28C64A
64K (8K x 8) CMOS EEPROM
FEATURES
• Fast Read Access Time—150 ns
• CMOS Technology for Low Power Dissipation
- 30 mA Active
- 100
µ
A Standby
• Fast Byte Write Time—200
µ
s 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
- V
CC
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 Thin Small Outline Package (TSOP)
8x20mm
- 28-pin Very Small Outline Package (VSOP)
8x13.4mm
• Available for Extended Temperature Ranges:
- Commercial: 0˚C to +70˚C
PACKAGE TYPES
RDY/BSY
A12
A7
A6
A5
A4
A3
A2
A1
A0
I/O0
I/O1
I/O2
V
SS
•1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
Vcc
WE
NC
A8
A6
5
A9
A5
6
A11 A4
7
A3
8
OE
A10 A2
9
A1
10
CE
A0
11
I/O7
NC
12
I/O6
I/O0
13
I/O5
I/O4
I/O3
2
RDY/BSY
1
NU
4
A7
3
A12
32
Vcc
31
WE
18
19
30
NC
29
A8
28
A9
27
A11
26
NC
25
OE
24
A10
23
CE
22
I/O7
21
I/O6
20
14
15
16
• Pin 1 indicator on PLCC on top of package
OE
A11
A9
A8
NC
WE
Vcc
RDY/BSY
A12
A7
A6
A5
A4
A3
OE
A11
A9
A8
NC
WE
V
CC
RDY/BSY
A12
A7
A6
A5
A4
A3
1
2
3
4
5
6
7
8
9
10
11
12
13
14
22
23
24
25
26
27
28
1
2
3
4
5
6
7
I/O1
I/O2
Vss
NU
I/O3
I/O4
I/O5
17
DIP/SOIC
PLCC
28
27
26
25
24
23
22
21
20
19
18
17
16
15
21
20
19
18
17
16
15
14
13
12
11
10
9
8
A10
CE
I/07
I/06
I/05
I/04
I/03
Vss
I/02
I/01
I/00
A0
A1
A2
A10
CE
I/O7
I/O6
I/O5
I/O4
I/O3
V
SS
I/O2
I/O1
I/O0
A0
A1
A2
TSOP
VSOP
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 without
the need of external components. During a “byte write”, the
address and data are latched internally, freeing the micropro-
cessor 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 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
BLOCK DIAGRAM
I/O0
I/O7
V
SS
V
CC
CE
OE
WE
Rdy/
Busy
Data Protection
Circuitry
Chip Enable/
Output Enable
Control Logic
Auto Erase/Write
Timing
Data
Poll
Input/Output
Buffers
Program Voltage
Generation
A0
L
a
t
c
h
e
s
A12
Y
Decoder
Y Gating
X
Decoder
16K bit
Cell Matrix
©
1996 Microchip Technology Inc.
DS11109H-page 1
This document was created with FrameMaker 4 0 4
28C64A
1.0
1.1
ELECTRICAL CHARACTERISTICS
MAXIMUM RATINGS*
TABLE 1-1:
Name
A0 - A12
CE
OE
WE
I/O0 - I/O7
RDY/Busy
V
CC
V
SS
NC
NU
PIN FUNCTION TABLE
Function
Address Inputs
Chip Enable
Output Enable
Write Enable
Data Inputs/Outputs
Ready/Busy
+5V Power Supply
Ground
No Connect; No Internal Connection
Not Used; No External Connection is
Allowed
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
Voltage on A9 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 .......................... -65˚C to +125˚C
Ambient temp. with power applied ....... -50˚C to +95˚C
*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 1-2:
READ/WRITE OPERATION DC CHARACTERISTIC
V
CC
= +5V
±
10%
Commercial (C): Tamb = 0˚C to +70˚C
Industrial
(I): Tamb = -40˚C to +85˚C
Parameter
Input Voltages
Input Leakage
Input Capacitance
Output Voltages
Output Leakage
Output Capacitance
Power Supply Current, Active
Power Supply Current, Standby
Status
Logic ‘1’
Logic ‘0’
—
—
Logic ‘1’
Logic ‘0’
—
—
TTL input
Symbol
V
IH
V
IL
I
LI
C
IN
V
OH
V
OL
I
LO
C
OUT
I
CC
Min
2.0
-0.1
-10
—
2.4
Max
Vcc+1
0.8
10
10
Units
V
V
µ
A
pF
V
V
µ
A
pF
mA
mA
mA
µ
A
Conditions
V
IN
= -0.1V to Vcc +1
V
IN
= 0V; Tamb = 25˚C;
f = 1 MHz (Note 2)
I
OH
= -400
µ
A
I
OL
= 2.1 mA
V
OUT
= -0.1V to Vcc
+0.1V
V
IN
= 0V; Tamb = 25˚C;
f = 1 MHz (Note 2)
f = 5 MHz (Note 1)
V
CC
= 5.5V
CE = V
IH
(0˚C to +70˚C)
CE = V
IH
(-40˚C to +85˚C)
CE = V
CC
-0.3 to Vcc +1
0.45
-10
—
—
—
10
12
30
2
3
100
I
CC
(
S
)
TTL
TTL input
TTL input
I
CC
(
S
)
TTL
CMOS input I
CC
(
S
)
CMOS
Note 1: AC power supply current above 5MHz: 2mA/MHz.
