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: 104or 105Cycles
– Data Retention: 10 Years
•Single 5V ±10% Supply
•CMOS and TTL Compatible Inputs and Outputs
•JEDEC Approved Byte-wide Pinout
•Full Military and Industrial Temperature Ranges
•Green (Pb/Halide-free) Packaging Option
1. 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.
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. The end of a write cycle can be
detected by DATA Polling of I/O7. Once the end of a write cycle has been detected a
new access for a read or write can begin.
Atmel’s AT28C256 has additional features to ensure high quality and manufacturabil-
ity. The device utilizes internal error correction for extended endurance and improved
data retention characteristics. An optional software data protection mechanism is
available to guard against inadvertent writes. The device also includes an extra
64 bytes of EEPROM for device identification or tracking.
256K (32K x 8)
Paged Parallel
EEPROM
AT28C256
0006M–PEEPR–12/09
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0006M–PEEPR–12/09
AT28C256
2. Pin Configurations
Pin Name Function
A0 - A14 Addresses
CE Chip Enable
OE Output Enable
WE Write Enable
I/O0 - I/O7 Data Inputs/Outputs
NC No Connect
DC Don’t Connect
2.1 28-lead TSOP Top View
2.2 28-lead PGA Top View
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
OE
A11
A9
A8
A13
WE
VCC
A14
A12
A7
A6
A5
A4
A3
A10
CE
I/O7
I/O6
I/O5
I/O4
I/O3
GND
I/O2
I/O1
I/O0
A0
A1
A2
2.3 32-pad LCC, 28-lead PLCC Top View
Note: PLCC package pins 1 and 17 are Don’t Connect.
2.4 28-lead Cerdip/PDIP/Flatpack/SOIC –
Top View
5
6
7
8
9
10
11
12
13
29
28
27
26
25
24
23
22
21
A6
A5
A4
A3
A2
A1
A0
NC
I/O0
A8
A9
A11
NC
OE
A10
CE
I/O7
I/O6
4
3
2
1
32
31
30
14
15
16
17
18
19
20
I/O1
I/O2
GND
DC
I/O3
I/O4
I/O5
A7
A12
A14
DC
VCC
WE
A13
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
A14
A12
A7
A6
A5
A4
A3
A2
A1
A0
I/O0
I/O1
I/O2
GND
VCC
WE
A13
A8
A9
A11
OE
A10
CE
I/O7
I/O6
I/O5
I/O4
I/O3
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0006M–PEEPR–12/09
AT28C256
3. Block Diagram
4. Device Operation
4.1 Read
The AT28C256 is accessed like a Static RAM. When CEandOE 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 CEorOE is high. This dual-line
control gives designers flexibility in preventing bus contention in their system.
4.2 Byte Write
A low pulse on the WE or CE input with CE or WE low (respectively) and OE high initiates a write
cycle. The address is latched on the falling edge of CE or WE, whichever occurs last. The data is
latched by the first rising edge of CE or WE. Once a byte write has been started it will automati-
cally time itself to completion. Once a programming operation has been initiated and for the
duration of tWC, a read operation will effectively be a polling operation.
4.3 Page Write
The page write operation of the AT28C256 allows 1 to 64 bytes of data to be written into the
device during a single internal programming period. A page write operation is initiated in the
same manner as a byte write; the first byte written can then be followed by 1 to 63 additional
bytes. Each successive byte must be written within 150 µs (tBLC) of the previous byte. If the tBLC
limit is exceeded the AT28C256 will cease accepting data and commence the internal program-
ming operation. All bytes during a page write operation must reside on the same page as
defined by the state of the A6 - A14 inputs. For each WE high to low transition during the page
write operation, A6 - A14 must be the same.
The A0 to A5 inputs are used to specify which bytes within the page are to be written. The bytes
may be loaded in any order and may be altered within the same load period. Only bytes which
are specified for writing will be written; unnecessary cycling of other bytes within the page does
not occur.
4.4 DATA Polling
The AT28C256 features DATA Polling to indicate the end of a write cycle. During a byte or page
write cycle an attempted read of the last byte written will result in the complement of the written
data to be presented on I/O7. Once the write cycle has been completed, true data is valid on all
outputs, and the next write cycle may begin. DATA Polling may begin at anytime during the write
cycle.
