CAT1021, CAT1022, CAT1023
Supervisory Circuits with I
2
C Serial 2k-bit CMOS
EEPROM, Manual Reset and Watchdog Timer
FEATURES
Precision Power Supply Voltage Monitor
— 5V, 3.3V and 3V systems
— Five threshold voltage options
Watchdog Timer
Active High or Low Reset
— Valid reset guaranteed at V
CC
= 1V
400kHz I C Bus
2.7V to 5.5V Operation
Low power CMOS technology
16-Byte Page Write Buffer
Built-in inadvertent write protection
— WP pin (CAT1021)
1,000,000 Program/Erase cycles
Manual Reset Input
100 year data retention
Industrial and extended temperature ranges
8-pin DIP, SOIC, TSSOP, MSOP or TDFN
(3 x 3mm foot-print) packages
— TDFN max height is 0.8mm
All supervisors have a 1.6 second watchdog timer circuit
that resets a system to a known state if software or a
hardware glitch halts or “hangs” the system. For the
CAT1021 and CAT1022, the watchdog timer monitors
the SDA signal. The CAT1023 has a separate watchdog
timer interrupt input pin, WDI.
The power supply monitor and reset circuit protect
memory and system controllers during power up/down
and against brownout conditions. Five reset threshold
voltages support 5V, 3.3V and 3V systems. If power
supply voltages are out of tolerance reset signals
become active, preventing the system microcontroller,
ASIC or peripherals from operating. Reset signals
become inactive typically 200 ms after the supply voltage
exceeds the reset threshold level. With both active high
and low reset signals, interface to microcontrollers and
¯¯¯¯¯¯
other ICs is simple. In addition, the RESET pin or a
separate input, ¯¯¯, can be used as an input for push-
MR
button manual reset capability.
The on-chip, 2k-bit EEPROM memory features a 16-byte
page. In addition, hardware data protection is provided
by a V
CC
sense circuit that prevents writes to memory
whenever V
CC
falls below the reset threshold or until V
CC
reaches the reset threshold during power up.
Available packages include an 8-pin DIP and surface
mount 8-pin SO, 8-pin TSSOP, 8-pin TDFN and 8-pin
MSOP packages. The TDFN package thickness is
0.8mm maximum. TDFN footprint options are 3 x 3mm.
2
DESCRIPTION
The CAT1021, CAT1022 and CAT1023 are complete
memory and supervisory solutions for microcontroller-
based systems. A 2k-bit serial EEPROM memory and a
system power supervisor with brown-out protection are
integrated together in low power CMOS technology.
Memory interface is via a 400kHz I
2
C bus.
The CAT1021 and CAT1023 provide a precision V
CC
sense circuit and two open drain outputs: one (RESET)
¯¯¯¯¯¯
drives high and the other (RESET) drives low whenever
V
CC
falls below the reset threshold voltage. The
¯¯¯¯¯¯
CAT1022 has only a RESET output and does not have
a Write Protect input. The CAT1021 also has a Write
Protect input (WP). Write operations are disabled if WP
is connected to a logic high.
For Ordering Information details, see page 19.
