commu-
nicated through the devices 2-wire NXS interface.

Read and Erase/Write Instruction Sequences
The NX26F080A and NX26F160 have two basic instruction
sequences: Read and Erase/Write. Unlike some other
Flash technologies, the erase and write operations of the
NX26F080A and NX26F160 are performed together in one
single operation (as fast as 5 ms per sector). Thus,
pre-erase of the memory is not necessary.

Both Read and Erase/Write instructions are made up of a
series of serial bit fields that include command, sector
address, device address, and sector data. The Read
instruction sequence also allows the device to be polled for
Ready/Busy status.

Sector 0 (0000H)

4288 Bits (536 Bytes) Per Sector

Sector 1 (0001H)

Sector 2 (0002H)

Sectors 3-2045/4093

(0003-07FD/0FFDH)

Sector 2046/4094 (07FE/0FFEH)

Sector 2047/4095 (07FF/0FFFH)

Figure 3.

NexFlash's NX26F080A and NX26F160 Array

NX26F080A
NX26F160

NexFlash Technologies, Inc.

PRELIMINARY

NXSF006E-0801

08/22/01 ©

The instruction sequence format, flow charts, and clocking
diagrams for Read and Erase/Write operations are shown in
Figures 5 and 6, Figures 7 and 8, and Figures 9 and 10,
respectively. All data within an instruction sequence is
clocked on the rising edge. All instruction sequence fields are
ordered by most significant bit first (MSB). Data is erased and
written to the NX26F160 and NX26F080A memory array a full
sector (536 bytes) at a time. If all 536 bytes of a given sector
are not fully clocked into the device, the remaining byte
locations will be overwritten with indeterminate values. To
ensure the highest level of data integrity write operations
should be verified and rewritten, if needed, (see High Data
Integrity Applications).

Reset and Idle
Upon power-up and between Read and Erase/Write instruc-
tion sequences, the device's internal control logic will be
reset. This is accomplished by asserting the SCK pin low
(to V

) for greater than

RESET

. Once reset, the device enters

standby operation and will not wake-up until the next rising
edge of SCK. After an initial rising SCK occurs, the device
becomes ready for a new instruction sequence. Full active
power consumption starts after the correct device address is
decoded during a Read or Write instruction sequence. To idle
an instruction sequence between clocks, SCK must be kept
high (at V

) for as long as needed. Note that power will be in

the active state when SCK is held high.

Device Initialization
After power-up it is recommended that the device information
sector be read to electronically identify the device. The
device information format contains a device ID that identifies
the manufacturer, part number (memory size), and operating
range. It also contains a list of any restricted sectors
(see Sector Tag/Sync bytes). For a further description of the
NX26F080A and NX26F160 device information format, see
the Serial Flash Device Information Sector Application Note
SFAN-02.

As shown in Figure 6, the address for the device information
sector address is at 5000H for both the NX26F080A and
NX26F160. The device information sector is a "read-only"
sector. This assures that all device specific information,
such as the restricted sector list, is maintained and never
written over inadvertently.

For compatibility with applications that used the original
NX26F080 (non A), which does not have a separate device
information sector, a copy of the device information sector is
also provided in the last two sectors of the NX26F080A
(07FFH and 07FEH) and NX26F160 (0FFFH and 0FFEH).
Contact

NexFlash's Serial Flash applications department if

you require compatibility with the NX26F080 (non A).

Ready/Busy Status
After an Erase/Write instruction sequence has been
executed, the device will become Busy while it erases and
writes the addressed sector's memory. This period of time
will not exceed t

(~5 to 30 ms based on the specified power

supply operating voltage). During this time the device can be
tested for a Ready/Busy condition via a 16-bit status value
obtained in the Read instruction sequence. The Busy status
condition (6666H) indicates that the device has not yet
completed its write operation and will not accept read or write
instructions. The Ready status condition (9999H) indicates
that the device is available for further read or write operations.
Note that a delay time of t

(~30 µs to 100 µs depending on

the voltage version being used) is required after the first low
to high clock transition of the Ready/Busy status read.

Sector Tag/Sync Bytes
The first byte of each sector is pre-programmed during
manufacturing with a Tag/Sync value of "C9H". Although the
first byte of each sector can be changed, it is recommended
that Tag/Sync value be maintained and incorporated as part
of the application's sector formatting. The Tag/Sync values
serve two purposes. First, they provide a sync-detect that
can help verify if the instruction sequence was clocked into
the device properly. Secondly, they serve as a tag to identify
a fully functional (valid) sector. This is especially important
if "restricted sector" devices are used.

Restricted sector devices provide a more cost effective
alternative to NX26F080A or NX26F160 devices with 100%
valid sectors. Restricted sector devices have a limited
number of sectors (64 maximum. for the NX26F080A and
NX26F160) that do not meet manufacturing programming
criteria over the specified operating range. When such a
sector is detected, the first byte is tagged with a pattern other
than "C9H". In addition to individual sector tagging, all
restricted sectors for a given device are listed in the "device
information format" (see Device Initialization).

