ATMEL AT28HC256-12 256 32k x 8 high speed parallel eeprom Datasheet

AT28HC256
Features
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Fast Read Access Time - 70 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
80 mA Active Current
3 mA 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 Years
Single 5V ± 10% Supply
CMOS and TTL Compatible Inputs and Outputs
JEDEC Approved Byte-Wide Pinout
Full Military, Commercial, and Industrial Temperature Ranges
256 (32K x 8)
High Speed
CMOS
E2PROM
Description
The AT28HC256 is a high-performance Electrically Erasable and Programmable
Read Only Memory. Its 256K of memory is organized as 32,768 words by 8 bits.
Manufactured with Atmel’s advanced nonvolatile CMOS technology, the AT28HC256
offers access times to 70 ns with power dissipation of just 440 mW. When the
AT28HC256 is deselected, the standby current is less than 5 mA.
(continued)
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
PGA
Top View
TSOP
Top View
CERDIP, PDIP,
FLATPACK
Top View
AT28HC256
LCC, PLCC
Top View
Note: PLCC package pins 1 and
17 are DON’T CONNECT.
0007F
2-279
Description (Continued)
The AT28HC256 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 address and 1 to 64-bytes of data are internally latched, freeing the addresses 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 28HC256 has additional features to ensure high
quality and manufacturability. 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 E2PROM for device identification or tracking.
Block Diagram
Absolute Maximum Ratings*
Temperature Under Bias................. -55°C to +125°C
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
2-280
AT28HC256
*NOTICE: Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage 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.
AT28HC256
Device Operation
READ: The AT28HC256 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. 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 automatically 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.
PAGE WRITE: T h e p a g e w r i t e o p e r a t i o n o f t h e
AT28HC256 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 programming operation. All
bytes during a page write operation must reside on the
same page as defined by the state of the A6 - A14 inputs.
That is, 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.
DATA POLLING: The AT28HC256 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.
TOGGLE BIT: I n a d d i t i o n t o DATA P o l l i n g t h e
AT28HC256 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 toggling and valid data will be
read. Testing the toggle bit may begin at any time during
the write cycle.
DATA PROTECTION: If precautions are not taken, inadvertent writes to any 5-volt-only nonvolatile memory may
occur during transition of the host system power supply.
Atmel has incorporated both hardware and software features that will protect the memory against inadvertent
writes.
HARDWARE PROTECTION: Hardware features protect
against inadvertent writes to the AT28HC256 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; (d) noise filter - pulses of less than 15 ns (typical) on the WE or CE inputs will not initiate a write cycle.
SOFTWARE DATA PROTECTION: A software controlled
data protection feature has been implemented on the
AT28HC256. When enabled, the software data protection
(SDP), will prevent inadvertent writes. The SDP feature
may be enabled or disabled by the user; the AT28HC256
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 Algorithm). After writing the 3-byte command
sequence and after tWC the entire AT28HC256 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 AT28HC256. This is done by preceding the data to be written by the same 3-byte command
sequence.
Once set, SDP will remain active unless the disable command sequence is issued. Power transitions do not disable SDP and SDP will protect the AT28HC256 during
power-up and power-down conditions. All command sequences must conform to the page write timing specifications. It should also be noted that 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 three 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.
(continued)
2-281
Device Operation (Continued)
DEVICE IDENTIFICATION: A n e x t r a 6 4 - b y t e s o f
E2PROM memory are available to the user for device
identification. By raising 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.
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.
DC and AC Operating Range
Operating
Temperature (Case)
AT28HC256-70
AT28HC256-90
AT28HC256-12
0°C - 70°C
0°C - 70°C
0°C - 70°C
-40°C - 85°C
-40°C - 85°C
-40°C - 85°C
-55°C - 125°C
-55°C - 125°C
5V ± 10%
5V ± 10%
Com.
Ind.
Mil.
5V ± 10%
VCC Power Supply
Operating Modes
Mode
CE
OE
WE
I/O
Read
VIL
VIL
VIH
DOUT
Write (2)
VIL
VIH
VIL
DIN
VIH
(1)
Standby/Write Inhibit
X
X
High Z
Write Inhibit
X
X
VIH
Write Inhibit
X
VIL
X
Output Disable
X
VIH
X
High Z
VIL
High Z
Chip Erase
VIL
VH
Notes: 1. X can be VIL or VIH.
