AT28HC256
Military Grade 256-Kbit (32,768 x 8) High-Speed
Paged Parallel EEPROM
Features
•
•
Fast Read Access Time: 90 ns
Automatic Page Write Operation:
– Internally organized as 32,768 x 8 (256K)
– Internal address and data latches for 64 bytes
– Internal control timer
Fast Write Cycle Time:
– 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 CMOS standby current
Hardware and Software Data Protection
DATA Polling for End of Write Detection
High Reliability CMOS Technology:
– Endurance: 10,000 or 100,000 cycles
– Data retention: 10 years
Single 5V ± 10% Supply
CMOS and TTL Compatible Inputs and Outputs
®
JEDEC Approved Byte-Wide Pinout
Full Military Temperature Range
•
•
•
•
•
•
•
•
•
Packages
•
32-Lead CERDIP, 32-Lead Flatpack, 32-Lead CLCC and 30-Pin PGA
©
2020 Microchip Technology Inc.
Datasheet
DS20006352A-page 1
AT28HC256
Table of Contents
Features......................................................................................................................................................... 1
Packages........................................................................................................................................................1
1.
2.
3.
Package Types (not to scale)..................................................................................................................4
Pin Descriptions...................................................................................................................................... 5
Description.............................................................................................................................................. 6
3.1.
4.
Block Diagram.............................................................................................................................. 6
Electrical Characteristics.........................................................................................................................7
4.1.
4.2.
4.3.
4.4.
Absolute Maximum Ratings..........................................................................................................7
DC and AC Operating Range.......................................................................................................7
DC Characteristics....................................................................................................................... 7
Pin Capacitance........................................................................................................................... 8
5.
6.
Normalized I
CC
Graphics.........................................................................................................................9
Device Operation.................................................................................................................................. 10
6.1.
6.2.
6.3.
6.4.
6.5.
6.6.
6.7.
6.8.
6.9.
6.10.
6.11.
6.12.
6.13.
6.14.
6.15.
6.16.
6.17.
Operating Modes........................................................................................................................ 11
AC Read Characteristics............................................................................................................ 11
AC Read Waveforms..................................................................................................................12
Input Test Waveforms and Measurement Level......................................................................... 12
Output Test Load........................................................................................................................ 12
AC Write Characteristics............................................................................................................ 13
AC Write Waveforms.................................................................................................................. 13
Page Mode Characteristics........................................................................................................ 14
Page Mode Write Waveforms
(1,2)
............................................................................................... 15
Chip Erase Waveforms...............................................................................................................15
Software Data Protection Enable Algorithm
(1)
............................................................................16
Software Data Protection Disable Algorithm
(1)
...........................................................................17
Software Protected Program Cycle Waveform
(1,2)
..................................................................... 18
Data Polling Characteristics
(1)
....................................................................................................18
Data Polling Waveforms............................................................................................................. 19
Toggle Bit Characteristics
(1)
....................................................................................................... 19
Toggle Bit Waveforms.................................................................................................................19
7.
Packaging Information.......................................................................................................................... 21
7.1.
Package Marking Information.....................................................................................................21
8.
Revision History.................................................................................................................................... 26
The Microchip Website.................................................................................................................................27
Product Change Notification Service............................................................................................................27
Customer Support........................................................................................................................................ 27
Product Identification System.......................................................................................................................28
©
2020 Microchip Technology Inc.
Datasheet
DS20006352A-page 2
AT28HC256
Microchip Devices Code Protection Feature................................................................................................ 29
Legal Notice................................................................................................................................................. 30
Trademarks.................................................................................................................................................. 30
Quality Management System....................................................................................................................... 31
Worldwide Sales and Service.......................................................................................................................32
©
2020 Microchip Technology Inc.
Datasheet
DS20006352A-page 3
AT28HC256
Package Types (not to scale)
1.
Package Types (not to scale)
32-Pad CLCC
(1)
Top View
A7
A12
A14
DC
V
CC
WE
A13
28-Lead PGA
Top View
I/O1
I/O2
GND
DC
I/O3
I/O4
I/O5
14
15
16
17
18
19
20
A6
A5
A4
A3
A2
A1
A0
NC
I/O0
5
6
7
8
9
10
11
12
13
4
3
2
1
32
31
30
29
28
27
26
25
24
23
22
21
A8
A9
A11
NC
OE
A10
CE
I/O7
I/O6
28-Lead
Cerdip/Flatpack
Top View
A14
A12
A7
A6
A5
A4
A3
A2
A1
A0
I/O0
I/O1
I/O2
GND
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
V
CC
WE
A13
A8
A9
A11
OE
A10
CE
I/O7
I/O6
I/O5
I/O4
I/O3
Note:
1. CLCC package pins 1 and 17 are “Don’t Connect”.
©
2020 Microchip Technology Inc.
Datasheet
DS20006352A-page 4
AT28HC256
Pin Descriptions
2.
Pin Descriptions
The descriptions of the pins are listed in
Table 2-1.
Table 2-1. Pin Function Table
Name
DC
A14
A12
A7
A6
A5
A4
A3
A2
A1
A0
NC
I/O0
I/O1
I/O2
GND
DC
I/O3
I/O4
I/O5
I/O6
I/O7
CE
A10
OE
NC
A11
A9
A8
A13
WE
V
CC
32‑Lead CERDIP
—
1
2
3
4
5
6
7
8
9
10
—
11
12
13
14
—
15
16
17
18
19
20
21
22
—
23
24
25
26
27
28
32-Lead CLCC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
32-Lead
FLATPACK
—
1
2
3
4
5
6
7
8
9
10
—
11
12
13
14
—
15
16
17
18
19
20
21
22
—
23
24
25
26
27
28
30‑Pin PGA
—
1
2
3
4
5
6
7
8
9
10
—
11
12
13
14
—
15
16
17
18
19
20
21
22
—
23
24
25
26
27
28
Function
Don’t Connect
Address
Address
Address
Address
Address
Address
Address
Address
Address
Address
No Connect
Data Input/Output
Data Input/Output
Data Input/Output
Ground
Don’t Connect
Data Input/Output
Data Input/Output
Data Input/Output
Data Input/Output
Data Input/Output
Chip Enable
Address
Output Enable
No Connect
Address
Address
Address
Address
Write Enable
Device Power
Supply
©
2020 Microchip Technology Inc.
Datasheet
DS20006352A-page 5
