1998 Microchip Technology Inc.
DS11126G-page 1
FEATURES
Fast Read Access Time--150 ns
CMOS Technology for Low Power Dissipation
- 30 mA Active
- 100
A Standby
Fast Byte Write Time--200
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
- V
CC
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: 0C to +70C
- Industrial: -40C to +85C
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 inter-
nally, 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 automati-
cally clear and write the latched data using an internal
control timer. To determine when a write cycle is com-
plete, 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 pro-
cessing 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.
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
28
C
04A
Pin 1 indicator on PLCC on top of package
28C
0
4
A
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
V
CC
V
SS
WE
L
a
t
c
h
e
s
Program Voltage
Generation
28C04A
4K (512 x 8) CMOS EEPROM
28C04A
DS11126G-page 2
1998 Microchip Technology Inc.
1.0
ELECTRICAL CHARACTERISTICS
1.1
MAXIMUM RATINGS*
V
CC
and input voltages w.r.t. V
SS
....... -0.6V to + 6.25V
Voltage on OE w.r.t. V
SS
...................... -0.6V to +13.5V
Output Voltage w.r.t. V
SS
.................-0.6V to V
CC
+0.6V
Storage temperature ..........................-65C to +125C
Ambient temp. with power applied .......-50C to +95C
*Notice: Stresses above those listed under "Maximum Ratings"
may cause permanent damage to the device. This is a stress rat-
ing only and functional operation of the device at those or any
other conditions above those indicated in the operation listings of
this specification is not implied. Exposure to maximum rating con-
ditions for extended periods may affect device reliability.
TABLE 1-1:
PIN FUNCTION TABLE
Name
Function
A0 - A8
Address Inputs
CE
Chip Enable
OE
Output Enable
WE
Write Enable
I/O0 - I/O7
Data Inputs/Outputs
V
CC
+5V Power Supply
V
SS
Ground
NC
No Connect; No Internal Connection
NU
Not Used; No External Connection is
Allowed
TABLE 1-2:
READ/WRITE OPERATION DC CHARACTERISTICS
V
CC
= +5V
10%
Commercial (C): Tamb =
0C to +70C
Industrial (I): Tamb = -40C to +85C
Parameter
Status
Symbol
Min
Max
Units
Conditions
Input Voltages
Logic `1'
Logic `0'
V
IH
V
IL
2.0
-0.1
V
CC
+1
0.8
V
V
Input Leakage
I
LI
-10
10
A
V
IN
= -0.1V to V
CC
+1
Input Capacitance
C
IN
10
pF
V
IN
= 0V; Tamb = 25C;
f = 1 MHz
Output Voltages
Logic `1'
Logic `0'
V
OH
V
OL
2.4
0.45
V
V
I
OH
= -400
A
I
OL
= 2.1 mA
Output Leakage
I
LO
-10
10
A
V
OUT
= -0.1V
TO
V
CC
+ 0.1V
Output Capacitance
C
OUT
12
pF
V
IN
= 0V; T
AMB
= 25C;
f = 1 MHz
Power Supply Current, Active
TTL input
I
CC
30
mA
f = 5 MHz (Note 1)
V
CC
= 5.5V
Power Supply Current, Standby
TTL input
TTL input
CMOS input
I
CC
(
S
)
TTL
I
CC
(
S
)
TTL
I
CC
(
S
)
CMOS
2
3
100
mA
mA
A
CE = V
IH
(0C to +70C)
CE = V
IH
(-40C to +85C)
CE = V
CC
-0.3 to V
CC
+1
OE = V
CC
All inputs equal V
CC
or V
SS
Note 1: AC power supply current above 5 MHz; 1 mA/MHz.
1998 Microchip Technology Inc.
DS11126G-page 3
28C04A
TABLE 1-3:
READ OPERATION AC CHARACTERISTICS
FIGURE 1-1:
READ WAVEFORMS
AC Testing Waveform:
V
IH
= 2.4V; V
IL
= 0.45V; V
OH
= 2.0V; V
OL
= 0.8V
Output Load:
1 TTL Load + 100 pF
Input Rise and Fall Times: 20 ns
Ambient Temperature:
Commercial (C): Tamb =
0C to +70C
Industrial
(I):
Tamb =
-40C to +85C
Parameter
Sym
28C04A-15
28C04A-20
28C04A-25
Units
Conditions
Min
Max
Min
Max
Min
Max
Address to Output Delay
t
ACC
150
200
250
ns
OE = CE = V
IL
CE to Output Delay
t
CE
150
200
250
ns
OE = V
IL
OE to Output Delay
t
OE
70
80
100
ns
CE = V
IL
CE to OE High Output Float
t
OFF
0
50
0
55
0
70
ns
Output Hold from Address, CE
or OE, whichever occurs first
t
OH
0
0
0
ns
Endurance
--
1M
--
1M
--
1M
--
cycles 25C, Vcc =
5.0V, Block
Mode (Note)
Note: This parameter is not tested but guaranteed by characterization. For endurance estimates in a specific appli-
cation, please consult the Total Endurance Model which can be obtained on our BBS or website.