2: Not 100% tested.
DS11109H-page 2
©
1996 Microchip Technology Inc.
28C64A
TABLE 1-3:
READ OPERATION AC CHARACTERISTICS
AC Testing Waveform:
Output Load:
Input Rise and Fall Times:
Ambient Temperature:
28C64A
-15
V
IH
= 2.4V; V
IL
= 0.45V; V
OH
= 2.0V; V
OL
= 0.8V
1 TTL Load + 100 pF
20 ns
Commercial (C):
Tamb = 0˚C to +70˚C
Industrial
(I):
Tamb = -40˚C to +85˚C
28C64A
-20
28C64A
-25
Parameter
Address to Output Delay
CE to Output Delay
OE to Output Delay
CE or OE High to Output Float
Output Hold from Address, CE
or OE, whichever occurs first.
Endurance
Symbol
Min
t
ACC
t
CE
t
OE
t
OFF
t
OH
—
—
—
—
0
0
1M
Max
150
150
70
50
—
—
Min
—
—
—
0
0
1M
Max
200
200
80
55
—
—
Min
—
—
—
0
0
1M
Max
250
250
100
70
—
—
Units
ns
ns
ns
ns
ns
Conditions
OE = CE = V
IL
OE = V
IL
CE = V
IL
(Note 1)
(Note 1)
cycles 25
°
C, Vcc =
5.0V, Block
Mode (Note 2)
Note 1: Not 100% tested.
2: 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.
FIGURE 1-1:
V
IH
Address
V
IL
V
IH
CE
V
IL
READ WAVEFORMS
Address Valid
t
CE(2)
V
IH
OE
V
IL
V
OH
Data
V
OL
t
ACC
V
IH
WE
V
IL
Notes: (1) t
OFF
is specified for OE or CE, whichever occurs first
(2) OE may be delayed up to t
CE
- t
OE
after the falling edge of CE without impact on t
CE
(3) This parameter is sampled and is not 100% tested
t
OFF(1,3)
t
OE(2)
High Z
t
OH
Valid Output
High Z
©
1996 Microchip Technology Inc.
DS11109H-page 3
28C64A
TABLE 1-4:
BYTE WRITE AC CHARACTERISTICS
AC Testing Waveform:
Output Load:
Input Rise/Fall Times:
Ambient Temperature:
Parameter
Address Set-Up Time
Address Hold Time
Data Set-Up Time
Data Hold Time
Write Pulse Width
Write Pulse High Time
OE Hold Time
OE Set-Up Time
Data Valid Time
Time to Device Busy
Write Cycle Time (
28C64A
)
Write Cycle Time (
28C64A
F)
Symbol
t
AS
t
AH
t
DS
t
DH
t
WPL
t
WPH
t
OEH
t
OES
t
DV
t
DB
t
WC
t
WC
Min
10
50
50
10
100
50
10
10
—
2
—
—
V
IH
= 2.4V; V
IL
= 0.45V; V
OH
= 2.0V; V
OL
= 0.8V
1 TTL Load + 100 pF
20 ns
Commercial (C):
Tamb = 0˚C to +70˚C
Industrial
(I):
Tamb = -40˚C to +85˚C
Max
—
—
—
—
—
—
—
—
1000
50
1
200
Units
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ms
µ
s
0.5 ms typical
100
µ
s typical
Note 2
Note 1
Remarks
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 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.
FIGURE 1-2:
PROGRAMMING WAVEFORMS
V
IH
Address
V
IL
V
IH
CE, WE
V
IL
t
DV
Data In
V
IH
V
IL
t
OES
V
IH
OE
V
IL
t
OEH
V
OH
Rdy/Busy
V
OL
t
WC
t
DB
Busy
Ready
t
DS
t
AS
t
AH
t
WPL
t
DH
DS11109H-page 4
©
1996 Microchip Technology Inc.
28C64A
FIGURE 1-3:
V
IH
Address
V
IL
Address Valid
t
ACC
t
CE
t
WPH
DATA POLLING WAVEFORMS
Last Written
Address Valid
V
IH
CE
V
IL
V
IH
WE
V
IL
t
WPL
t
OE
V
IH
OE
V
IL
t
DV
V
IH
Data
V
IL
Data In
Valid
t
WC
I/O7 Out
True Data Out
FIGURE 1-4:
V
IH
CE
V
IL
V
H
OE
V
IH
V
IH
WE
V
IL
CHIP CLEAR WAVEFORMS
t
S
t
W
t
H
t
W
= 10ms
t
S
= t
H
= 1µs
V
H
= 12.0V
±0.5V
TABLE 1-5:
Mode
Chip Clear
Extra Row Read
Extra Row Write
Note:
SUPPLEMENTARY CONTROL
CE
V
IL
V
IL
*
OE
V
IH
V
IL
V
IH
WE
V
IL
V
IH
*
A9
X
A9 = V
H
A9 = V
H
V
CC
V
CC
V
CC
V
CC
Data Out
Data In
I/O
I
V
H
= 12.0V
±
0.5V.
*Pulsed per programming waveforms.
©
1996 Microchip Technology Inc.
DS11109H-page 5
Embedded System
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