– On-Chip Address and Data Latches
– Self-Timed Write Cycle with Auto-Clear
■ Fast Write Cycle Time:
– 5ms Max
■ CMOS and TTL Compatible I/O
■ Hardware and Software Write Protection
DESCRIPTION
The CAT28C65B is a fast, low power, 5V-only CMOS
parallel E2PROM organized as 8K x 8-bits. It requires a
simple interface for in-system programming. On-chip
address and data latches, self-timed write cycle with
auto-clear and VCC power up/down write protection
eliminate additional timing and protection hardware.
DATA Polling, a RDY/BUSY pin and Toggle status bits
signal the start and end of the self-timed write cycle.
■ Commercial, Industrial and Automotive
Temperature Ranges
■ Automatic Page Write Operation:
– 1 to 32 Bytes in 5ms
– Page Load Timer
■ End of Write Detection:
– Toggle Bit
DATADATA
–
DATA Polling
DATADATA
– RDY/
■ 100,000 Program/Erase Cycles
■ 100 Year Data Retention
BUSYBUSY
BUSY
BUSYBUSY
Additionally, the CAT28C65B features hardware and
software write protection.
The CAT28C65B is manufactured using Catalyst’s advanced CMOS floating gate technology. It is designed to
endure 100,000 program/erase cycles and has a data
retention of 100 years. The device is available in JEDECapproved 28-pin DIP, 28-pin TSOP, 28-pin SOIC or 32pin PLCC packages.
Temperature Under Bias ................. –55°C to +125°C
Storage Temperature....................... –65°C to +150°C
*COMMENT
Stresses above those listed under “Absolute Maximum
Ratings” may cause permanent damage to the device.
These are stress ratings only, and functional operation
Voltage on Any Pin with
Respect to Ground
(2)
........... –2.0V to +VCC + 2.0V
VCC with Respect to Ground ............... –2.0V to +7.0V
of the device at these or any other conditions outside of
those listed in the operational sections of this specification is not implied. Exposure to any absolute maximum
rating for extended periods may affect device performance and reliability.
Lead Soldering Temperature (10 secs) ............ 300°C
(3)
Output Short Circuit Current
........................ 100 mA
RELIABILITY CHARACTERISTICS
SymbolParameterMin.Max.UnitsTest Method
N
T
V
I
LTH
END
DR
ZAP
(1)
(1)
(1)
(1)(4)
Endurance10
Data Retention100YearsMIL-STD-883, Test Method 1008
ESD Susceptibility2000VoltsMIL-STD-883, Test Method 3015
Latch-Up100mAJEDEC Standard 17
ACTIVE
Standby, and Write InhibitHXXHigh-ZSTANDBY
Read and Write InhibitXHHHigh-ZACTIVE
CAPACITANCE TA = 25°C, F = 1.0 MHZ, VCC = 5V
SymbolTestMax.UnitsConditions
(1)
C
I/O
(1)
C
IN
Note:
(1) This parameter is tested initially and after a design or process change that affects the parameter.
(2) The minimum DC input voltage is –0.5V. During transitions, inputs may undershoot to –2.0V for periods of less than 20 ns. Maximum DC
voltage on output pins is VCC +0.5V, which may overshoot to VCC +2.0V for periods of less than 20 ns.
(3) Output shorted for no more than one second. No more than one output shorted at a time.
(4) Latch-up protection is provided for stresses up to 100mA on address and data pins from –1V to VCC +1V.
Input/Output Capacitance10pFV
I/O
= 0V
Input Capacitance6pFVIN = 0V
3
Doc. No. 25036-00 2/98
CAT28C65B
D.C. OPERATING CHARACTERISTICS
V
= 5V ±10%, unless otherwise specified.
CC
Limits
SymbolParameterMin.Typ.Max.UnitsTest Conditions
I
CC
I
CCC
(1)
VCC Current (Operating, TTL)30mACE = OE = VIL,
f = 1/tRC min, All I/O’s Open
VCC Current (Operating, CMOS)25mACE = OE = V
ILC
f = 1/tRC min, All I/O’s Open
,
Note:
(1) V
(2) V
I
SB
I
SBC
I
LI
I
LO
V
V
V
V
V
IH
IL
OH
OL
WI
ILC
IHC
VCC Current (Standby, TTL)1mACE = VIH, All I/O’s Open
(2)
VCC Current (Standby, CMOS)100µACE = V
Input Leakage Current–1010µAVIN = GND to V
Output Leakage Current–1010µAV
Read Cycle Time120150ns
CE Access Time120150ns
Address Access Time120150ns
OE Access Time6070ns
CE Low to Active Output00ns
OE Low to Active Output00ns
CE High to High-Z Output5050ns
OE High to High-Z Output5050ns
Output Hold from Address Change00ns
CAT28C65B
Figure 1. A.C. Testing Input/Output Waveform(3)
2.4 V
INPUT PULSE LEVELSREFERENCE POINTS
0.45 V
2.0 V
0.8 V
Figure 2. A.C. Testing Load Circuit (example)
1.3V
1N914
3.3K
DEVICE
UNDER
TEST
CL INCLUDES JIG CAPACITANCE
Note:
(1) This parameter is tested initially and after a design or process change that affects the parameter.