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0006M–PEEPR–12/09
AT28C256
4.5 Toggle Bit
In addition to DATA Polling the AT28C256 provides another method for determining the end of a
write cycle. During the write operation, successive attempts to read data from the device will
result in I/O6 toggling between one and zero. Once the write has completed, I/O6 will stop tog-
gling and valid data will be read. Reading the toggle bit may begin at any time during the write
cycle.
4.6 Data Protection
If precautions are not taken, inadvertent writes may occur during transitions of the host system
power supply. Atmel has incorporated both hardware and software features that will protect the
memory against inadvertent writes.
4.6.1 Hardware Protection
Hardware features protect against inadvertent writes to the AT28C256 in the following ways: (a)
VCC sense – if VCC is below 3.8V (typical) the write function is inhibited; (b) VCC power-on delay –
once VCC has reached 3.8V the device will automatically time out 5 ms (typical) before allowing
a write; (c) write inhibit – holding any one of OE low, CE high or WE high inhibits write cycles;
and (d) noise filter – pulses of less than 15 ns (typical) on the WE or CE inputs will not initiate a
write cycle.
4.6.2 Software Data Protection
A software controlled data protection feature has been implemented on the AT28C256. When
enabled, the software data protection (SDP), will prevent inadvertent writes. The SDP feature
may be enabled or disabled by the user; the AT28C256 is shipped from Atmel with SDP
disabled.
SDP is enabled by the host system issuing a series of three write commands; three specific
bytes of data are written to three specific addresses (refer to “Software Data Protection” algo-
rithm). After writing the 3-byte command sequence and after tWC the entire AT28C256 will be
protected against inadvertent write operations. It should be noted, that once protected the host
may still perform a byte or page write to the AT28C256. This is done by preceding the data to be
written by the same 3-byte command sequence used to enable SDP.
Once set, SDP will remain active unless the disable command sequence is issued. Power transi-
tions do not disable SDP and SDP will protect the AT28C256 during power-up and power-down
conditions. All command sequences must conform to the page write timing specifications. The
data in the enable and disable command sequences is not written to the device and the memory
addresses used in the sequence may be written with data in either a byte or page write
operation.
After setting SDP, any attempt to write to the device without the 3-byte command sequence will
start the internal write timers. No data will be written to the device; however, for the duration of
tWC, read operations will effectively be polling operations.
4.7 Device Identification
An extra 64 bytes of EEPROM memory are available to the user for device identification. By rais-
ing A9 to 12V ±0.5V and using address locations 7FC0H to 7FFFH the additional bytes may be
written to or read from in the same manner as the regular memory array.
4.8 Optional Chip Erase Mode
The entire device can be erased using a 6-byte software code. Please see “Software Chip
Erase” application note for details.
5
0006M–PEEPR–12/09
AT28C256
Notes: 1. X can be VIL or VIH.
2. Refer to AC programming waveforms.
3. VH= 12.0V ± 0.5V.
5. DC and AC Operating Range
AT28C256-15 AT28C256-20 AT28C256-25 AT28C256-35
Operating Temperature
(Case)
Ind. -40°C - 85°C
Mil. -55°C - 125°C -55°C - 125°C -55°C - 125°C -55°C - 125°C
VCC Power Supply 5V ± 10% 5V ± 10% 5V ± 10% 5V ± 10%
6. Operating Modes
Mode CE OE WE I/O
Read VIL VIL VIH DOUT
Write(2) VIL VIH VIL DIN
Standby/Write Inhibit 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
7. Absolute Maximum Ratings*
Temperature under Bias ................................ -55°C to +125°C *NOTICE: Stresses beyond those listed under “Absolute
Maximum Ratings” may cause permanent dam-
age to the device. This is a stress rating only and
functional operation of the device at these or any
other conditions beyond those indicated in the
operational sections of this specification is not
implied. Exposure to absolute maximum rating
conditions for extended periods may affect
device reliability
Storage Temperature..................................... -65°C to +150°C
All Input Voltages
(including NC Pins)
with Respect to Ground ...................................-0.6V to +6.25V
All Output Voltages
with Respect to Ground .............................-0.6V to VCC + 0.6V
Voltage on OE and A9
with Respect to Ground ...................................-0.6V to +13.5V
8. DC Characteristics
Symbol Parameter Condition Min Max Units
ILI Input Load Current VIN =0VtoV
CC +1V 10 µA
ILO Output Leakage Current VI/O =0VtoV
CC 10 µA
ISB1 VCC Standby Current CMOS CE = VCC - 0.3V to VCC +1V Ind. 200 µA
Mil. 300 µA
ISB2 VCC Standby Current TTL CE = 2.0V to VCC +1V 3 mA
ICC VCC Active Current f = 5 MHz; IOUT =0mA 50 mA
VIL Input Low Voltage 0.8 V
VIH Input High Voltage 2.0 V
VOL Output Low Voltage IOL = 2.1 mA 0.45 V
VOH Output High Voltage IOH = -400 µA 2.4 V
6
0006M–PEEPR–12/09
AT28C256
10. AC Read Waveforms(1)(2)(3)(4)
Notes: 1. CE may be delayed up to tACC -t
CE after the address transition without impact on tACC.
