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Features

• Fast Read Access Time – 150 ns

• Automatic Page Write Operation

– Internal Address and Data Latches for 64 Bytes

– Internal Control Timer

• Fast Write Cycle Times

– Page Write Cycle Time: 3 ms or 10 ms Maximum

– 1 to 64-byte Page Write Operation

• Low Power Dissipation

– 50 mA Active Current

– 200 µA CMOS Standby Current

• Hardware and Software Data Protection

• DATA Polling for End of Write Detection

• High Reliability CMOS Technology

– Endurance: 10

or 10

Cycles

– Data Retention: 10 Years

• Single 5V ± 10% Supply

• CMOS and TTL Compatible Inputs and Outputs

• JEDEC Approved Byte-wide Pinout

• Full Military, Commercial, and Industrial Temperature Ranges

Description

The AT28C256 is a high-performance electrically erasable and programmable read

only memory. Its 256K of memory is organized as 32,768 words by 8 bits. Manufac-

tured with Atmel’s advanced nonvolatile CMOS technology, the device offers access

times to 150 ns with power dissipation of just 440 mW. When the device is deselected,

the CMOS standby current is less than 200 µA.

256K (32K x 8)

Paged Parallel

EEPROM

AT28C256

Rev. 0006H–12/99

Pin Configurations

Pin Name Function

A0 - A14 Addresses

Chip Enable

Output Enable

Write Enable

I/O0 - I/O7 Data Inputs/Outputs

NC No Connect

DC Don’t Connect

CERDIP, PDIP, FLATPACK,

SOIC — Top V iew

A14

A12

I/O0

I/O1

I/O2

GND

VCC

A13

A11

A10

I/O7

I/O6

I/O5

I/O4

I/O3

TSOP

Top V iew

A11

A13

VCC

A14

A12

A10

I/O7

I/O6

I/O5

I/O4

I/O3

GND

I/O2

I/O1

I/O0

LCC, PLCC

Top V iew

Note: PLCC package pins 1 and

17 are DON’T CONNECT.

I/O0

A11

A10

I/O7

I/O6

I/O1

I/O2

GND

I/O3

I/O4

I/O5

A12

A14

VCC

A13

(continued)

PGA

Top V iew

Summary of content (18 pages)