(2) Output floating (High-Z) is defined as the state when the external data line is no longer driven by the output buffer.
(3) Input rise and fall times (10% and 90%) < 10 ns.
CL = 100 pF
OUT
5096 FHD F03
5096 FHD F04
5
Doc. No. 25036-00 2/98
CAT28C65B
A.C. CHARACTERISTICS, Write Cycle
V
= 5V ±10%, unless otherwise specified.
CC
28C65B-1228C65B-15
SymbolParameterMin.Max.Min.Max.Units
t
WC
Write Cycle Time55ms
t
AS
t
AH
t
CS
t
CH
(2)
t
CW
t
OES
t
OEH
(2)
t
WP
t
RB
t
DS
t
DH
(1)
t
INIT
(1)(3)
t
BLC
Note:
(1)This parameter is tested initially and after a design or process change that affects the parameter.
(2)A write pulse of less than 20ns duration will not initiate a write cycle.
(3)A timer of duration t
however a transition from HIGH to LOW within t
Address Setup Time00ns
Address Hold Time100100ns
CE Setup Time00ns
CE Hold Time00ns
CE Pulse Time110110ns
OE Setup Time00ns
OE Hold Time00ns
OE Pulse Width110110ns
OE Low to RDY/BUSY Low120120ns
Data Setup Time6060ns
Data Hold Time00ns
Write Inhibit Period After Power-up510510ms
Byte Load Cycle Time.05100.05100µs
max. begins with every LOW to HIGH transition of WE. If allowed to time out, a page or byte write will begin;
BLC
max. stops the timer.
BLC
Doc. No. 25036-00 2/98 P-1
6
CAT28C65B
DEVICE OPERATION
Read
Data stored in the CAT28C65B is transferred to the data
bus when WE is held high, and both OE and CE are held
low. The data bus is set to a high impedance state when
either CE or OE goes high. This 2-line control architec-
Figure 3. Read Cycle
t
RC
ADDRESS
t
CE
CE
t
OE
OE
V
IH
WE
DATA OUTDA TA V ALIDDA TA V ALID
HIGH-Z
t
LZ
t
OLZ
ture can be used to eliminate bus contention in a system
environment.
Byte Write
A write cycle is executed when both CE and WEare low,
and OE is high. Write cycles can be initiated using eitherWE or CE, with the address input being latched on the
t
OHZ
t
OH
t
AA
t
HZ
28C65B F06
Figure 4. Byte Write Cycle [
ADDRESS
t
AS
CE
OE
WE
RDY/BUSY
DATA OUT
DATA IN
HIGH-ZHIGH-Z
WEWE
WE Controlled]
WEWE
t
AH
t
CS
t
OES
t
RB
t
WP
HIGH-Z
DATA VALID
t
CH
t
OEH
t
BLC
t
WC
t
DS
t
DH
5099 FHD F06
7
Doc. No. 25036-00 2/98
CAT28C65B
falling edge of WE or CE, whichever occurs last. Data,
conversely, is latched on the rising edge of WE or CE,
whichever occurs first. Once initiated, a byte write cycle
automatically erases the addressed byte and the new
data is written within 5 ms.
Page Write
The page write mode of the CAT28C65B (essentially an
extended BYTE WRITE mode) allows from 1 to 32 bytes
of data to be programmed within a single E
2
PROM write
Figure 5. Byte Write Cycle [CE Controlled]
ADDRESS
CE
OE
WE
t
t
CS
AS
t
OES
t
AH
t
CW
cycle. This effectively reduces the byte-write time by a
factor of 32.
Following an initial WRITE operation (WE pulsed low, for
tWP, and then high) the page write mode can begin by
issuing sequential WE pulses, which load the address
and data bytes into a 32 byte temporary buffer. The page
address where data is to be written, specified by bits A
to A12, is latched on the last falling edge of WE. Each
byte within the page is defined by address bits A0 to A
t
WC
t
BLC
t
OEH
t
CH
5
4
t
RB
RDY/BUSY
DATA OUT
DATA IN
HIGH-ZHIGH-Z
Figure 6. Page Mode Write Cycle
OE
CE
WE
ADDRESS
t
WP
HIGH-Z
DATA VALID
t
DS
t
BLC
t
DH
5099 FHD F07
I/O
Doc. No. 25036-00 2/98 P-1
LAST BYTE
BYTE 0BYTE 1BYTE 2BYTE nBYTE n+1BYTE n+2
8
t
WC
5096 FHD F10
CAT28C65B
(which can be loaded in any order) during the first and
subsequent write cycles. Each successive byte load
cycle must begin within t
BLC MAX
of the rising edge of the
preceding WE pulse. There is no page write window
limitation as long as WE is pulsed low within t
BLC MAX
Upon completion of the page write sequence, WE must
stay high a minimum of t
BLC MAX
for the internal automatic program cycle to commence. This programming
cycle consists of an erase cycle, which erases any data
that existed in each addressed cell, and a write cycle,
which writes new data back into the cell. A page write will
only write data to the locations that were addressed and
will not rewrite the entire page.