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
1
Doc. No. MD-3009 Rev. M
CAT1021, CAT1022, CAT1023
BLOCK DIAGRAM
EXTERNA LOAD
L
DOUT
ACK
VCC
VSS
WORDADDRESS
BUFFERS
COLUMN
DECODERS
SENSEAMPS
SHIFT REGISTERS
THRESHOLD VOLTAGE OPTION
Part Dash
Number
-45
-42
-30
-28
-25
2kbit
EEPROM
Minimum
Threshold
4.50
4.25
3.00
2.85
2.55
Maximum
Threshold
4.75
4.50
3.15
3.00
2.70
SDA
START/STOP
LOGIC
XDEC
WP
(CAT1021)
CONTR
OL
LOGIC
DATA IN STORAGE
HIGHVOLTAGE/
TIMING CONTR
OL
RESET Controller
Precision
MR
Vcc Monitor
STATE COUNTERS
SLAVE
ADDRESS
COMPARATORS
SCL
RESET
(CAT1021/23)
RESET
WDI
(CAT1023)
PIN CONFIGURATION
DIP Package (L)
SOIC Package (W)
TSSOP Package (Y)
MSOP Package (Z)
¯¯¯
MR
¯¯¯¯¯¯
RESET
WP
V
SS
¯¯¯
MR
¯¯¯¯¯¯
RESET
NC
V
SS
¯¯¯
MR
¯¯¯¯¯¯
RESET
RESET
V
SS
1
2
3
4
1
2
3
4
1
2
3
4
CAT1023
CAT1022
CAT1021
8
7
6
5
8
7
6
5
8
7
6
5
V
CC
RESET
SCL
SDA
V
CC
NC
SCL
SDA
V
CC
WDI
SCL
SDA
(Bottom View)
TDFN Package: 3mm x 3mm
0.8mm maximum height - (ZD4)
V
CC
8
RESET 7
CAT1021
SCL 6
SDA 5
V
CC
8
NC 7
CAT1022
SCL 6
SDA 5
V
CC
8
WDI 7
CAT1023
SCL 6
SDA 5
1
¯¯¯
MR
¯¯¯¯¯¯
2
RESET
3 WP
4 V
SS
1
¯¯¯
MR
¯¯¯¯¯¯
2
RESET
3 NC
4 V
SS
1
¯¯¯
MR
¯¯¯¯¯¯
2
RESET
3 RESET
4 V
SS
Doc. No. MD-3009 Rev. M
2
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT1021, CAT1022, CAT1023
PIN DESCRIPTION
¯¯¯¯¯¯
RESET/RESET:
RESET OUTPUT
(RESET CAT1021/23 Only)
¯¯¯¯¯¯
These are open drain pins and RESET can be used
as a manual reset trigger input. By forcing a reset
condition on the pin the device will initiate and
maintain a reset condition. The RESET pin must be
connected through a pull-down resistor, and the
¯¯¯¯¯¯
RESET pin must be connected through a pull-up
resistor.
SDA:
SERIAL DATA ADDRESS
The bidirectional serial data/address pin is used to
transfer all data into and out of the device. The SDA
pin is an open drain output and can be wire-ORed
with other open drain or open collector outputs.
SCL:
SERIAL CLOCK
Serial clock input.
¯¯¯:
MANUAL RESET INPUT
MR
Manual Reset input is a debounced input that can be
connected to an external source for Manual Reset.
Pulling the MR input low will generate a Reset
condition. Reset outputs are active while MR input is
low and for the reset timeout period after MR returns
to high. The input has an internal pull up resistor.
WP (CAT1021 Only):
WRITE PROTECT INPUT
When WP input is tied to V
SS
or left unconnected write
operations to the entire array are allowed. When tied
to V
CC
, the entire array is protected. This input has an
internal pull down resistor.
WDI (CAT1023 Only):
WATCHDOG TIMER INTERRUPT
Watchdog Timer Interrupt Input is used to reset the
watchdog timer. If a transition from high to low or low
to high does not occur every 1.6 seconds, the RESET
outputs will be driven active.
PIN FUNCTION
Pin
Name
NC
¯¯¯¯¯¯
RESET
V
SS
SDA
SCL
RESET
V
CC
WP
¯¯¯
MR
WDI
Function
No Connect
Active Low Reset Input/Output
Ground
Serial Data/Address
Clock Input
Active High Reset Output (CAT1021/23)
Power Supply
Write Protect (CAT1021 only)
Manual Reset Input
Watchdog Timer Interrupt (CAT1023)
OPERATING TEMPERATURE RANGE
Industrial
Extended
-40ºC to 85ºC
-40ºC to 125ºC
CAT102X FAMILY OVERVIEW
Device
Manual
Reset
Input Pin
Watchdog
Watchdog
Monitor
Pin
SDA
SDA
WDI
Write
Protection
Pin
Independent
Auxiliary
Voltage Sense
RESET:
Active High
and LOW
EEPROM
2k
CAT1021
CAT1022
2k
2k
CAT1023
CAT1024
2k
2k
CAT1025
2k
CAT1026
WDI
CAT1027
2k
For supervisory circuits with embedded 16k EEPROM, please refer to the CAT1161, CAT1162 and CAT1163
data sheets.
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
3
Doc. No. MD-3009 Rev. M
CAT1021, CAT1022, CAT1023
ABSOLUTE MAXIMUM RATINGS
(1)
Parameters
Temperature Under Bias
Storage Temperature
Voltage on any Pin with Respect to Ground
(2)
V
CC
with Respect to Ground
Package Power Dissipation Capability (T
A
= 25°C)
Lead Soldering Temperature (10 secs)
Output Short Circuit Current
(3)
Ratings
–55 to +125
–65 to +150
–2.0 to V
CC
+ 2.0
–2.0 to 7.0
1.0
300
100
Units
ºC
ºC
V
V
W
ºC
mA
D.C. OPERATING CHARACTERISTICS
V
CC
= 2.7V to 5.5V and over the recommended temperature conditions unless otherwise specified.
