28C64A
64K (8K x 8) CMOS EEPROM
FEATURES
PACKAGE TYPES
• Fast Read Access Time—150 ns
• CMOS Technology for Low Power Dissipation
- 30 mA Active
RDY/BSY
A12
A7
• 1
2
28 Vcc
27 WE
26 NC
25 A8
3
A6
4
A6
A5
A4
A3
A2
A1 10
A0 11
NC 12
I/O0 13
5
6
7
8
9
29 A8
28 A9
A5
5
24 A9
- 100 µA Standby
A4
6
23 A11
22 OE
21 A10
20 CE
19 I/O7
18 I/O6
17 I/O5
16 I/O4
15 I/O3
27 A11
26 NC
25 OE
24 A10
23 CE
22 I/O7
21 I/O6
• Fast Byte Write Time—200 µs or 1 ms
• Data Retention >200 years
• High Endurance - Minimum 100,000 Erase/Write
Cycles
• Automatic Write Operation
- Internal Control Timer
A3
7
A2
8
A1
9
A0
10
11
12
13
I/O0
I/O1
I/O2
VSS 14
- Auto-Clear Before Write Operation
- On-Chip Address and Data Latches
• Data Polling
• Ready/Busy
• Chip Clear Operation
• Pin 1 indicator on PLCC on top of package
OE
A11
A9
1
2
3
4
5
6
7
28
A10
27 CE
26 I/07
25 I/06
24 I/05
23 I/04
22 I/03
A8
NC
WE
Vcc
• Enhanced Data Protection
- VCC Detector
- Pulse Filter
- Write Inhibit
21
RDY/BSY
A12
8
9
Vss
20 I/02
19 I/01
18 I/00
17 A0
16 A1
15 A2
A7 10
A6 11
A5 12
A4 13
A3 14
• Electronic Signature for Device Identification
• 5-Volt-Only Operation
• Organized 8Kx8 JEDEC Standard Pinout
- 28-pin Dual-In-Line Package
- 32-pin PLCC Package
- 28-pin Thin Small Outline Package (TSOP)
8x20mm
- 28-pin Very Small Outline Package (VSOP)
8x13.4mm
OE
A11
A9
A8
NC
WE
22
23
24
25
26
27
A10
CE
21
20
19
18
17
16
15
14
13
12
11
10
9
I/O7
I/O6
I/O5
I/O4
I/O3
28
1
VCC
RDY/BSY
A12
A7
V
SS
2
3
4
5
6
7
I/O2
I/O1
I/O0
A0
A1
A2
• Available for Extended Temperature Ranges:
- Commercial: 0˚C to +70˚C
A6
A5
A4
A3
8
DESCRIPTION
BLOCK DIAGRAM
The Microchip Technology Inc. 28C64A is a CMOS 64K non-
volatile electrically Erasable PROM. The 28C64A is
accessed like a static RAM for the read or write cycles without
the need of external components. During a “byte write”, the
address and data are latched internally, freeing the micropro-
cessor address and data bus for other operations. Following
the initiation of write cycle, the device will go to a busy state
and automatically clear and write the latched data using an
internal control timer. To determine when the write cycle is
complete, the user has a choice of monitoring the Ready/
Busy output or using Data polling. The Ready/Busy pin is an
open drain output, which allows easy configuration in wired-
or systems. Alternatively, Data polling allows the user to read
the location last written to when the write operation is com-
plete. CMOS design and processing enables this part to be
used in systems where reduced power consumption and reli-
ability are required. A complete family of packages is offered
to provide the utmost flexibility in applications
I/O0
I/O7
VSS
Data Protection
VCC
Circuitry
Chip Enable/
Output Enable
Control Logic
CE
OE
WE
Input/Output
Buffers
Auto Erase/Write
Timing
Data
Poll
Rdy/
Busy
Program Voltage
Generation
A0
Y
Y Gating
Decoder
L
a
t
c
h
e
s
16K bit
Cell Matrix
X
Decoder
A12
1996 Microchip Technology Inc.
DS11109H-page 1
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