DATA Polling
DATA polling is provided to indicate the completion of
write cycle. Once a byte write or page write cycle is
initiated, attempting to read the last byte written will
output the complement of that data on I/O7 (I/O0–I/O
Figure 7. DATA Polling
ADDRESS
are indeterminate) until the programming cycle is complete. Upon completion of the self-timed write cycle, all
I/O’s will output true data during a read cycle.
.
Toggle Bit
In addition to the DATA Polling feature, the device offers
an additional method for determining the completion of
a write cycle. While a write cycle is in progress, reading
data from the device will result in I/O
one and zero. However, once the write is complete, I/O
toggling between
6
6
stops toggling and valid data can be read from the
device.
Ready/BUSY (RDY/BUSY)
The RDY/BUSY pin is an open drain output which
indicates device status during programming. It is pulled
low during the write cycle and released at the end of
programming. Several devices may be OR-tied to the
same RDY/BUSY line.
6
CE
WE
OE
I/O
7
Figure 8. Toggle Bit
WE
CE
OE
t
OEH
D
= XD
IN
t
OEH
t
OE
t
OE
t
WC
= XD
OUT
OUT
= X
t
OES
t
OES
28C65B F10
I/O
6
(1)(1)
t
WC
9
28C65B F11
Doc. No. 25036-00 2/98
CAT28C65B
WRITE DATA: AA
ADDRESS:1555
WRITE DATA: 55
ADDRESS:0AAA
WRITE DATA: 80
ADDRESS:1555
WRITE DATA: AA
ADDRESS:1555
WRITE DATA: 55
ADDRESS:0AAA
WRITE DATA: 20
ADDRESS:1555
HARDWARE DATA PROTECTION
The following is a list of hardware data protection features that are incorporated into the CAT28C65B.
(1) VCC sense provides for write protection when V
CC
falls below 3.5V min.
(2) A power on delay mechanism, t
(see AC charac-
INIT
teristics), provides a 5 to 10 ms delay before a write
sequence, after VCC has reached 3.5V min.
(3) Write inhibit is activated by holding any one of OE
low, CE high or WE high.
Figure 9. Write Sequence for Activating Software
Data Protection
WRITE DATA:AA
ADDRESS:1555
WRITE DATA:55
ADDRESS:0AAA
(4) Noise pulses of less than 20 ns on the WE or CE
inputs will not result in a write cycle.
SOFTWARE DATA PROTECTION
The CAT28C65B features a software controlled data
protection scheme which, once enabled, requires a data
algorithm to be issued to the device before a write can be
performed. The device is shipped from Catalyst with the
software protection NOT ENABLED (the CAT28C65B is
in the standard operating mode).
Figure 10. Write Sequence for Deactivating
Software Data Protection
WRITE DATA:A0
ADDRESS:1555
SOFTWARE DATA
PROTECTION A CTIV A TED
WRITE DATA:XX
TO ANY ADDRESS
WRITE LAST BYTE
TO
LAST ADDRESS
(1)
28C65B F125094 FHD F09
Note:
(1)Write protection is activated at this point whether or not any more writes are completed. Writing to addresses must occur within t
Max., after SDP activation.
Doc. No. 25036-00 2/98 P-1
BLC
10
CAT28C65B
To activate the software data protection, the device must
be sent three write commands to specific addresses with
specific data (Figure 9). This sequence of commands
(along with subsequent writes) must adhere to the page
write timing specifications (Figure 11). Once this is done,
all subsequent byte or page writes to the device must be
preceded by this same set of write commands. The data
protection mechanism is activated until a deactivate
sequence is issued regardless of power on/off transitions. This gives the user added inadvertent write protection on power-up in addition to the hardware protection provided.
Figure 11. Software Data Protection Timing
DATA
ADDRESS
CE
WE
AA
1555
55
0AAA
Figure 12. Resetting Software Data Protection Timing
DATA
ADDRESS
AA
1555
55
0AAA
80
1555
To allow the user the ability to program the device with
an E2PROM programmer (or for testing purposes) there
is a software command sequence for deactivating the
data protection. The six step algorithm (Figure 10) will
reset the internal protection circuitry, and the device will
return to standard operating mode (Figure 12 provides
reset timing). After the sixth byte of this reset sequence
has been issued, standard byte or page writing can
commence.
t
AA
1555
A0
1555
t
WP
55
0AAA
t
BLC
BYTE OR
PAGE
WRITES
ENABLED
20
1555
t
WC
WC
5094 FHD F13
SDP
RESET
CE
WE
ORDERING INFORMATION
PrefixDevice #Suffix
CAT
28C65B
Product
Number
Optional
Company
ID
N
Temperature Range
Blank = Commercial (0˚C to +70˚C)
I = Industrial (-40˚C to +85˚C)
A = Automotive (-40˚ to +105˚C)*