TC1232COE Microchip Technology, TC1232COE Datasheet - Page 9

• Manufacturer Part Number: TC1232COE
• Description: IC MPU MONITOR 4.5V 16-SOIC
• Manufacturer: Microchip Technology
• Type: Simple Reset/Power-On Resetr

Specifications of TC1232COE

• Number Of Voltages Monitored: 1
• Output: Open Drain or Open Collector
• Reset: Active High/Active Low
• Reset Timeout: 250 ms Minimum
• Voltage - Threshold: 4.37V, 4.62V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (0.300", 7.5mm Width)
• Threshold Voltage: 4.37V
• No. Of Supervisors / Monitors: 1
• Supply Voltage Range: 4V To 5.5V
• Reset Type: Active-High / Active-Low
• Supply Current: 50µA
• Delay Time: 1200ms
• Digital Ic Case Style: SOIC
• Monitored Voltage: 4.5 V to 4.75 V
• Undervoltage Threshold: 4.5 V, 4.25 V
• Output Type: Active High, Active Low, Open Drain, Push-Pull
• Manual Reset: Resettable
• Watchdog: Watchdog
• Battery Backup Switching: No Backup
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 4 V
• Supply Current (typ): 200 uA
• Maximum Operating Temperature: + 70 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: 0 C
• Power Fail Detection: Yes
• Overvoltage Threshold: 4.74 V or 4.49 V
• Power-up Reset Delay (typ): 1000 ms
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

4.3
When the ST input is not stimulated for a preset time
period, the watchdog timer function forces RST and
RST signals to the active state. The preset time period
is determined by the TD inputs to be 150 ms with TD
connected to ground, 600 ms with TD floating or
1200 ms with TD connected to V
watchdog timer starts timing-out from the set time
period as soon as RST and RST are inactive. If a high-
to-low transition occurs on the ST input pin prior to
time-out, the watchdog timer is reset and begins to
time-out again. If the watchdog timer is allowed to time-
out, the RST and RST signals are driven to the active
state for 250 ms, minimum (Figure 4-7).
The software routine that strobes ST is critical. The
code must be in a section of software that is executed
frequently enough so the time between toggles is less
than the watchdog time-out period. One common
technique controls the microprocessor I/O line from two
sections of the program. The software might set the I/O
line high while operating in the Foreground mode and
set it low while in the Background or Interrupt modes. If
both modes do not execute correctly, the watchdog
timer issues reset pulses.
t
low transitions (ST is activated by falling edges only),
which will keep the watchdog timer from forcing the
reset outputs active for a time of t
of the voltage at the TD pin, as tabulated below:
TABLE 4-1:
Figure 4-7 shows a block diagram for using the
TC1232 with a PICmicro
input.
FIGURE 4-7:
© 2005 Microchip Technology Inc.
TD
TD pin = 0V
TD pin = Open
TD pin = VCC
Condition
is the maximum elapsed time between ST high-to-
3-Terminal
(example:
MCP1700)
Regulator
Watchdog Timer
0.1
µF
+5V
WATCHDOG TIMER
PERIODS
62.5 ms
250 ms
500 ms
Min
V
TD
Watchdog Timer.
CC
TC1232
®
TOL GND
MCU and the Watchdog
1200 ms
RST
150 ms
600 ms
ST
Typ
RST
t
TD
+5V
. t
10 k
CC
TD
RESET
I/O
PICmicro
is a function
(typ.). The
1000 ms
2000 ms
MCU
250 ms
Max
®
Preliminary
Figure 4-8 shows the expected reset output pin wave-
forms depending on the period of the ST pin falling
edge and the state of the TD input pin.
FIGURE 4-8:
4.4
The TC1232 is optimized for fast response to negative-
going changes in V
amount of electrical noise on V
using relays) may require a 0.01 µF or 0.1 µF bypass
capacitor to reduce detection sensitivity. This capacitor
should be installed as close to the TC1232 as possible
to keep the capacitor lead length short.
(when t
ST
RST (when t
RST
(when t
RST
RST (when t
(when t
RST
(when t
RST
Supply Monitor Noise Sensitivity
TD
TD
TD
TD
t
ST
(min)
(min)
t
t
TD
TD
TD
TD
(max))
(max))
DD
t
t
t
t
t
TD
TD
TD
TD
TD
Strobe Input.
. Systems with an inordinate
(min))
(min))
t
t
TD
TD
(max))
(max))
DD
TC1232
(such as systems
DS21370C-page 9
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