AMD Am28F020A Service Manual

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FINAL

Am28F020A

2 Megabit (256 K x 8-Bit) CMOS 12.0 Volt, Bulk Erase Flash Memory with Embedded Algorithms

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DISTINCTIVE CHARACTERISTICS

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High performance

— Access times as fast as 70 ns

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CMOS low power consumption

— 30 mA max imum active current — 100 µA maximum standby current — No data retention power consumption

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Compatible with JEDEC-standard byte-wide 32-pin EPROM pinouts

— 32-pin PDIP — 32-pin PLCC — 32-pin TSOP

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100,000 write/erase cycles minimum

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Write and erase voltage 12.0 V ±5%

Latch-up protected to 100 mA from –1 V to V

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Embedded Erase Electrical Bulk Chip Erase

— Five seconds typical chip erase, including

pre-programming

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Embedded Program

— 14 µs typical byte program, including time-out — 4 seconds typical chip program

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Command regist er architecture for microprocessor/microcontroller compatible write interface

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On-chi p add r es s and dat a latches

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Advanced CMOS flash memory technology

— Low cost single transistor memory cell

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Embed ded al gori thms f or com plet ely self -ti med write /er as e op er a tio n s

+1 V

GENERAL DESCRIPTION

The Am 28F02 0A is a 2 Mega bit F lash me mor y orga nize d as 25 6 Kb y tes of 8 bit s ea ch. AM D’s Flash memories offer the most cost-effective and reliable read/ write non-volat ile random access memory. The Am28F020A is packaged in 32-pin PDIP, PLCC, and TSOP v ers ions . It i s des ign ed to be repr ogr amme d and erased in-system or in standard EPROM programmers. The Am28F020A is erased when shipped from the factory.

The standard Am28F020A offers access times of as fast as 70 ns, allow ing h igh s peed m icr oproc esso rs to operate without wait states. To eliminate bus contention, the device has separate chip enable (CE#) and output enable (OE#) controls.

AMD’s Flash memories augment EPROM funct ionality with i n-circuit elec trical e rasure and programming. The Am28F020A uses a command register to manage this functionality. The command register allows for 100% TTL level control inputs and fixed power supply levels during erase and programming, while maintaining maximum EPROM compatibility.

The Am28F020A is compatible with the AMD Am28F256A, Am28F512A, and Am28F010A Flash memor ies. A ll devices in the Am28Fx xx family follow the JEDEC 32-pin pinout standard. In addition, all

devices within this family that offer Embedded Algorithms use the same command set. This offers designers the flexibility to retain the same device footprint and command set, at any density between 256 Kbits and 2 Mbits.

AMD’s Flash technology reliably stores memory contents even after 100,000 erase and program cycles. The AMD cell is designed to optimize the erase and programming mechanisms. In addition, the combination of advanced tunnel oxide processing and low internal ele ctric fiel ds f or er ase an d prog ra mming operations produce s reliab le cyc ling. The Am28F0 20A uses a 12.0±5% VPP supply in put to p erfor m the e rase an d programming functions.

The highest degree of latch-up protection is achieved with AMD’s prop r ietary non -e pi pr oc e ss. Lat ch- up pro tection is provided for stresses up to 100 mA on address and data pins from –1 V to VCC +1 V.

AMD’s Flash technology combines years of EPROM and EEPROM experience to produce the highest levels of quality, reliability, and cost effectiveness. Th e Am28F0 20A elec trica lly era ses a ll bits simult ane ously using Fowler-Nordheim t unneling. The bytes are programmed one byte at a time using the EPROM programming mechanism of hot electron injection.

Publication# Issu e Date:

Rev: DAmendment/

17502

January 1998

Embedded Program

The Am28F020A is byte programmable using the Embedde d P ro gram algorithm, whi c h do es no t req uir e the system to tim e- out o r verif y th e da ta progra mmed . The typi cal r oom te mper at ure pr og ram ming time of this device is four seconds.

