ATA6621 Ver la hoja de datos (PDF) - Atmel Corporation
Número de pieza
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ATA6621 Datasheet PDF : 27 Pages
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ATA6621
A microcontroller with an oscillator tolerance of ±15% is sufficient to supply the trigger inputs
correctly within the time period of Twd = 14.2 ms (±15%) in an application with Rwd_osc = 51 kΩ.
Table 3-2.
Rwd_osc
kΩ
10
51
91
120
Table of Watchdog Timings
Oscillator
Period
tosc/µs
2.6
Lead
Time
td/ms
10.2
Closed
Window
t1/ms
2.08
12.5
49.4
10
22.4
87.8
17.92
29
113.7
23.2
Open Window
t2/ms
2.18
10.5
18.82
24.36
Trigger Period from
microcontroller
twd/ms
2.90
Reset time
tnres/ms
0.41
14.2
1.96
25.45
3.52
32.94
4.55
3.18
Temperature Monitor at Pin TEMP
In addition to the internal temperature monitoring of the voltage regulator, an additional sensor
measures the junction temperature and provides a linearized voltage at the TEMP pin. Together
with the analog functions of the microcontroller (for example, the analog comparator and the
Analog-to-digital converter (ADC)), this enables the application to detect overload conditions
and to take corresponding measures in order to prevent damage. An external capacitor buffers
the voltage due to the input current of the ADC.
The sensor itself is built out of three diodes which are supplied by an internal BIAS current in Pre
Normal Mode and Normal Mode. The typical voltage at T = 27°C is Vtemp = 2.2V with a typical
negative temperature coefficient of VTC,TEMP = –5.05 mV/k. In silent and sleep mode the 20 µA
current source is switched off.
Figure 3-9. Temperature Monitor
VCC
TEMP
20 µA
15
4887D–AUTO–12/06
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