28C04A
DS11126G-page 4
1998 Microchip Technology Inc.
TABLE 1-4:
BYTE WRITE AC CHARACTERISTICS
FIGURE 1-2:
PROGRAMMING WAVEFORMS
AC Testing Waveform:
V
IH
= 2.4V; V
IL
= 0.45V; V
OH
= 2.0V; V
OL
= 0.8V
Output Load:
1 TTL Load + 100 pF
Input Rise/Fall Times:
20 nsec
Ambient Temperature:
Commercial (C): Tamb= 0C to 70C
Industrial
(I):
Tamb= -40C to 85C
Parameter
Symbol
Min
Max
Units
Remarks
Address Set-Up Time
t
AS
10
ns
Address Hold Time
t
AH
50
ns
Data Set-Up Time
t
DS
50
ns
Data Hold Time
t
DH
10
ns
Write Pulse Width
t
WPL
100
ns
Note 1
Write Pulse High Time
t
WPH
50
ns
OE Hold Time
t
OEH
10
ns
OE Set-Up Time
t
OES
10
ns
Data Valid Time
t
DV
1000
ns
Note 2
Write Cycle Time (28C04A)
t
WC
1
ms
0.5 ms typical
Write Cycle Time (28C04AF)
t
WC
200
s
100
s typical
Note 1: A write cycle can be initiated be CE or WE going low, whichever occurs last. The data is latched on the pos-
itive edge of CE or WE, whichever occurs first.
2: Data must be valid within 1000ns max. after a write cycle is initiated and must be stable at least until t
DH
after the positive edge of WE or CE, whichever occurs first.
t
AS
t
AH
t
WPL
t
DS
t
DH
t
OES
t
OEH
t
DV
Address
CE, WE
Data In
OE
V
IH
V
IL
V
IH
V
IL
V
IH
V
IL
V
IH
V
IL
1998 Microchip Technology Inc.
DS11126G-page 5
28C04A
FIGURE 1-3:
DATA POLLING WAVEFORMS
FIGURE 1-4:
CHIP CLEAR WAVEFORMS
Address Valid
Last Written
Address Valid
t
ACC
t
CE
t
WPL
t
WPH
t
DV
t
WC
t
OE
True Data Out
Data In
Valid
V
IH
V
IL
Data
OE
WE
CE
Address
I/O7 Out
V
IH
V
IL
V
IH
V
IL
V
IH
V
IL
V
IH
V
IL
V
H
V
IH
CE
OE
WE
t
S
t
H
t
W
t
S
= = 1
s
t
H
= 10ms
t
W
V
IH
V
IL
V
IH
V
IL
= 12.0V
0.5V
V
H
28C04A
DS11126G-page 6
1998 Microchip Technology Inc.
2.0
DEVICE OPERATION
The Microchip Technology Inc. 28C04A has four basic
modes of operation--read, standby, write inhibit, and
byte write--as outlined in the following table.
2.1
Read Mode
The 28C04A has two control functions, both of which
must be logically satisfied in order to obtain data at the
outputs. Chip enable (CE) is the power control and
should be used for device selection. Output Enable
(OE) is the output control and is used to gate data to the
output pins independent of device selection. Assuming
that addresses are stable, address access time (t
ACC
)
is equal to the delay from CE to output (t
CE
). Data is
available at the output tOE after the falling edge of OE,
assuming that CE has been low and addresses have
been stable for at least t
ACC
-t
OE
.
2.2
Standby Mode
The 28C04A is placed in the standby mode by applying
a high signal to the CE input. When in the standby
mode, the outputs are in a high impedance state, inde-
pendent of the OE input.
2.3
Data Protection
In order to ensure data integrity, especially during criti-
cal power-up and power-down transitions, the following
enhanced data protection circuits are incorporated:
First, an internal V
CC
detect (3.3 volts typical) will inhibit
the initiation of non-volatile programming operation
when V
CC
is less than the V
CC
detect circuit trip.
Second, there is a WE filtering circuit that prevents WE
pulses of less than 10 ns duration from initiating a write
cycle.
Third, holding WE or CE high or OE low, inhibits a write
cycle during power-on and power-off (V
CC
).
Operation
Mode
CE
IE
WE
I/O
Read
L
L
H
D
OUT
Standby
H
X
X
High Z
Write Inhibit
H
X
X
High Z
Write Inhibit
X
L
X
High Z
Write Inhibit
X
X
H
High Z
Byte Write
L
H
L
D
IN
Byte Clear
Automatic Before Each "Write"
X = Any TTL level.
2.4
Write Mode
The 28C04A has a write cycle similar to that of a Static
RAM. The write cycle is completely self-timed and initi-
ated by a low going pulse on the WE pin. On the falling
edge of WE, the address information is latched. On ris-
ing edge, the data and the control pins (CE and OE) are
latched.
2.5
Data Polling
The 28C04A features Data polling to signal the comple-
tion of a byte write cycle. During a write cycle, an
attempted read of the last byte written results in the
data complement of I/O7 (I/O0 to I/O6 are indetermin-
able). After completion of the write cycle, true data is
available. Data polling allows a simple read/compare
operation to determine the status of the chip eliminating
the need for external hardware.
2.6
Chip Clear
All data may be cleared to 1's in a chip clear cycle by
raising OE to 12 volts and bringing the WE and CE low.
This procedure clears all data.
28C04A
28C04A Product Identification System
To order or to obtain information, e.g., on pricing or delivery, please use the listed part numbers, and refer to the factory or the listed
sales offices.
Package:
L = Plastic Leaded Chip Carrier (PLCC)
P = Plastic DIP (600mill)
Temperature
Blank = 0
C to +70
C
Range:
I
= -40
C to +85
C
Access Time:
15
150 ns
20
200 ns
25
250 ns
Shipping:
Blank
Tube
T
Tape and Reel "L" only
Option:
Blank = twc = 1ms
F = twc = 200
s
Device:
28C04A
512 x 8 CMOS EEPROM
28C04A
F T
15
I /P
1998 Microchip Technology Inc.
DS11126G-page 7
28C04A
DS11126G-page 8
1998 Microchip Technology Inc.
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