Obsolete Device
28C04A
4K (512 x 8) CMOS EEPROM
32 Vcc
31 WE
29 A8
6
28 NC
7
27 NC
8
9
10
11
26 NC
25 OE
24 NC
23 CE
20
19
18
17
21 I/O6
15
22 I/O7
13
14
12
• Pin 1 indicator on PLCC on top of package
BLOCK DIAGRAM
I/O0
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
control 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 complete family of packages is offered to
provide the utmost flexibility in applications.
2004 Microchip Technology Inc.
Vcc
A8
NC
WE
OE
NC
CE
I/O7
I/O6
I/O5
I/O4
I/O3
5
28C04A
A6
A5
A4
A3
A2
A1
A0
NC
I/O0
2 NC
1 NU
PLCC
24
23
22
21
20
19
18
17
16
15
14
13
30 NC
•1
2
3
4
5
6
7
8
9
10
11
12
4 A7
3 NC
A7
A6
A5
A4
A3
A2
A1
A0
I/O0
I/O1
I/O2
VSS
16
DIP
28C04A
• 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
• Endurance - Minimum 104 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
PACKAGE TYPES
I/O1
I/O2
Vss
NU
I/O3
I/O4
I/O5
FEATURES
VSS
VCC
Data Protection
Circuitry
Chip Enable/
Output Enable
Control Logic
CE
OE
WE
I/O7
Auto Erase/Write
Timing
Data
Poll
Input/Output
Buffers
Program Voltage
Generation
A0
L
a
t
c
h
e
s
Y
Decoder
Y Gating
X
Decoder
4K bit
Cell Matrix
A8
DS11126H-page 1