Comparing Embedded Algorithms with Flasherase and Flashrite Algorithms

Embedded Erase

The entire device is bulk erased using the Embedded Erase al gorithm , which au tomaticall y program s the entire array prior to electrical erase. The timing and verification of electrical erase are controlled internal to the devi ce . Typical er asu re tim e at ro om te mper at ure is fiv e seconds, including preprogramming.

Embedded Programming Algorithm vs. Flashrite Programming Algorithm

Embedded Erase Algorithm vs. Flasherase Erase Algorithm

Am28F020A with

Embedded Algorithms

AMD’s Embedded Programming algorithm requires the user to only write a program set-up command and a program command (program data and address). The device automatically times the programming pulse width, verifies the programming, and counts the number of sequences. A status bit, Data# Polling, provides the user with the programming operation status.

AMD’s Embedded Erase algorithm requires the user to only write an erase setup command and erase command. The device automatically pre-programs and verifies the entire array. The device then automatically times the erase pulse width, verifies the erase operation, and counts the number of sequences. A status bit, Data# Polling, provides the user with the erase operation status.

Am28F020 using AMD Flashrite

and Flasherase Algorithms

The Flashrite Programming algorithm requires the user to write a program set-up command, a program command, (program data and address), and a program verify command, followed by a read and compare operation. The user is required to time the programming pulse width in order to issue the program verify command. An integrated stop timer prevents any possibility of overprogramming.

Upon completion of this sequence, the data is read back from the device and compared by the user with the data intended to be written; if there is not a match, the sequence is repeated until there is a match or the sequence has been repeated 25 times.

The Flasherase Erase algorithm requires the device to be completely programmed prior to executing an erase command.

To invoke the erase operation, the user writes an erase set-up command, an erase command, and an erase verify command. The user is required to time the erase pulse width in order to issue the erase verify command. An integrated stop timer prevents any possibility of overerasure.

Upon completion of this sequence, the data is read back from the device and compared by the user with erased data. If there is not a match, the sequence is repeated until there is a match or the sequence has been repeated 1,000 times.

Commands are written to the c ommand reg ister u si ng standard microprocessor write timings. Register contents serve as input to an internal state-machine, which controls the erase and programming cir cuitry. During write cycles, the command register internally latches addresses and data needed for the programming and erase operations. For system design simplification, the Am28F010A is designed to support

either WE# or CE# controlled writes. During a system write cycle, addresses are latched on the falling edge of WE# or CE#, whichever occurs last. Data is latched on the rising edge of WE# or CE#, whichever occurs first. To simplify the following discussion, the WE# pin is used as the write cycle control pin throughout the rest of this text. All setup and hold times are with respect to the WE# signal.

2 Am28F020A

PRODUCT SELECTOR GUIDE

Family Part Number Speed Options (V

= 5.0 V ± 10%)

-70 -90 -120 -150 -200

Am28F020A

Max Access Time (ns) 70 90 120 150 200 CE# (E#) Access (ns) 70 90 120 150 200 OE# (G#) Access (ns) 35 35 50 55 55

BLOCK DIAGRAM

DQ0–DQ7

WE#

CE# OE#

State

Control

Command

ister

Program

Volta

Switch

Erase

Voltage

Switch

Input/Output

Buffers

To Array

Chip Enable

Output Enable

Logic

A0–A17

Low VCC Detector

Embedded Algorithms

Program/Erase

Pulse Timer

Address Latch

Y-Decoder

X-Decoder

Data Latch

Y-Gating

2,097,152

Bit

Cell Matrix

17502D-1

Am28F020A 3

CONNECTION DIAGRAMS

A16 A15 A12

A7 A6 A5 A4 A3 A2 A1 A0

DQ0 DQ1

DQ2 V

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

PDIP

32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17

WE# (W#) A17 A14 A13 A8 A9 A11 OE# (G#) A10 CE# (E#) DQ7 DQ6

DQ5 DQ4 DQ3

17502D-2

A7 A6 A5

A4 A3 A2 A1 A0

DQ0

5 6

8 9 10

11 12 13

A12

DQ1

DQ2

PLCC

A16

A15

VSS

DQ3

VPP

DQ4

WE# (W#)