2. Refer to AC Programming Waveforms.
(3)
3. VH = 12.0V ± 0.5V.
DC Characteristics
Symbol
Parameter
Condition
Min
Max
Units
ILI
Input Load Current
VIN = 0V to VCC + 1V
10
µA
ILO
Output Leakage Current
VI/O = 0V to VCC
10
µA
ISB1
VCC Standby Current TTL
CE = 2.0V to VCC + 1V
AT28HC256-90, -12
3
mA
AT28HC256-70
60
mA
ISB2
VCC Standby Current CMOS
CE = -3.0V to VCC + 1V
AT28HC256-90, -12
300
µA
ICC
VCC Active Current
f = 5 MHz; IOUT = 0 mA
80
mA
VIL
Input Low Voltage
0.8
V
VIH
Input High Voltage
VOL
Output Low Voltage
IOL = 6.0 mA
VOH
Output High Voltage
IOH = -4 mA
2-282
2.0
AT28HC256
V
.45
2.4
V
V
AT28HC256
AC Read Characteristics
AT28HC256-70
Symbol
Parameter
tACC
Min
Max
AT28C256-90
Min
AT28HC256-12
Max
Min
Max
Units
Address to Output Delay
70
90
120
ns
tCE
(1)
CE to Output Delay
70
90
120
ns
tOE
(2)
OE to Output Delay
0
35
0
40
0
50
ns
tDF
(3, 4)
CE or OE to Output Float
0
35
0
40
0
50
ns
Output Hold from OE, CE or
Address, whichever occurred
first
0
tOH
0
0
ns
AC Read Waveforms (1, 2, 3, 4)
Notes: 1. CE may be delayed up to tACC - tCE after the address
transition without impact on tACC.
2. OE may be delayed up to tCE - tOE after the falling
edge of CE without impact on tCE or by tACC - tOE
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.
Output Test Load
Input Test Waveforms and
Measurement Level
tR, tF < 5 ns
Pin Capacitance (f = 1 MHz, T = 25°C) (1)
Typ
Max
Units
CIN
4
6
pF
VIN = 0V
COUT
8
12
pF
VOUT = 0V
Note:
Conditions
1. This parameter is characterized and is not 100% tested.
2-283
AC Write Characteristics
Symbol
Parameter
tAS, tOES
Address, OE Set-up Time
0
ns
tAH
Address Hold Time
50
ns
tCS
Chip Select Set-up Time
0
ns
tCH
Chip Select Hold Time
0
ns
tWP
Write Pulse Width (WE or CE)
100
ns
tDS
Data Set-up Time
50
ns
tDH, tOEH
Data, OE Hold Time
0
Time to Data Valid
tDV
Note:
1. NR = No Restriction
AC Write Waveforms
WE Controlled
CE Controlled
2-284
AT28HC256
Min
NR
Max
Units
ns
(1)
AT28HC256
Page Mode Write Characteristics
Symbol
Parameter
Min
Typ
Max
Units
tWC
Write Cycle Time
AT28HC256
5
10
ms
AT28HC256F
2
3.0
ms
tAS
Address Set-up Time
0
ns
tAH
Address Hold Time
50
ns
tDS
Data Set-up 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. 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.
Chip Erase Waveforms
tS = tH = 5 µsec (min.)
tW = 10 msec (min.)
VH = 12.0V ± 0.5V
2-285
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 AA
TO
ADDRESS 5555
LOAD DATA XX
TO
ANY ADDRESS (4)
LOAD LAST BYTE
TO
LAST ADDRESS
ENTER DATA
PROTECT STATE
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 55
TO
ADDRESS 2AAA
LOAD DATA 20
TO
ADDRESS 5555
EXIT DATA
PROTECT STATE (3)
LOAD DATA XX
TO
ANY ADDRESS (4)
LOAD LAST BYTE
TO
LAST ADDRESS
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.
2-286
AT28HC256
AT28HC256
Data Polling Characteristics (1)
Symbol
Parameter
tDH
Data Hold Time
tOEH
OE Hold Time
Min
Typ
Max
0
ns
0
ns
(2)
tOE
OE to Output Delay
tWR
Write Recovery Time
Units
ns
0
Notes: 1. These parameters are characterized and not 100% tested.
ns
2. See AC Read Characteristics.
Data Polling Waveforms
Toggle Bit Characteristics (1)
Symbol
Parameter
tDH
Data Hold Time
tOEH
OE Hold Time
Min
Typ
Max
10
ns
10
ns
(2)
tOE
OE to Output Delay
tOEHP
OE High Pulse
tWR
Write Recovery Time
Units
ns
150
ns
0
ns
Notes: 1. These parameters are characterized and not 100% tested.