2. OE may be delayed up to tCE -t
OE after the falling edge of CE without impact on tCE or by tACC -t
OE after an address change
without impact on tACC.
3. tDF is specified from OE or CE whichever occurs first (CL= 5 pF).
4. This parameter is characterized and is not 100% tested.
9. AC Read Characteristics
Symbol Parameter
AT28C256-15 AT28C256-20 AT28C256-25 AT28C256-35
UnitsMin Max Min Max Min Max Min Max
tACC Address to Output Delay 150 200 250 350 ns
tCE(1) CE to Output Delay 150 200 250 350 ns
tOE(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 0000 ns
8
0006M–PEEPR–12/09
AT28C256
Note: 1. NR = No Restriction
15. AC Write Waveforms
15.1 WE Controlled
15.2 CE Controlled
14. AC Write Characteristics
Symbol Parameter Min Max Units
tAS,t
OES 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,t
OEH Data, OE Hold Time 0 ns
tDV Time to Data Valid NR(1)
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0006M–PEEPR–12/09
AT28C256
17. Page Mode Write Waveforms(1)(2)
Notes: 1. A6 through A14 must specify the same page address during each high to low transition of WE (or CE).
2. OE must be high only when WE and CE are both low.
18. Chip Erase Waveforms
16. 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 150 µs
tWPH Write Pulse Width High 50 ns
tS=t
H= 5 µsec (min.)
tW= 10 msec (min.)
VH= 12.0V ± 0.5V
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0006M–PEEPR–12/09
AT28C256
19. Software Data Protection
Enable Algorithm(1)
Notes: 1. Data Format: I/O7 - I/O0 (Hex);
Address Format: A14 - A0 (Hex).
2. Write Protect state will be activated at end of write
even if no other data is loaded.
3. Write Protect state will be deactivated at end of write
period even if no other data is loaded.
4. 1 to 64 bytes of data are loaded.
LOAD DATA AA
TO
ADDRESS 5555
LOAD DATA 55
TO
ADDRESS 2AAA
LOAD DATA A0
TO
ADDRESS 5555
LOAD DATA XX
TO
ANY ADDRESS
(4)
LOAD LAST BYTE
TO
LAST ADDRESS ENTER DATA
PROTECT STATE
WRITES ENABLED
(2)
20. Software Data Protection
Disable Algorithm(1)
LOAD DATA AA
TO
ADDRESS 5555
LOAD DATA 55
TO
ADDRESS 2AAA
LOAD DATA 80
TO
ADDRESS 5555
LOAD DATA AA
TO
ADDRESS 5555
LOAD DATA 20
TO
ADDRESS 5555
LOAD DATA XX
TO
ANY ADDRESS
(4)
LOAD LAST BYTE
TO
LAST ADDRESS
LOAD DATA 55
TO
ADDRESS 2AAA
EXIT DATA
PROTECT STATE
(3)
21. Software Protected Write Cycle Waveforms(1)(2)
Notes: 1. A6 through A14 must specify the same page address during each high to low transition of WE (or CE) after the software
code has been entered.