PAGE 1
Features • Fast Read Access Time – 150 ns • Automatic Page Write Operation • • • • • • • • • – Internal Address and Data Latches for 64 Bytes – Internal Control Timer Fast Write Cycle Times – Page Write Cycle Time: 3 ms or 10 ms Maximum – 1 to 64-byte Page Write Operation Low Power Dissipation – 50 mA Active Current – 200 µA CMOS Standby Current Hardware and Software Data Protection DATA Polling for End of Write Detection High Reliability CMOS Technology – Endurance: 104 or 105 Cycles – Data Retention: 10
PAGE 2
The AT28C256 is accessed like a Static RAM for the read or write cycle without the need for external components. The device contains a 64-byte page register to allow writing of up to 64 bytes simultaneously. During a write cycle, the addresses and 1 to 64 bytes of data are internally latched, freeing the address and data bus for other operations. Following the initiation of a write cycle, the device will automatically write the latched data using an internal control timer.
PAGE 3
AT28C256 Device Operation READ: The AT28C256 is accessed like a Static RAM. When CE and OE are low and WE is high, the data stored at the memory location determined by the address pins is asserted on the outputs. The outputs are put in the high impedance state when either CE or OE is high. This dualline control gives designers flexibility in preventing bus contention in their system. BYTE WRITE: A low pulse on the WE or CE input with CE or WE low (respectively) and OE high initiates a write cycle.
PAGE 4
DC and AC Operating Range AT28C256-15 AT28C256-20 AT28C256-25 0°C - 70°C 0°C - 70°C 0°C - 70°C Ind. -40°C - 85°C -40°C - 85°C -40°C - 85°C Mil. -55°C - 125°C -55°C - 125°C -55°C - 125°C -55°C - 125°C 5V ± 10% 5V ± 10% 5V ± 10% 5V ± 10% Mode CE OE WE I/O Read VIL VIL VIH DOUT VIL VIH VIL DIN VIH X(1) X High Z Write Inhibit X X VIH Write Inhibit X VIL X Output Disable X VIH X High Z Chip Erase VIL VH(3) VIL High Z Com.
PAGE 5
AT28C256 AC Read Characteristics Symbol Parameter tACC AT28C256-15 AT28C256-20 AT28C256-25 AT28C256-35 Min Min Min Min Max Max Max Max Units Address to Output Delay 150 200 250 350 ns (1) CE to Output Delay 150 200 250 350 ns (2) OE to Output Delay 0 70 0 80 0 100 0 100 ns tDF(3)(4) CE or OE to Output Float 0 50 0 55 0 60 0 70 ns tOH Output Hold from OE, CE or Address, whichever occurred first 0 tCE tOE 0 0 0 ns AC Read Waveforms(1)(2)(3)(4) Notes
PAGE 6
AC Write Characteristics Symbol Parameter tAS, tOES Address, OE Setup Time 0 ns tAH Address Hold Time 50 ns tCS Chip Select Setup Time 0 ns tCH Chip Select Hold Time 0 ns tWP Write Pulse Width (WE or CE) 100 ns tDS Data Setup Time 50 ns tDH, tOEH Data, OE Hold Time 0 ns tDV Note: Min Time to Data Valid 1.
PAGE 7
AT28C256 Page Mode Characteristics Symbol Parameter Min Max Units tWC Write Cycle Time (option available) AT28C256 10 ms AT28C256F 3 ms tAS Address Setup Time 0 ns tAH Address Hold Time 50 ns tDS Data Setup Time 50 ns tDH Data Hold Time 0 ns tWP Write Pulse Width 100 ns tBLC Byte Load Cycle Time tWPH Write Pulse Width High 150 50 µs ns Page Mode Write Waveforms(1)(2) Notes: 1.
PAGE 8
Software Data Protection Enable Algorithm(1) Software Data Protection Disable Algorithm(1) LOAD DATA AA TO ADDRESS 5555 LOAD DATA AA TO ADDRESS 5555 LOAD DATA 55 TO ADDRESS 2AAA LOAD DATA 55 TO ADDRESS 2AAA LOAD DATA A0 TO ADDRESS 5555 LOAD DATA 80 TO ADDRESS 5555 WRITES ENABLED(2) LOAD DATA XX TO ANY ADDRESS(4) LOAD DATA AA TO ADDRESS 5555 LOAD LAST BYTE TO LAST ADDRESS LOAD DATA 55 TO ADDRESS 2AAA ENTER DATA PROTECT STATE Notes for software program code: 1.
PAGE 9
AT28C256 Data Polling Characteristics(1) Symbol Parameter tDH Data Hold Time tOEH OE Hold Time Min Max OE to Output Delay tWR Write Recovery Time Units 0 ns 0 ns (2) tOE Notes: Typ ns 0 ns 1. These parameters are characterized and not 100% tested. 2. See “AC Read Characteristics”.
PAGE 10
AT28C256
PAGE 11
AT28C256 Ordering Information(2) ICC (mA) tACC (ns) Active Standby 150 50 0.2 200 Ordering Code Package AT28C256(E,F)-15JC AT28C256(E,F)-15PC AT28C256(E,F)-15SC AT28C256(E,F)-15TC 32J 28P6 28S 28T Operation Range Commercial (0°C to 70°C) AT28C256(E,F)-15JI AT28C256(E,F)-15PI AT28C256(E,F)-15SI AT28C256(E,F)-15TI 32J 28P6 28S 28T Industrial (-40°C to 85°C) 50 0.
PAGE 12
Ordering Information(2) ICC (mA) tACC (ns) Active Standby 250 50 0.2 150(3) Ordering Code Package AT28C256(E,F)-25JC AT28C256(E,F)-25PC AT28C256-W 32J 28P6 DIE Commercial (0°C to 70°C) AT28C256(E,F)-25JI AT28C256(E,F)-25PI 32J 28P6 Industrial (-40°C to 85°C) 50 0.3 AT28C256(E,F)-25DM/883 AT28C256(E,F)-25FM/883 AT28C256(E,F)-25LM/883 AT28C256(E,F)-25UM/883 AT28C256(E,F)-35UM/883 28D6 28F 32L 28U 28U Military/883C Class B, Fully Compliant (-55°C to 125°C) 50 0.
PAGE 13
AT28C256 Ordering Information(2) tACC (ns) 150 (3) 200(3) 250(3) ICC (mA) Active Standby 50 0.
PAGE 14
Ordering Information(2) ICC (mA) tACC (ns) Active Standby 250 50 0.35 300 350 Notes: Ordering Code Package Operation Range 5962-88525 05 UX 5962-88525 05 XX 5962-88525 05 YX 5962-88525 05 ZX 28U 28D6 32L 28F Military/883C Class B, Fully Compliant (-55°C to 125°C) 5962-88525 03 UX 5962-88525 03 XX 5962-88525 03 YX 5962-88525 03 ZX 28U 28D6 32L 28F Military/883C Class B, Fully Compliant (-55°C to 125°C) 50 0.
PAGE 15
AT28C256 Valid Part Numbers The following table lists standard Atmel products that can be ordered.
PAGE 16
Packaging Information 28D6, 28-lead, 0.600" Wide, Non-windowed Ceramic Dual Inline Package (Cerdip) Dimensions in Inches and (Millimeters) 28F, 28-lead, Non-windowed, Ceramic Bottombrazed Flat Package (Flatpack) Dimensions in Inches and (Millimeters) MIL-STD-1835 D-10 CONFIG A MIL-STD-1835 F-12 CONFIG B 1.49(37.9) 1.44(36.6) PIN 1 PIN #1 ID .370(9.40) .250(6.35) .019(.483) .015(.381) .610(15.5) .510(13.0) .050(1.27) BSC .728(18.5) .712(18.1) .098(2.49) MAX 1.300(33.02) REF .045(1.14) MAX .
PAGE 17
AT28C256 Packaging Information 28P6, 28-lead, 0.600" Wide, Plastic Dual Inline Package (PDIP) Dimensions in Inches and (Millimeters) 28S, 28-lead, 0.300" Wide, Plastic Gull Wing Small Outline (SOIC) Dimensions in Inches and (Millimeters) JEDEC STANDARD MS-011 AB 1.47(37.3) 1.44(36.6) PIN 1 .566(14.4) .530(13.5) .090(2.29) MAX 1.300(33.02) REF .220(5.59) MAX .005(.127) MIN SEATING PLANE .065(1.65) .015(.381) .022(.559) .014(.356) .161(4.09) .125(3.18) .110(2.79) .090(2.29) .012(.305) .008(.203) .
PAGE 18
Atmel Headquarters Atmel Operations Corporate Headquarters Atmel Colorado Springs 2325 Orchard Parkway San Jose, CA 95131 TEL (408) 441-0311 FAX (408) 487-2600 Europe 1150 E. Cheyenne Mtn. Blvd. Colorado Springs, CO 80906 TEL (719) 576-3300 FAX (719) 540-1759 Atmel Rousset Atmel U.K., Ltd.