ATA6621-PGQW Atmel, ATA6621-PGQW Datasheet - Page 14

• Manufacturer Part Number: ATA6621-PGQW
• Description: IC TXRX LIN BUS 5V/50MA 20QFN
• Manufacturer: Atmel
• Type: Transceiverr

Specifications of ATA6621-PGQW

• Number Of Drivers/receivers: 1/1
• Protocol: LIN
• Voltage - Supply: 5 V ~ 18 V
• Mounting Type: Surface Mount
• Package / Case: 20-QFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

3.19
3.19.1
14
Watchdog
ATA6621N
Typical Timing Sequence with R
Figure 3-8.
For programming purposes at the microcontroller it is potentially necessary to supply the VCC
output via an external supply while the VS pin of the system basis chip is disconnected. This
behavior is no problem for the system basis chip.
The watchdog anticipates a trigger signal from the microcontroller at the NTRIG (negative edge)
or the PTRIG (positive edge) input within a period time window of t
exceed a minimum time t
generated at output NRES. The timing basis of the watchdog is provided by the internal oscilla-
tor, of which the time period T
In Silent or Sleep mode, the watchdog is switched off to reduce current consumption.
Minimum time for first watchdog pulse is required after the undervoltage reset at NRES disap-
pears and is defined as lead time t
The trigger signal T
For example, with an external resistor of R
watchdog come out as follows:
t
t
t
t
t
After every reset the watchdog always starts with the lead time.
OSC
d
1
2
nres
= 3922
= 800
= 840
= 157
= 12.5 µs due to 51 k
12.5 µs = 10 ms
12.5 µs = 10.5 ms
12.5 µs = 49 ms
12.5 µs = 1.96 ms
Power Dissipation: Safe Operating Area versus V
Voltage V
wd_osc
wd
is adjustable between 2.9 ms and 33 ms via the external resistor R
40
30
20
50
45
35
25
55
10
15
0
S
5
= 51 k
trigmin
5
at Different Ambient Temperatures with R
6
osc
> 3 µs. If a triggering signal is not received, a reset signal will be
is adjustable via the external resistor R
7
d
.
8
9
10
wd_oscSC
11
V
S
12
(V)
= 51 k ±1%, the typical parameters of the
13
14
15
T
T
amb
CC
amb
16
= 125˚C
= 105˚C
Output Current and Supply
thja
17
wd
. The trigger signal must
= 35 K/W
18
wd_osc
19
(10 k to 120 k ).
4887I–AUTO–09/09
wd_osc
.