VCC

31 30

19 2016

DQ5

A17

29 28 27

26 25 24 23 22 21

DQ6

A14 A13

A9 A11 OE# (G#)

A10 CE# (E#) DQ7

17502D-3

Note: Pin 1 is marked for orientation.

4 Am28F020A

CONNECTION DIAGRAMS (Contin ued)

A11

A8 A13 A14 A17

WE#

A16 A15 A12

OE#

A10

CE#

D7 D6 D5 D4 D3

D2 D1 D0 A0 A1 A2 A3

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

32-Pin TSOP—Standard Pinout

32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17

OE# A10 CE# D7 D6 D5 D4 D3 V

D2 D1 D0 A0 A1 A2 A3

A11 A9 A8 A13 A14 A17 WE# V

A16 A15 A12 A7 A6 A5 A4

LOGIC SYMBOL

32-Pin TSOP—Reverse Pinout

A0–A17

DQ0–DQ7

CE# (E#) OE# (G#)

WE# (W#)

17502D-4

17502D-5

Am28F020A 5

ORDERIN G IN FOR MATION Standard Products

AMD standard pro ducts are avail able in several packages and operating rang es. The order ing number (Va lid Combinatio n) is formed by a combination of the following:

AM28F020A -70 J C

DEVICE NUMBER/DESCRIPTION

Am28F020A 2 Megabit (256 K x 8-Bit) CMOS Flash Memory with Embedded Algorithms

OPTIONAL PROCESSING

Blank = Standard Processing B = Burn-In

Contact an AMD representative for more information.

TEMPERATURE RANGE

C = Commercial (0°C to +70°C) I = Industrial (–40°C to +85°C) E = Extended (–55°C to +125°C)

PACKAGE TYPE

P = 32-Pin Plastic DIP (PD 032) J = 32-Pin Rectangular Plastic Leaded Chip

Carrier (PL 032)

E = 32-Pin Thin Small Outline Package (TSOP)

Standard Pinout (TS 032)

F = 32-Pin Thin Small Outline Package (TSOP)

Reverse Pinout (TSR032)

SPEED OPTION

See Product Selector Guide and Valid Combinations

Valid Combinations

AM28F020A-70 AM28F020A-90 AM28F020A-120 AM28F020A-150 AM28F020A-200

PC, PI, PE,

JC, JI, JE,

EC, EI, EE,

FC, FI, FE

Valid Combinations list configurations planned to be supported in volume for this device. Consult the local AMD sales office to confirm availab ility of specific val id combination s and to check on newly released combinations.

6 Am28F020A

Valid Combinations

PIN DESCRIPTION A0–A17

Address In puts for memor y lo cations. Inte rnal la tches hold addresses during write cycles.

CE# (E#)

Chip Enable active low input activates the chip’s control logic and input buffers. Chip Enable high will deselect the device and operates the chip in stand-by mode.

DQ0–DQ7

Data Inputs during memory write cycles. Internal latches hold data during write cycles. Data Outputs during memory read cycles.

No Conn ect- corre spond ing pin i s no t conn ec ted in ternally to the die.

OE# (G#)

Output Enable active low input gates the outputs of the device th rough the da ta buffers during me mor y read cycles. Output Enable is high during command sequencing and program/erase operations.

Program voltage input. VPP must be at hi gh voltag e in order to write to the command register. The command register controls all functions required to alter the memory array contents. Memory contents cannot be altered when VPP ≤ VCC +2 V.