High Data Integrity Applications
Data storage applications that use Flash memory or other
non-volatile media must take into consideration the possibil-
ity of noise or other adverse system conditions that may
affect data integrity. For those applications that require higher
levels of data integrity it is a recommended practice to use
Error Correcting Code (ECC) techniques. The NexFlash
Serial Flash Development Kit provides a software routine for
a 32-bit ECC that can detect up to two bit errors and correct
one. The ECC not only minimizes problems caused by
system noise but can also extend Flash memory endurance.
For those systems without the processing power to handle
ECC algorithms, a simple "verification after write" is recom-
mended. The NexFlash Serial Flash Development Kit
software includes a simple Write/Verify routine that will
compare data written to a given sector and rewrite the sector
if the compare is not correct.

NexFlash Technologies, Inc.

PRELIMINARY

NXSF006E-0801

08/22/01 ©

NX26F080A
NX26F160

Output remaining 535 bytes

(4280 bits) of sector data

Output (Rewrite )1st byte of sector

with C9H Tag/Sync bite

Output two bytes of zeros (00 00H)

for the IS26F160

Assert CLK low for

RESET

to invoke Erase/Write Operation

and then standby operation

Output one clock to wake

device from stand-by

Call Read Sector Routine to

check Ready/Busy and Tag

Start Sector Erase/Write Routine

Return

(1)

Yes

No*

Device

Ready and Sector

Tag valid

*Set Flag and process

accordingly upon return

Output Command Sequence:

-Read command C3-C0 (0002B)

-Main Sector Address SA11-0
(000-FFFH)

-Device Address DA3-DA0
(per state of A3, A2, A1, A0 pins)

-Auxilary Address A15-A12
0H for main array

-Four reserved bytes R31-R0
(00 00 00 00H)

Figure 8. Sector Erase/Write Operation Flow Chart

Input first byte of data

(Tag/Sync) from sector

*Set Flag and process

accordingly upon return

Return

Yes

No*

Yes*

Ready?

(99 99H)

Input remaining 535 bytes of

sector data (4280 bits)

Return to write routine?

Assert CLK low for

RESET

reset device and invoke standby

Valid Sector?

(C9H)

Start Sector Read Routine

Output clock (low to high) to

wake device from standby

Input Ready/Busy Status S15-S0.

Note t

delay time is

required during status read

(See AC Timing and Figure 10)

Output Command Sequence:

-Read command C3-C0 (0001B)

-Main Sector Address SA11-0
(000-FFFH)

-Device Address DA3-DA0
(per state of A3, A2, A1, A0 pins)

-Auxilary Address A15-A12
0H for main array
5H device information sector

-Four reserved bytes R31-R0
(00 00 00 00H)

Yes

Figure 7. Sector Read Operation Flow Chart

Note:

1. To ensure higher data integrity verify each sector write with a sector read. See High Data Integrity Applications on Page 4.

NX26F080A
NX26F160

NexFlash Technologies, Inc.

PRELIMINARY

NXSF006E-0801

08/22/01 ©

ABSOLUTE MAXIMUM RATINGS

(1)

Symbol

Parameter

Conditions

Range

Unit

Vcc

Supply Voltage

0 to 7.0

, V

OUT

Voltage Applied to Any Pin

Relative to Ground

0.5 to Vcc + 0.6

STG

Storage Temperature

65 to +150

LEAD

Lead Temperature

Soldering, Ten Seconds

+300

Note:
1. This device has been designed and tested for the specified operation ranges. Proper operation outside of these levels is not

guaranteed. Exposure beyond absolute maximum ratings (listed above) may cause permanent damage

OPERATING RANGES

Symbol

Parameter

Conditions

Min

Max

Unit

Vcc

Supply Voltage

26F080A-5T-R

26M080A-5T-R

4.5

5.5

26F080A-3T-R

26M080A-3T-R

2.7

3.6

26F160-5T-R

26M160-5T-R

4.5

5.5

26F160-3T-RS1

26M160-3T-R

3.0

3.6

26F160-3T-R

2.85

3.6

Ambient Temperature,

Commercial

+70

°C

Operating

Extended

(1)

+80

°C

Industrial

(1)

+85

°C

Note:
1. Contact

NexFlash for availability of extended or industrial grade devices.

