Obsolete Device
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
- 100 µA Standby
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
• 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
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
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
• Pin 1 indicator on PLCC on top of package
• Ready/Busy
• Chip Clear Operation
• Enhanced Data Protection
- VCC Detector
BLOCK DIAGRAM
I/O0
I/O7
- Pulse Filter
- Write Inhibit
VSS
Data Protection
VCC
Circuitry
Chip Enable/
Output Enable
Control Logic
CE
• Electronic Signature for Device Identification
• 5-Volt-Only Operation
• Organized 8Kx8 JEDEC Standard Pinout
- 28-pin Dual-In-Line Package
- 32-pin PLCC Package
OE
WE
Input/Output
Buffers
Auto Erase/Write
Timing
Data
Poll
Rdy/
Busy
Program Voltage
Generation
A0
- 28-pin SOIC Package
Y
Y Gating
Decoder
L
• Available for Extended Temperature Ranges:
- Commercial: 0°C to +70°C
a
t
c
h
e
s
16K bit
Cell Matrix
- Industrial:
-40°C to +85°C
X
Decoder
DESCRIPTION
A12
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 with-
out the need of external components. During a “byte write”,
the address and data are latched internally, freeing the micro-
processor address and data bus for other operations. Fol-
lowing 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.
2004 Microchip Technology Inc.
DS11109K-page 1