Symbol
I
LI
I
LO
I
CC1
I
CC2
I
SB
V
IL(4)
V
IH
(4)
Parameter
Input Leakage Current
Output Leakage Current
Power Supply Current (Write)
Power Supply Current (Read)
Standby Current
Input Low Voltage
Input High Voltage
Output Low Voltage
¯¯¯¯¯¯
(SDA, RESET)
Output High Voltage
(RESET)
Test Conditions
V
IN
= GND to V
CC
V
IN
= GND to V
CC
f
SCL
= 400kHz
V
CC
= 5.5V
f
SCL
= 400kHz
V
CC
= 5.5V
Vcc = 5.5V,
V
IN
= GND or V
CC
Min
-2
-10
Typ
Max
10
10
3
1
60
Units
µA
µA
mA
mA
µA
V
V
V
V
-0.5
0.7 x V
CC
I
OL
= 3mA
V
CC
= 2.7V
I
OH
= -0.4mA
V
CC
= 2.7V
CAT102x-45
(V
CC
= 5.0V)
CAT102x-42
(V
CC
= 5.0V)
Vcc - 0.75
4.50
4.25
3.00
2.85
2.55
1.00
15
0.3 x V
CC
V
CC
+ 0.5
0.4
V
OL
V
OH
4.75
4.50
3.15
3.00
2.70
V
V
TH
Reset Threshold
CAT102x-30
(V
CC
= 3.3V)
CAT102x-28
(V
CC
= 3.3V)
CAT102x-25
(V
CC
= 3.0V)
V
RVALID
V
RT(5)
Reset Output Valid V
CC
Voltage
Reset Threshold Hysteresis
V
mV
Notes:
(1) Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings
only, and functional operation 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.
(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 V
CC
+0.5V, which may overshoot to V
CC
+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) V
IL
min and V
IH
max are reference values only and are not tested.
(5) This parameter is tested initially and after a design or process change that affects the parameter. Not 100% tested.
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
4
Doc. No. MD-3009 Rev. M
CAT1021, CAT1022, CAT1023
CAPACITANCE
T
A
= 25ºC, f = 1.0MHz, V
CC
= 5V
Symbol
C
OUT
(1)
Test
Output Capacitance
Input Capacitance
Test Conditions
V
OUT
= 0V
V
IN
= 0V
Max
8
6
Units
pF
pF
C
IN(1)
AC CHARACTERISTICS
V
CC
= 2.7V to 5.5V and over the recommended temperature conditions, unless otherwise specified.
Memory Read & Write Cycle
(2)
Symbol
f
SCL
t
SP
t
LOW
t
HIGH
t
R
(1)
Parameter
Clock Frequency
Input Filter Spike Suppression (SDA, SCL)
Clock Low Period
Clock High Period
SDA and SCL Rise Time
SDA and SCL Fall Time
Start Condition Hold Time
Start Condition Setup Time (for a Repeated Start)
Data Input Hold Time
Data Input Setup Time
Stop Condition Setup Time
SCL Low to Data Out Valid
Data Out Hold Time
Time the Bus must be Free Before a New Transmission Can Start
Write Cycle Time (Byte or Page)
Min
Max
400
100
Units
kHz
ns
µs
µs
1.3
0.6
300
300
0.6
0.6
0
100
0.6
900
50
1.3
5
ns
ns
µs
µs
ns
ns
µs
ns
ns
µs
ms
t
F(1)
t
HD; STA
t
SU; STA
t
HD; DAT
t
SU; DAT
t
SU; STO
t
AA
t
DH
t
BUF(1)
t
WC(3)
Notes:
(1) This parameter is characterized initially and after a design or process change that affects the parameter. Not 100% tested.
(2) Test Conditions according to “AC Test Conditions” table.
(3) The write cycle time is the time from a valid stop condition of a write sequence to the end of the internal program/erase cycle. During the
write cycle, the bus interface circuits are disabled, SDA is allowed to remain high and the device does not respond to its slave address.
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
5
Doc. No. MD-3009 Rev. M
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