2. OE must be high only when WE and CE are both low.
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0006M–PEEPR–12/09
AT28C256
Notes: 1. These parameters are characterized and not 100% tested.
2. See“AC Read Characteristics” on page 6.
23. Data Polling Waveforms
Notes: 1. These parameters are characterized and not 100% tested.
2. See “AC Read Characteristics” on page 6.
25. Toggle Bit Waveforms(1)(2)(3)
Notes: 1. Toggling either OE or CE or both OE and CE will operate toggle bit.
2. Beginning and ending state of I/O6 will vary.
3. Any address location may be used but the address should not vary.
22. Data Polling Characteristics(1)
Symbol Parameter Min Typ Max Units
tDH Data Hold Time 0 ns
tOEH OE Hold Time 0 ns
tOE OE to Output Delay(2) ns
tWR Write Recovery Time 0 ns
24. Toggle Bit Characteristics(1)
Symbol Parameter Min Typ Max Units
tDH Data Hold Time 10 ns
tOEH OE Hold Time 10 ns
tOE OE to Output Delay(2) ns
tOEHP OE High Pulse 150 ns
tWR Write Recovery Time 0 ns
12
0006M–PEEPR–12/09
AT28C256
26. Normalized ICC Graphs
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0006M–PEEPR–12/09
AT28C256
27. Ordering Information
27.1 27.1Military Dual Marked Package
27.1.1 AT28C256
Note: 1. Where two DESC numbers apply to the Atmel ordering code apply SL815 to receive parts with the noted DESC number dual
marked along with Atmel part number.
tACC ICC (mA)
(ns) Active Standby Ordering Code Package Operation Range
150 50 0.3 AT28C256-15DM/883
5962-88525 14 XX(1)
5962-88525 06 XX
28D6
Military/883C
Class B, Fully Compliant
(-55°C to 125°C)
AT28C256-15FM/883
5962-88525 14 ZX(1)
5962-88525 06 ZX
28F
AT28C256-15LM/883
5962-88525 14 YX(1)
5962-88525 06 YX
32L
AT28C256-15UM/883
5962-88525 14 UX(1)
5962-88525 06 UX
28U
200 50 0.3 AT28C256-20DM/883
5962-88525 12 XX(1)
5962-88525 04 XX
28D6
Military/883C
Class B, Fully Compliant
(-55°C to 125°C)
AT28C256-20FM/883
5962-88525 12 ZX(1)
5962-88525 04 ZX
28F
AT28C256-20LM/883
5962-88525 12 YX(1)
5962-88525 04 YX
32L
AT28C256-20UM/883
5962-88525 12 UX(1)
5962-88525 04 UX
28U
250 50 0.3 AT28C256-25DM/883
5962-88525 11 XX(1)
5962-88525 03 XX
28D6
Military/883C
Class B, Fully Compliant
(-55°C to 125°C)
AT28C256-25FM/883
5962-88525 11 ZX(1)
5962-88525 03 ZX
28F
AT28C256-25LM/883
5962-88525 11 YX(1)
5962-88525 03 YX
32L
AT28C256-25UM/883
5962-88525 11 UX(1)
5962-88525 03 UX
28U
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0006M–PEEPR–12/09
AT28C256
27.1.2 AT28C256E
Note: 1. Where two DESC numbers apply to the Atmel ordering code apply SL815 to receive parts with the noted DESC number dual
marked along with Atmel part number.
tACC ICC (mA)
(ns) Active Standby Ordering Code Package Operation Range
150 50 0.3 AT28C256E-15DM/883
5962-88525 16 XX(1)
5962-88525 08 XX
28D6
Military/883C
Class B, Fully Compliant
(-55°C to 125°C)
AT28C256E-15FM/883
5962-88525 16 ZX(1)
5962-88525 08 ZX
28F
AT28C256E-15LM/883
5962-88525 16 YX(1)
5962-88525 08 YX
32L
AT28C256E-15UM/883
5962-88525 16 UX(1)
5962-88525 08 UX
28U
200 50 0.3 AT28C256E-20DM/883 28D6
Military/883C
Class B, Fully Compliant
(-55°C to 125°C)
AT28C256E-20FM/883 28F
AT28C256E-20LM/883 32L
AT28C256E-20UM/883 28U
250 50 0.3 AT28C256E-25DM/883
5962-88525 13 XX(1)
5962-88525 05 XX
28D6
Military/883C
Class B, Fully Compliant
(-55°C to 125°C)
5962-88525 05 XX
5962-88525 13 ZX(1)
5962-88525 05 ZX
28F
AT28C256E-25LM/883
5962-88525 13 YX(1)
5962-88525 05 YX
32L
AT28C256E-25UM/883
5962-88525 13 UX(1)
5962-88525 05 UX
28U
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0006M–PEEPR–12/09
AT28C256
27.1.3 AT28C256F
Notes: 1. Electrical specifications for these speeds are defined by Standard Microcircuit Drawing 5962-88525.
