28C64A_04 Datasheet, PDF (1/10 Pages) Microchip Technology – 64K (8K x 8) CMOS EEPROM

Obsolete Device
28C64A
64K (8K x 8) CMOS EEPROM
FEATURES
• Fast Read Access Time—150 ns
• CMOS Technology for Low Power Dissipation
- 30 mA Active
- 100 µA Standby
• 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
- Auto-Clear Before Write Operation
- On-Chip Address and Data Latches
• Data Polling
• Ready/Busy
• Chip Clear Operation
• Enhanced Data Protection
- VCC Detector
- Pulse Filter
- Write Inhibit
• 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 SOIC Package
• Available for Extended Temperature Ranges:
- Commercial: 0°C to +70°C
- Industrial: -40°C to +85°C
DESCRIPTION
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.
PACKAGE TYPES
RDY/BSY • 1
A12 2
A7 3
A6 4
A5 5
A4 6
A3 7
A2 8
A1 9
A0 10
I/O0 11
I/O1 12
I/O2 13
VSS 14
28 Vcc
27 WE
26 NC
25 A8
24 A9
A6 5
A5 6
23 A11 A4 7
22 OE A3 8
21 A10 ^{A2 9}
20 CE ^{A1 10}
19 I/O7 ^{A0 11}
18
I/O6
NC
I/O0
12
13
17 I/O5
16 I/O4
15 I/O3
29 A8
28 A9
27 A11
26 NC
25 OE
24 A10
23 CE
22 I/O7
21 I/O6
• Pin 1 indicator on PLCC on top of package
BLOCK DIAGRAM
I/O0
I/O7
VSS
VCC
CE
OE
WE
Rdy/
Busy
A0
A12
Data Protection
Circuitry
Chip Enable/
Output Enable
Control Logic
Auto Erase/Write
Timing
Program Voltage
Generation
Data
Poll
Y
L
Decoder
a
t
c
h
e
X
s
Decoder
Input/Output
Buffers
Y Gating
16K bit
Cell Matrix
 2004 Microchip Technology Inc.
DS11109K-page 1