Po w er supp ly for de vi ce oper at ion . (5.0 V ± 5% or 10%)

Ground.

WE# (W#)

Write Enable active low input controls the write function of the command register to the memory array. The target address is latched on the falling edge of the Write Enable pulse and the appropriate data is latched on the rising edg e of t he pul se. Writ e E nabl e h igh i nhi bit s wri ting to the device.

Am28F020A 7

BASIC PRINCIPLES

The Am28FxxxA family uses 100% TTL-level control inputs to manage the command regi ster. Erase and reprogramming op erations use a fixed 12.0 V ± 5% high voltage input.

Read Only Memory

Without high VPP voltage, the device functions as a read only memory and operates like a standard EPROM. Th e control inpu ts still ma nage traditi onal read, standby, output disable, and Auto select modes.

Command Register

The command register is enabled only when high voltage is applied to the VPP pin. The erase and reprogramming operations are only accessed via the register. In addition, two-cycle commands are required for erase and reprogramming op erations. The traditional read, standby, output disable, and Auto select modes are available via the register.

The device’ s command register is written using standard microproce ssor wr ite timin gs. The register c ontrols an interna l state machine that mana ges all device operations. For system design simplification, the device is designed to support either WE# or CE# control led writes. During a system write cycle, addresses are latched on the falling edge of WE# or CE# whichever occurs last. Data is latched on the rising edge of WE# or CE# whichever occur first. To si mplify the following discussion, the WE# pin is used as t he write cycle control pin throughout the rest of this text. All setup and hold times are with respect to the WE# signal.

OVERVIEW OF ERASE/PROGRAM OPERATIONS

Embedded

AMD now makes erasure extremely simple and reliable. The Embedded Erase algorithm requires the user to only write an erase setup command and erase command. The d evice will autom atically pre-pr ogram and verify the entir e array. The device automatical ly times the erase pulse width, provides the erase verify and counts the number of sequences. A status bit, Data# Polling, provides feedback to the user as to the status of the erase operation.

Erase Algorithm

Embedded Programming Algorithm

AMD now makes programming extremely simple and reliable. The Embedded P rogramming algorith m re-

quires the user to on ly writ e a pr ogr am s etu p comma nd and a program comm and. The device automatically times the programm ing puls e width, provi des the p rogram verify and counts the number of sequences. A status bit, Data# Polling, provides feedback to the user as to the status of the programming operation.

DATA PROTECTION

The device is designed to offer protection aga inst acci dental erasure or programming ca used by spurious system level signals that may exist during power transitions . The d evice po wers up in it s r ea d onl y st at e . A ls o, with its control register architecture, alteration of the memory contents only occurs after successful completion of specific command sequences.

The device al so i ncor pora tes s everal feat ures t o pre vent inadvertent write cycles resulting from V power-up and power-down transitions or system noise.

Low VCC Write Inhibit

To avoid initiation of a write cycle during VCC power -up and power-d own, the d evice locks out wr ite cycl es for VCC < V ages). When VCC < V abled, all internal program/erase circuits are disabled, and the device resets to the read mode. The device ignores all writes until V that the control pins are in the correct logic state when VCC > V

(see DC characteristics section for volt-

LKO

to prevent unintentional writes.

LKO

, the command register is dis-

LKO

> V

. The user m ust ensure

LKO

Write Pulse “Glitch” Protection

Noise pulses of less than 10 ns (typical) on OE#, 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 wri te cycle CE# and WE# must be a logical zero while OE# is a logical one.

Power-Up Write Inhibit

Power-up of th e device with W E# = CE # = VIL and OE# = VIH will not a ccept comman ds on the r ising edge of WE#. The internal state ma chine is automatically reset to the read mode on power-up.