2. SMD specifies Software Data Protection feature for device type, although Atmel product supplied to every device type in the
SMD is 100% tested for this feature.
3. Where two DESC numbers apply to the Atmel ordering code apply SL815 to receive parts with the noted DESC number dual
marked along with Atmel part number.
tACC ICC (mA)
(ns) Active Standby Ordering Code Package Operation Range
150 50 0.3 AT28C256F-15DM/883
5962-88525 15 XX(3)
5962-88525 07 XX
28D6
Military/883C
Class B, Fully Compliant
(-55°C to 125°C)
AT28C256F-15FM/883
5962-88525 15 ZX(3)
5962-88525 07 ZX
28F
AT28C256F-15LM/883
5962-88525 15 YX(3)
5962-88525 07 YX
32L
AT28C256F-15UM/883
5962-88525 15 UX(3)
5962-88525 07 UX
28U
Package Type
28D6 28-lead, 0.600" Wide, Non-windowed, Ceramic Dual Inline Package (Cerdip)
28F 28-lead, Non-windowed, Ceramic Bottom-brazed Flat Package (Flatpack)
32L 32-pad, Non-windowed, Ceramic Leadless Chip Carrier (LCC)
28U 28-pin, Ceramic Pin Grid Array (PGA)
WDie
Options
Blank Standard Device: Endurance = 10K Write Cycles; Write Time = 10 ms
EHigh Endurance Option: Endurance = 100K Write Cycles
FFast Write Option: Write Time=3ms
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0006M–PEEPR–12/09
AT28C256
27.2 Industrial Green Package Option (Pb/Halide-free)
27.2.1 AT28C256
27.2.2 AT28C256E
27.2.3 AT28C256F
28. Die Products
tACC ICC (mA)
(ns) Active Standby Ordering Code Package Operation Range
150 50 0.2 AT28C256-15JU
AT28C256-15PU
AT28C256-15SU
AT28C256-15TU
32J
28P6
28S
28T
Industrial
(-40°C to 85°C)
tACC ICC (mA)
(ns) Active Standby Ordering Code Package Operation Range
150 50 0.2 AT28C256E-15JU
AT28C256E-15SU
AT28C256E-15TU
32J
28S
28T
Industrial
(-40°C to 85°C)
tACC ICC (mA)
(ns) Active Standby Ordering Code Package Operation Range
150 50 0.2 AT28C256F-15JU
AT28C256F-15SU
AT28C256F-15TU
32J
28S
28T
Industrial
(-40°C to 85°C)
Package Type
32J 32-lead, Plastic J-leaded Chip Carrier (PLCC)
28P6 28-lead, 0.600" Wide, Plastic Dual Inline Package (PDIP)
28S 28-lead, 0.300" Wide, Plastic Gull Wing Small Outline (SOIC)
28T 28-lead, Plastic Thin Small Outline Package (TSOP)
Options
Blank Standard Device: Endurance = 10K Write Cycles; Write Time = 10 ms
EHigh Endurance Option: Endurance = 100K Write Cycles
FFast Write Option: Write Time=3ms
Reference Section: Contact Atmel sales for die sales options.
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0006M–PEEPR–12/09
AT28C256
29. Packaging Information
29.1 28D6 – Cerdip
2325 Orchard Parkway
San Jose, CA 95131
TITLE DRAWING NO.
R
REV.
