U5020M-MFPG3Y Atmel, U5020M-MFPG3Y Datasheet - Page 4

• Manufacturer Part Number: U5020M-MFPG3Y
• Description: IC TIMER WATCHDOG DIGITAL 16SOIC
• Manufacturer: Atmel
• Type: Watchdog Circuitr

Specifications of U5020M-MFPG3Y

• Number Of Voltages Monitored: 1
• Output: Open Drain or Open Collector
• Reset: Active High
• Reset Timeout: Adjustable/Selectable
• Voltage - Threshold: 3.8V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 4-1.
Figure 4-2.
4.3
4.4
4
Supply Voltage Monitoring, Pin 10
Switch-over Mode Time, Pin 12
t (µs)
U5020M
Reset out
Mode
V
DD
1000.00
Period t versus R
Power-up Reset and Mode Switchover
100.00
10.00
1.00
1
The integrated power-on reset (POR) circuitry sets the internal logic to a defined basic status
and generates a reset pulse at the reset output, pin 10, during ramp-up of the supply voltage and
in the case of voltage drops of the supply. A hysteresis in the POR threshold prevents the circuit
from oscillating. During ramp-up of the supply voltage, the reset output stays active for a speci-
fied period of time (t
4-2). Pin 10 has an open-drain output.
The switch-over mode time enables the synchronous operation of microcontroller and watchdog.
When the power-up reset time has elapsed, the watchdog has to be switched to monitoring
mode by the microcontroller by a “low” signal transmitted to the mode pin (pin 12) within the
time-out period, t
erates a reset pulse, t
synchronized with the switchover mode time, t
1
, at C
t
0
1
= 500 pF
1
. If the low signal does not occur within t
0
10
) in order to bring the microcontroller in its defined reset status (see
6
, and the time, t
R
1
(k )
t
1
C
1
1
, starts again. Microcontroller and watchdog are
= 500 pF
1
, each time a reset pulse is generated.
100
1
, (see
t
6
Figure
5.5 V
4.5 V
5.0 V
4-2) the watchdog gen-
1000
Pin 13
Pin 10
Pin 12
4755B–AUTO–11/05
Figure