8 Am28F020A

FUNCTIONAL DESCRIPTION Description Of User Modes

Table 1. Am28F0 20A Device Bus Operations (Notes 7 and 8)

Read-Only

Read/Write

Operation

(E#)

Read V Standby V Output Disable V Auto-select Manufacturer

Code (Note 2) Auto-select Device

Code (Note 2) Read V

Standby (Note 5) V Output Disable V Write V

(G#)

V V

(W#)

XXV

(Note 1) A0 A9 I/O

PPL

PPH

A0 A9 D

X X HIGH Z X X HIGH Z

(Note 3)

A0 A9

X X HIGH Z X X HIGH Z

A0 A9

Legend:

X = Don’t care, where Don’t Care is either V

of V

. 0 V < An < VCC + 2 V, (normal TTL or CMOS input levels, where n = 0 or 9).

PPH

or VIH levels. V

= VPP < VCC + 2 V. See DC Characteristics for voltage levels

PPL

Notes:

1. V

may be grounded, connected with a resistor to ground, or < VCC + 2.0 V. V

PPL

the device. Refer to the DC characteristics. When VPP = V

, memory contents can be read but not written or erased.

PPL

is the programming voltage specified for

PPH

2. Manufacturer and device codes may also be accessed via a command register write sequence. Refer to Table 2.

3. 11.5 < V

4. Read operation with V

5. With V

6. Refer to Table 3 for valid D

7. All inputs are Don’t Care unless otherwise stated, where Don’t Care is either V addresses except A

8. If V

< 13.0 V. Minimum VID rise time and fall time (between 0 and VID voltages) is 500 ns.

= V

at high voltage, the standby current is ICC + IPP (standby).

and A0 must be held at VIL.

1.0 Volt, the voltage difference between VPP and VCC should not exceed 10.0 volts. Also, the Am28F256 has a VPP

≤

may access array data or the Auto select codes.

PPH

during a write operation.

or VIH levels. In the Auto select mode all

rise time and fall time specification of 500 ns minimum.

OUT

CODE

(01h)

CODE

(29h) D

OUT

(Note 4)

(Note 6)

Am28F020A 9

READ-ONLY MODE

When VPP is less than V is inactive. The device can either read array or autoselect data, or be standby mode.

+ 2 V, the comm and regis ter

Read

The device f unc t ion s as a r ea d o nly m em ory wh en V < V

+ 2 V . The de v ice ha s tw o con tro l fu ncti ons . Bo th

must be satisfied in order to output data. CE# controls power to the d evice. This pin sh ould be used for specific device selection. OE# controls the device outputs and shou ld be used to gate data to the output pin s if a device is selected.

Address access time t

is equal to the delay from

ACC

stable addresses to valid ou tput data. Th e ch i p en able access time tCE is the delay from stable addresses and stable CE# to valid data at the output pins. The output enable access time is the delay from the falling edge of OE# to valid dat a at the o utp ut pins (assumi n g th e ad dresses have been stable at least t

ACC

- tOE).

Standby Mode

The device has two standby modes. The CMOS standby mode (CE# input held at V sumes less than 100 µA of curren t. TTL standby mode (CE# is held at VIH) reduces the current requirements to less than 1 m A . When in the stan dby mo de the outputs are in a high impedance state, independent of the OE# input.

If the device is deselected during eras ure, programming, or p rogram/erase verificati on, the device will draw active current until the operation is terminated.

± 0.5 V), con-

Output Dis a ble

Output from the device is disabled when OE# is at a logic high level. When disabled, output pins are in a high impedance state.

Auto Select

Flash memories can be programmed in-system or in a standard PROM programmer. The device may be soldered to the circuit board upon receipt of shipment and programmed in-system. Alternatively, the device may initially be programmed in a PROM programmer pr ior to soldering the device to the board.

The Auto se l e ct m od e allows th e r e ad in g ou t of a bin a ry code from the device that will identify its manufacturer and type. This mode is intended for the purpose of automatically matching the device to be programmed with its corresponding pr ogramming algorithm . This mode is functio nal ove r the entir e temperat ure range of the devi ce.