28D6, 28-lead, 0.600" Wide, Non-windowed,
Ceramic Dual Inline Package (Cerdip) B
28D6
10/23/03
37.85(1.490)
36.58(1.440)
PIN
1
15.49(0.610)
12.95(0.510)
0.127(0.005)MIN
1.52(0.060)
0.38(0.015)
0.66(0.026)
0.36(0.014)
1.65(0.065)
1.14(0.045)
15.70(0.620)
15.00(0.590)
17.80(0.700) MAX
0.46(0.018)
0.20(0.008)
2.54(0.100)BSC
5.08(0.200)
3.18(0.125)
SEATING
PLANE
5.72(0.225)
MAX
33.02(1.300) REF
0º~ 15º REF
Dimensions in Millimeters and (Inches).
Controlling dimension: Inches.
MIL-STD 1835 D-10 Config A (Glass Sealed)
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0006M–PEEPR–12/09
AT28C256
29.2 28F – Flatpack
2325 Orchard Parkway
San Jose, CA 95131
TITLE DRAWING NO.
R
REV.
28F, 28-lead, Non-windowed, Ceramic Bottom-brazed
Flat Package (FlatPack) B
28F
10/21/03
Dimensions in Millimeters and (Inches).
Controlling dimension: Inches.
MIL-STD 1835 F-12 Config B
PIN #1 ID 9.40(0.370)
6.35(0.250)
0.56(0.022)
0.38(0.015)
1.27(0.050) BSC
1.14(0.045) MAX
3.02(0.119)
2.29(0.090)
1.14(0.045)
0.660(0.026)
7.26(0.286)
6.96(0.274)
1.96(0.077)
1.09(0.043)
0.23(0.009)
0.10(0.004)
10.57(0.416)
9.75(0.384)
18.49(0.728)
18.08(0.712)
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0006M–PEEPR–12/09
AT28C256
29.3 32J – PLCC
DRAWING NO. REV.
2325 Orchard Parkway
San Jose, CA 95131
R
TITLE
32J, 32-lead, Plastic J-leaded Chip Carrier (PLCC) B
32J
10/04/01
1.14(0.045) X 45 PIN NO. 1
IDENTIFIER
1.14(0.045) X 45
0.51(0.020)MAX
0.318(0.0125)
0.191(0.0075)
A2
45 MAX (3X)
A
A1
B1 E2
B
e
E1 E
D1
D
D2
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL MIN NOM MAX NOTE
Notes: 1. This package conforms to JEDEC reference MS-016, Variation AE.
2. Dimensions D1 and E1 do not include mold protrusion.
Allowable protrusion is .010"(0.254 mm) per side. Dimension D1
and E1 include mold mismatch and are measured at the extreme
material condition at the upper or lower parting line.
3. Lead coplanarity is 0.004" (0.102 mm) maximum.
A 3.175 – 3.556
A1 1.524 – 2.413
A2 0.381 – –
D 12.319 – 12.573
D1 11.354 – 11.506 Note 2
D2 9.906 – 10.922
E 14.859 – 15.113
E1 13.894 – 14.046 Note 2
E2 12.471 – 13.487
B 0.660 – 0.813
B1 0.330 – 0.533
e 1.270 TYP
20
0006M–PEEPR–12/09
AT28C256
29.4 32L – LCC
2325 Orchard Parkway
San Jose, CA 95131
TITLE DRAWING NO.
R
REV.
32L, 32-pad, Non-windowed, Ceramic Lid, Leadless Chip
Carrier (LCC) B
32L
10/21/03
Dimensions in Millimeters and (Inches).
Controlling dimension: Inches.
MIL-STD 1835 C-12
11.63(0.458)
11.23(0.442)
14.22(0.560)
13.72(0.540)
2.54(0.100)
2.16(0.085)
1.91(0.075)
1.40(0.055)
INDEX CORNER
0.635(0.025)
0.381(0.015) X 45˚
0.305(0.012)
0.178(0.007)RADIUS
0.737(0.029)
0.533(0.021)
1.02(0.040) X 45˚
PIN 1
1.40(0.055)
1.14(0.045)
2.41(0.095)
1.91(0.075)
2.16(0.085)
1.65(0.065)
7.62(0.300) BSC
1.27(0.050) TYP
10.16(0.400) BSC
21
0006M–PEEPR–12/09
AT28C256
29.5 28P6 – PDIP
2325 Orchard Parkway
San Jose, CA 95131
TITLE DRAWING NO.
