CAT1021LI-45-G ON Semiconductor, CAT1021LI-45-G Datasheet - Page 7

• Manufacturer Part Number: CAT1021LI-45-G
• Description: IC SUPERVISR CPU 2K EEPROM 8PDIP
• Manufacturer: ON Semiconductor
• Type: Simple Reset/Power-On Resetr

Specifications of CAT1021LI-45-G

• Number Of Voltages Monitored: 1
• Output: Open Drain or Open Collector
• Reset: Active High/Active Low
• Reset Timeout: 130 ms Minimum
• Voltage - Threshold: 4.5V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Through Hole
• Package / Case: 8-DIP (0.300", 7.62mm)
• Monitored Voltage: 3 V, 3.3 V, 5 V
• Undervoltage Threshold: 4.5 V to 4.75 V
• Manual Reset: Resettable
• Watchdog: Watchdog
• Power-up Reset Delay (typ): 200 ms
• Supply Voltage (max): 5 V
• Supply Voltage (min): 2 V
• Supply Current (typ): 3000 uA
• Maximum Power Dissipation: 1000 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

DEVICE OPERATION
Reset Controller Description
The CAT1021/22/23 precision RESET controllers
ensure correct system operation during brownout and
power up/down conditions. They are configured with
open drain RESET outputs.
During power-up, the RESET outputs remain active
until V
driving the outputs for approximately 200 ms (t
after reaching V
device will cease to drive the reset outputs. At this
point the reset outputs will be pulled up or down by
their respective pull up/down resistors.
During power-down, the RESET outputs will be active
when V
valid so long as V
designed to ignore the fast negative going V
transient pulses (glitches).
Reset output timing is shown in Figure 1.
Manual Reset Operation
The RESET
manual reset input. The input is edge triggered; that
is, the RESET
detecting a high to low transition.
When RESET
200 ms timer will begin to time the reset interval. If
external reset is shorter than 200 ms, Reset outputs
will remain active at least 200 ms.
The CAT1021/22/23 also have a separate manual
reset input. Driving the MR
pushbutton (normally open) from MR
generate a reset condition. The input has an internal
pull up resistor.
Reset remains asserted while MR
Reset Timeout period after MR
Glitches shorter than 100 ns on MR
nerate a reset pulse. No external debouncing circuits
© 2009 SCILLC. All rights reserved.
Characteristics subject to change without notice
¯¯¯¯¯¯ pin can operate as reset output and
CC
¯¯¯¯¯¯ I/O is driven to the active state, the
¯¯¯¯¯¯ input will initiate a reset timeout after
CC
reaches the V
falls below V
TH
. After the t
CC
is >1.0 V (V
¯¯¯ input low by connecting a
TH
TH
. The RESET
threshold and will continue
¯¯¯ input has gone high.
PURST
¯¯¯ is low and for the
¯¯¯¯¯¯ output will be
¯¯¯ input will not ge-
RVALID
¯¯¯ pin to GND will
timeout interval, the
). The device is
PURST
CC
)
7
are required. Manual reset operation using MR
is shown in Figure 2.
Hardware Data Protection
The CAT1021/22/23 supervisors have been designed
to solve many of the data corruption issues that have
long been associated with serial EEPROMs.
corruption occurs when incorrect data is stored in a
memory location which is assumed to hold correct data.
Whenever the device is in a Reset condition, the
embedded EEPROM is disabled for all operations,
including write operations. If the Reset output(s) are
active, in progress communications to the EEPROM
are aborted and no new communications are allowed.
In this condition an internal write cycle to the memory
can not be started, but an in progress internal non-
volatile memory write cycle can not be aborted. An
internal write cycle initiated before the Reset condition
can be successfully finished if there is enough time
(5ms) before V
In addition, the CAT1021 includes a Write Protection
Input which when tied to V
operations to the device.
Watchdog Timer
The Watchdog Timer provides an independent
protection for microcontrollers. During a system
failure, CAT1021/22/23 devices will provide a reset
signal after a time-out interval of 1.6 seconds for a
lack of activity. The CAT1023 is designed with the
Watchdog timer feature on the WDI pin. The CAT1021
and CAT1022 monitor the SDA line. If WDI or SDA
does not toggle within a 1.6 second interval, the reset
condition will be generated on the reset outputs. The
watchdog timer is cleared by any transition on a
monitored line.
As long as reset signal is asserted, the watchdog
timer will not count and will stay cleared.
CC
CAT1021, CAT1022, CAT1023
reaches the minimum value of 2V.
CC
will disable any write
Doc. No. MD-3009 Rev. P
¯¯¯ input
Data