1996 Microchip Technology Inc. DS11126F-page 1

FEATURES

• Fast Read Access Time—150 ns
• CMOS Technology for Low Power Dissipation
- 30 mA Active
- 100

m

A Standby
• Fast Byte Write Time—200

m

s or 1 ms
• Data Retention >200 years
• Endurance - Minimum 10

4

Erase/Write Cycles
- Automatic Write Operation
- Internal Control Timer
- Auto-Clear Before Write Operation
- On-Chip Address and Data Latches
• Data Polling
• Chip Clear Operation
• Enhanced Data Protection
-VCC

Detector
- Pulse Filter
- Write Inhibit
• 5-Volt-Only Operation
• Organized 512x8 JEDEC standard pinout
- 24-pin Dual-In-Line Package
- 32-pin PLCC Package
• Available for Extended Temperature Ranges:
- Commercial: 0˚C to +70˚C
- Industrial: -40˚C to +85˚C

DESCRIPTION

The Microchip Technology Inc. 28C04A is a CMOS 4K
non-volatile electrically Erasable and Programmable
Read Only Memory (EEPROM). The 28C04A 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 microprocessor 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 con-
trol timer. To determine when a write cycle is complete,
the 28C04A uses Data polling. Data polling allows the
user to read the location last written to when the write
operation is complete. CMOS design and processing
enables this part to be used in systems where reduced
power consumption and reliability are required. A com-
plete family of packages is offered to provide the utmost
flexibility in applications.

PACKAGE TYPES

BLOCK DIAGRAM
• 1
2
3
4
5
6
7
8
9
10
11
12

24
23
22
21
20
19
18
17
16
15
14
13
A7
A6
A5
A4
A3
A2
A1
A0
I/O0
I/O1
I/O2
V
Vcc
A8
NC
WE
OE
NC
CE
I/O7
I/O6
I/O5
I/O4
I/O3
SS
A6
A5
A4
A3
A2
A1
A0
NC
I/O0
A8
NC
NC
NC
OE
NC
CE
I/O7
I/O6
A7 NC NC NU Vcc WE NC
I/O1 I/O2
Vss
NU
I/O3 I/O4 I/O5
14 15 16 17 18 19 20
4 3 2 1
32 31 30
29
28
27
26
25
24
23
22
21
5
6
7
8
9
10
11
12
13
DIP
PLCC
28C04A
• Pin 1 indicator on PLCC on top of package
28C04A
I/O0 I/O7
Input/Output
Buffers
Chip Enable/
Output Enable
Control Logic
CE
OE
Data Protection
Circuitry
A8
Y Gating
4K bit
Cell Matrix
X
Decoder
Y
Decoder
A0
Data
Poll
Auto Erase/Write
Timing
VCC
VSS
WE
L
a
t
c
h
e
s
Program Voltage
Generation

28C04A

4K (512 x 8) CMOS EEPROM

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