R
REV.
28P6, 28-lead (0.600"/15.24 mm Wide) Plastic Dual
Inline Package (PDIP) B
28P6
09/28/01
PIN
1
E1
A1
B
REF
E
B1
C
L
SEATING PLANE
A
0º ~ 15º
D
e
eB
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL MIN NOM MAX NOTE
A – – 4.826
A1 0.381 – –
D 36.703 – 37.338 Note 2
E 15.240 – 15.875
E1 13.462 – 13.970 Note 2
B 0.356 – 0.559
B1 1.041 – 1.651
L 3.048 – 3.556
C 0.203 – 0.381
eB 15.494 – 17.526
e 2.540 TYP
Notes: 1. This package conforms to JEDEC reference MS-011, Variation AB.
2. Dimensions D and E1 do not include mold Flash or Protrusion.
Mold Flash or Protrusion shall not exceed 0.25 mm (0.010").
22
0006M–PEEPR–12/09
AT28C256
29.6 28S – SOIC
2325 Orchard Parkway
San Jose, CA 95131
TITLE DRAWING NO.
R
REV.
28S, 28-lead, 0.300" Body, Plastic Gull Wing Small Outline (SOIC)
JEDEC Standard MS-013 B
28S
8/4/03
Dimensions in Millimeters and (Inches).
Controlling dimension: Millimeters.
TOP VIEW
SIDE VIEWS
0.51(0.020)
0.33(0.013)
7.60(0.2992)
7.40(0.2914)
10.65(0.419)
10.00(0.394)
1.27(0.50) BSC
2.65(0.1043)
2.35(0.0926)
18.10(0.7125)
17.70(0.6969)
0.30(0.0118)
0.10(0.0040)
0.32(0.0125)
0.23(0.0091)
1.27(0.050)
0.40(0.016)
0º ~ 8º
PIN 1
23
0006M–PEEPR–12/09
AT28C256
29.7 28T – TSOP
2325 Orchard Parkway
San Jose, CA 95131
TITLE DRAWING NO.
R
REV.
28T, 28-lead (8 x 13.4 mm) Plastic Thin Small Outline
Package, Type I (TSOP) C
28T
12/06/02
PIN 1 0º ~ 5º
D1 D
Pin 1 Identifier Area
b
e
EA
A1
A2
c
L
GAGE PLANE
SEATING PLANE
L1
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL MIN NOM MAX NOTE
Notes: 1. This package conforms to JEDEC reference MO-183.
2. Dimensions D1 and E do not include mold protrusion. Allowable
protrusion on E is 0.15 mm per side and on D1 is 0.25 mm per side.
3. Lead coplanarity is 0.10 mm maximum.
A – – 1.20
A1 0.05 – 0.15
A2 0.90 1.00 1.05
D 13.20 13.40 13.60
D1 11.70 11.80 11.90 Note 2
E 7.90 8.00 8.10 Note 2
L 0.50 0.60 0.70
L1 0.25 BASIC
b 0.17 0.22 0.27
c 0.10 – 0.21
e 0.55 BASIC
24
0006M–PEEPR–12/09
AT28C256
29.8 28U – PGA
2325 Orchard Parkway
San Jose, CA 95131
TITLE DRAWING NO.
R
REV.
28U, 28-pin, Ceramic Pin Grid Array (PGA) B
28U
10/21/03
Dimensions in Millimeters and (Inches).
Controlling dimension: Inches.
13.74(0.540)
13.36(0.526)
15.24(0.600)
14.88(0.586)
2.57(0.101)
2.06(0.081)
7.26(0.286)
6.50(0.256)
1.40(0.055)
1.14(0.045)
0.58(0.023)
0.43(0.017)
3.12(0.123)
2.62(0.103)
1.83(0.072)
1.57(0.062)
14.17(0.558)
13.77(0.542)
12.70(0.500) TYP
2.54(0.100) TYP
16.71(0.658)
16.31(0.642)
2.54(0.100) TYP
10.41(0.410)
9.91(0.390)
0006M–PEEPR–12/09
Headquarters International
Atmel Corporation
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Tel: 1(408) 441-0311
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