2. See AC Read Characteristics.
Toggle Bit Waveforms
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.
2-287
2-288
AT28HC256
AT28HC256
Ordering Information (1)
tACC
ICC (mA)
Operation Range
AT28HC256(E,F)-70JC
AT28HC256(E,F)-70PC
32J
28P6
Commercial
(0°C to 70°C)
0.3
AT28HC256(E,F)-70JI
AT28HC256(E,F)-70PI
32J
28P6
Industrial
(-40°C to 85°C)
80
0.3
AT28HC256(E,F)-90JC
AT28HC256(E,F)-90PC
32J
28P6
Commercial
(0°C to 70°C)
80
0.3
AT28HC256(E,F)-90JI
AT28HC256(E,F)-90PI
32J
28P6
Industrial
(-40°C to 85°C)
80
0.3
AT28HC256(E,F)-90DM/883
AT28HC256(E,F)-90FM/883
AT28HC256(E,F)-90LM/883
AT28HC256(E,F)-90UM/883
28D6
28F
32L
28U
Military/883C
Class B, Fully Compliant
(-55°C to 125°C)
80
0.3
AT28HC256(E,F)-12JC
AT28HC256(E,F)-12PC
AT28HC256(E,F)-12SC
AT28HC256(E,F)-12TC
32J
28P6
28S
28T
Commercial
(0°C to 70°C)
80
0.3
AT28HC256(E,F)-12JI
AT28HC256(E,F)-12PI
AT28HC256(E,F)-12SI
AT28HC256(E,F)-12TI
32J
28P6
28S
28T
Industrial
(-40°C to 85°C)
80
0.3
AT28HC256(E,F)-12DM/883
AT28HC256(E,F)-12FM/883
AT28HC256(E,F)-12LM/883
AT28HC256(E,F)-12UM/883
28D6
28F
32L
28U
Military/883C
Class B, Fully Compliant
(-55°C to 125°C)
80
0.3
5962-88634 03 UX
5962-88634 03 XX
5962-88634 03 YX
5962-88634 03 ZX
28U
28D6
32L
28F
Military/883C
Class B, Fully Compliant
(-55°C to 125°C)
80
0.3
5962-88634 04 UX
5962-88634 04 XX
5962-88634 04 YX
5962-88634 04 ZX
28U
28D6
32L
28F
Military/883C
Class B, Fully Compliant
(-55°C to 125°C)
80
0.3
5962-88634 01 UX
5962-88634 01 XX
5962-88634 01 YX
5962-88634 01 ZX
28U
28D6
32L
28F
Military/883C
Class B, Fully Compliant
(-55°C to 125°C)
80
0.3
5962-88634 02 UX
5962-88634 02 XX
5962-88634 02 YX
5962-88634 02 ZX
28U
28D6
32L
28F
Military/883C
Class B, Fully Compliant
(-55°C to 125°C)
Active
Standby
70
80
60
80
90
120
90
120
Note:
Ordering Code
Package
(ns)
1. See Valid Part Number table below.
2-289
Ordering Information Note
Previous data sheets included the low power suffixes L, LE and LF on the AT28HC256 for 120 ns
and 90 ns speeds. The low power parameters are now standard; therefore, the L, LE and LF suffixes
are no longer required.
Valid Part Numbers
The following table lists standard Atmel products that can be ordered.
Device Numbers
Speed
Package and Temperature Combinations
AT28HC256
70
JC, JI, PC, PI
AT28HC256
90
JC, JI, PC, PI, TC, TI, DM/883, FM/883, UM/883
AT28HC256E
90
JC, JI, PC, PI, TC, TI, DM/883, FM/883, UM/883
AT28HC256F
90
JC, JI, PC, PI, TC, TI, DM/883, FM/883, UM/883
AT28HC256
12
JC, JI, PC, PI, TC, TI, DM/883, FM/883, UM/883
AT28HC256E
12
JC, JI, PC, PI, TC, TI, DM/883, FM/883, UM/883
AT28HC256F
12
JC, JI, PC, PI, TC, TI, DM/883, FM/883, UM/883
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)
32J
32 Lead, Plastic J-Leaded Chip Carrier (PLCC)
32L
32 Pad, Non-Windowed, Ceramic Leadless Chip Carrier (LCC)
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)
28U
28 Pin, Ceramic Pin Grid Array (PGA)
Options
Blank
Standard Device: Endurance = 10K Write Cycles; Write Time = 10 ms
E
High Endurance Option: Endurance = 100K Write Cycles
F
Fast Write Option: Write Time = 3 ms
2-290
AT28HC256
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