Programming In A PROM Programmer

To activate thi s mode, the programmin g equipm ent must force VID (11.5 V to 13.0 V ) on addre ss A9 . Two identi fie r b yte s ma y th en be seq uence d fr om th e de vi ce outputs by toggling address A0 from VIL to VIH. All other address lines must be held at VIL, and VPP must be less than or equal to VCC + 2.0 V while using this Auto select mode. Byte 0 (A0 = VIL) repr esen ts th e man uf acturer code and byte 1 (A0 = VIH) the device identifier code. For the device the two bytes are given in the table 2 of the device data sheet. All identifiers for manufacturer and device codes will exhibit o dd parity with th e MSB (DQ7) defined as the parity bit.

Table 2. (Am28F020A Auto Select Code

Type A0

Manufacturer Code V Device Code V

10 Am28F020A

Code

(HEX)

01 29

ERASE, PROGRAM, AND READ MODE

When VPP is equal to 12.0 V ± 5%, the command register is active. All fu nctions ar e available. Tha t is, the device can program, erase, read array or autoselect data, or be standby mode.

Write Operations

High voltage must be applied to the VPP pin in orde r to activate the command register. Data written to the register serves as input to the internal state machine. The output of the state machine determines the operational function of the device.

The command register does not occupy an addressable memory locat ion. The re giste r is a latch t hat stor es the com mand , along with th e addr ess and data in formation needed to execute the command. The register is written by bringing WE# and CE# to VIL, while OE# is at VIH. Addresses are latched on the falling edge of WE#, while data is latched on the rising edge of the WE# pulse. Standard microprocessor write timings are used.

The device requires the OE# pin to be VIH for write operations. This condition eliminates the possibility for bus contention during programming operations. In order to write, OE# must be VIH, and CE# and WE# must be VIL. If any pin is not in the correct state a write command will not be executed.

Refer to AC Write Characteristics and the Erase/Programming Waveforms for specific timing parameters.

Command Definitions

The contents of the command register default to 00h (Read Mode) in the absence of high v oltage appl ied to the VPP pin. The d evice op erates as a read only memory. High voltage on the VPP pin enables the command register. Device operations are selected by writing specific dat a code s into t he command regi st er . Table 3 in the de vice d ata sheet defi nes thes e regi ster commands.

Read Command

Memor y conte nts can be acces sed via th e read com mand when VPP is high. To read from the device, write 00h into the command register. Standard microprocessor read cycles access data from the memory. The device will remain in the read mode until the command register contents are altered.

The comma nd register defaults to 00h (r ead mode) upon VPP power -up . The 00h (Rea d Mode ) regis ter default helps ensure that inadvertent alteration of the memory contents does not occur during the VPP power transition. Refer to the AC Read Characteristics and Waveform s for the spec ifi c timi n g para m ete rs.

Table 3. Am28F020A Command Definitions

First Bus Cycle Second Bus Cycle

Operation

Command

Read Memory (Note 4) Write X 00h/FFh Read RA RD Read Auto select Write X 80h or 90h Read 00h/01h 01h/29h Embedded Erase Set-up/

Embedded Erase Embedded Program Set-up/

Embedded Program Reset (Note 4) Write X 00h/FFh Write X 00h/FFh

Notes:

1. Bus operations are defined in Table 1.

2. RA = Address of the memory location to be read. PA = Address of the memory location to be programmed. Addresses are latched on the falling edge of the WE X = Don’t care.

3. RD = Data read from location RA during read operation. PD = Data to be programmed at location PA. Data latched on the rising edge of WE

4. Please reference Reset Command section.

(Note 1)

Write X 30h Write X 30h

Write X 10h or 50h Write PA PD

Address

(Note 2)

pulse.

Data

(Note 3)

Operation

(Note 1)

Address

Note 2)

Data

(Note 3)

Am28F020A 11

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