TLE4291
Watchdog Function
9.2
Electrical Characteristics Watchdog Function
Electrical Characteristics Watchdog Function
VI = 13.5V, Tj = -40 °C to +150 °C,
all voltages with respect to ground, direction of currents as shown in Figure 8 (unless otherwise specified).
Pos. Parameter
Symbol Limit Values
Unit Conditions
Min. Typ. Max.
Watchdog Timing
9.2.1 Delay Capacitor
Charge Current
ID
–
6.5
–
μA
VD = 0.6 V
9.2.2
Delay capacitor
watchdog discharge current
IDW,disch –
1.4
–
μA
VD = 0.6 V
9.2.3 Upper watchdog timing
threshold
VDW,hi
–
0.9
–
V
–
9.2.4 Lower watchdog timing
threshold
VDW,lo
–
0.35 –
V
–
9.2.5 Watchdog Trigger Time
tWI,tr,100nF 24
40
58
ms Calculated value;
CD = 100 nF 1)
9.2.6 Watchdog Output Low Time tWD,lo,100nF 6
8
12
ms Calculated value;
CD = 100 nF 1);
VQ > VRT,lo
9.2.7 Watchdog Period
tWD,p,100nF 30
48
70
ms Calculated value;
tWI,tr,100nF + tWD,lo,100nF;
CD = 100 nF 1)
Watchdog Output WO
9.2.8
9.2.9
9.2.10
Watchdog Output
Low Voltage
Watchdog Output
Maximum Sink Current
Watchdog Output
Internal Pull-up Resistor
VWO,low
–
0.1
0.4
V
IWO = 1 mA;
VWI = 0 V
IWO,max 1.5
13
30
mA VWO = 0.8 V;
VWI = 0 V
RWO
20
30
40
kΩ –
Watchdog Input WI
9.2.11 Watchdog Input
Low Signal Valid
VWI,lo
–
–
9.2.12 Watchdog Input
High Signal Valid
VWI,hi
2.6
–
9.2.13 Watchdog Input
tWI,hi
0.5 –
High Signal Pulse Length
9.2.14 Watchdog Input
tWI,lo
2
–
Low Signal Pulse Length
(Slewrate ≥ 1 V/μs)
9.2.15 Watchdog Input
tWI,lo
0.5 –
Low Signal Pulse Length
(Slewrate ≥ 5 V/μs)
1) For programming a different watchdog timing, see Chapter 9.1.
2) For details on the test pulse applied, see Figure 9.
0.8
V
2)
–
V
2)
–
μs
VWI ≥ VWI,hi 2)
–
μs
VWI ≤ VWI,lo 2);
dVWI/dt ≥ 1 V/μs
–
μs
VWI ≤ VWI,lo 2);
dVWI/dt ≥ 5 V/μs
VWI,hi ≥ 4 V
Data Sheet
24
Rev. 1.1, 2012-12-03