DC ELECTRICAL CHARACTERISTICS

Symbol

Parameter

Conditions

Min

Typ

Max

Unit

Input Low Voltage

0.4

V c c x 0 . 2

Input High Voltage

V c c x 0 . 6

Vcc + 0.5

Output Low Voltage

O L

= 2 mA, V

C C

= 4.5V

0.45

Output High Voltage

O H

= 400

µA, V

C C

= 4.5V

2.4

OLC

Output Low Voltage CMOS

(1)

C C

= Min, I

O L

= 10

µA

0.15

OHC

Output High Voltage CMOS

(1)

C C

= Min, I

O H

= 10

µA

C C

0.3

L I

Input Leakage

0 < V

I N

< V c c

+10

µA

I/O Leakage

0 < V

I N

< Vcc, Output Disabled

+10

µA

C C

(active)

Active Power Supply Current

(2)

C L K

8 MHz (1/t

C P

)

C C

= 4.5V to 5.5V

C C

= 2.7V to 3.6V (NX26F080A)

C C

= 2.85V to 3.6V (NX26F160)

C C S B

(standby) Standby Power Supply Current

SIO = 0V or V

C C

µA

SCK = 0V

Input Capacitance

(1)

= 25°C, V

C C

= 5V or 3V

Frequency = 1 MHz

OUT

Output Capacitance

(1)

= 25°C, V

C C

= 5V or 3V

Frequency = 1 MHz

Notes:
1. Tested on a sample basis or specified via design or characterization data.
2. The device leaves "standby" power consumption after the clock transitions from low-to-high. Full "active" power consumption

starts after the correct device address has been decoded during a sector read or write sequence.

NexFlash Technologies, Inc.

PRELIMINARY

NXSF006E-0801

08/22/01 ©

NX26F080A
NX26F160

AC ELECTRICAL CHARACTERISTICS

5V (16 MHz)

3V (8 MHz)

Symbol

Description

Min

Typ

Max

Min

Typ Max

Unit

SCK Serial Clock Period

125

, t

SCK Serial Clock High or Low Time

SCK Serial Clock Rise Time

(1)

SCK Serial Clock Fall Time

(1)

SIO Setup Time to SCK Rising Edge

100

SIO Hold Time From SCK Rising Edge

SIO Valid after SCK

(2)

115

RESET

SCK Low Duration for

1 0

µs

Valid Reset or Standby

(See Figures 9 & 10)

Read Pre-data Delay

(See Figure 9)

3 0

1 0 0

µs

Erase/Write Program Time

(3)

N X 2 6 F 0 8 0 A

1 0

m s

(See Figure 10)

N X 2 6 F 1 6 0

5 . 5

2 5

3 2

Notes:
1. Test points are 10% and 90% points for rise/fall times. All other timings are measured at the 50% point.
2. With 50 pF (8 MHz) or 30 pF (16 MHz) load SIO to GND.
3. The NX26F080A and NX26F160 are designed for Erase/Write endurances of 10K cycles. Endurance in the range of 100K

cycles can be obtained using ECC software methods like those provided in the SFK Serial Flash Development Kit.

SCK

SIO

Read

Write

CLOCK AND DATA TIMING

NexFlash Technologies, Inc.

PRELIMINARY

NXSF006E-0801

08/22/01 ©

NX26F080A
NX26F160

ORDERING INFORMATION

Size

Order Part No.

Package/Description

(2)

8M-bit

NX26F080A-3T-R

(1)

NXS, 28-pin, TSOP (Type II)

64 RS, 3V Low Voltage

8M-bit

NX26F080A-5T-R

(1)

NXS, 28-pin, TSOP (Type II)

64 RS, 5V Standard Voltage

16M-bit

NX26F160-3T-R

NXS, 28-pin, TSOP (Type II)

64 RS, 2.85V-3.6V Low Voltage

16M-bit

NX26F160-3T-RS1

NXS 28-pin, TSOP (Type II)

64 RS 3.0V-3.6V Low Voltage

16M-bit

NX26F160-5T-R

(1)

NXS, 28-pin, TSOP (Type II)

64 RS, 5V Standard Voltage

Notes:

1. Add E (Extended) or I (Industrial) after package designator (T) for alternative

temperature grades.

2. See 26Mxxx data sheet for Serial Flash Module package.

PRELIMINARY DESIGNATION

The "Preliminary" designation on an

NexFlash data sheet

indicates that the product is not fully characterized. The
specifications are subject to change and are not guaran-
teed.

NexFlash or an authorized sales representative should

be consulted for current information before using this
product.

IMPORTANT NOTICE

NexFlash reserves the right to make changes to the
products contained in this publication in order to improve
design, performance or reliability.

NexFlash assumes no

responsibility for the use of any circuits described herein,
conveys no license under any patent or other right, and
makes no representation that the circuits are free of patent
infringement. Charts and schedules contained herein
reflect representative operating parameters, and may vary
depending upon a user's specific application. While the
information in this publication has been carefully checked,
NexFlash shall not be liable for any damages arising as a
result of any error or omission.

LIFE SUPPORT POLICY

NexFlash does not recommend the use of any of its
products in life support applications where the failure or
malfunction of the product can reasonably be expected to
cause failure in the life support system or to significantly
affect its safety or effectiveness. Products are not autho-
rized for use in such applications unless

NexFlash receives

written assurances, to its satisfaction, that:

(a) the risk of injury or damage has been minimized;

(b) the user assumes all such risks; and

NexFlash is adequately protected

under the circumstances.

Trademarks:
NexFlash

is a trademark of

NexFlash Technologies, Inc.

All other marks are the property of their respective owners.

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