U5021M-NFP Atmel, U5021M-NFP Datasheet - Page 3

• Manufacturer Part Number: U5021M-NFP
• Description: IC TIMER WATCHDOG DIGITAL 8-SOIC
• Manufacturer: Atmel
• Type: Watchdog Circuitr

Specifications of U5021M-NFP

• Number Of Voltages Monitored: 1
• Output: Open Drain or Open Collector
• Reset: Active High
• Reset Timeout: Adjustable/Selectable
• Voltage - Threshold: 4.2V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Pin Description
Functional
Description
Supply Voltage, Pin 6
RC Oscillator, Pin 8
4756C–AUTO–09/04
Pin
1
2
3
4
5
6
7
8
WAKE-UP
Symbol
RESET
MODE
TRIG
GND
OSC
ENA
VDD
Function
Wake-up input (pull-down resistor)
There is one digitally debounced wake-up input. During the long watchdog window, each signal slope at
the input initiates a reset pulse at pin 5.
Trigger input (pull-up resistor)
It is connected to the microprocessor’s trigger signal.
Mode input (pull-up resistor)
The processor’s mode signal initiates the switchover between the long and the short watchdog time.
Enable output (push-pull)
It is used for the control of peripheral components. It is activated after the processor triggers three times
correctly.
Reset output (open drain)
Resets the processor in the case of a trigger error or if a wake-up pulse occurs during the long watchdog
period.
Supply voltage
Ground, reference voltage
RC oscillator
The U5021M requires a stabilized supply voltage V
trical characteristics.
An external buffer capacitor of C = 10 nF may be connected between pin 6 and GND.
The clock frequency, f, can be adjusted by the components R
formula:
where t = 1.35 + 1.57 R
R
The clock frequency determines all time periods of the logic part as shown in the table
“Electrical Characteristics” under the subheading “Timing” on page 9. With an appropri-
ate component selection, the clock frequency, f, is nearly independent of the supply
voltage as shown in Figure 3 on page 4.
Frequency tolerance f
f
1
=
in k , C
1
-- -
t
1
in nF and t in µs
max
1
(C
= 10% with R
1
+ 0.01)
1
±1%, C
1
= ±5%
DD
= 5 V ±5% to comply with its elec-
1
and C
1
according to the
U5021M
3