L4979D Ver la hoja de datos (PDF) - STMicroelectronics
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L4979D Datasheet PDF : 22 Pages
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L4979D, L4979MD
Electrical specifications
Table 7. Reset (continued)
Pin Symbol
Parameter
Test condition
Min. Typ. Max. Unit
Res
R_p_u
Internal pull-up
resistance
With respect to Vo
12 25 50 k
Res
Vo_th
Reset threshold voltage
Vs = 5.6 to 31 V
Io = 1 to 150 mA
6% 8% 10%
below below below
Vo_ref Vo_ref Vo_ref
Vcr
Vrhth
Reset timing high
threshold
Vs = 13.5 V
44% 47% 50%
Vo_ref Vo_ref Vo_ref
Vcr
Vrlth
Reset timing low
threshold
Vs = 13.5 V
10% 13% 16%
Vo_ref Vo_ref Vo_ref
Vcr
Icr Charge current
Vs = 13.5 V
8
17 30 µA
Vcr
Idr Discharge current
Res
trr_2 Reset delay time(1)
Vs = 13.5 V
Vo = Vo_th - 100 mV
8
17 30 µA
100 250 700 µs
Res
trd Reset pulse delay
Vs = 13.5 V; Ctr = 1 nF 65
150 ms
1. When Vo becomes lower than 4 V, the reset reaction time decreases down to 2 µs assuring a faster reset
condition in this particular case.
Table 8. Watchdog
Pin Symbol
Parameter
Wi
Vih Input high voltage
Wi
Vil Input low voltage
Wi
Vih Input hysteresis
Wi
Ii Pull down current
Vcw Vwhth High threshold
Vcw
Vwlth Low threshold
Vcw
Icwc Charge current
Vcw
Icwd Discharge current
Vcw
Twop Watchdog period
Res
twol
Watchdog output low
time
Test condition
Min. Typ. Max. Unit
Vs = 13.5 V
3.5
V
Vs = 13.5 V
1.5 V
Vs = 13.5 V
300
mV
Vs = 13.5 V
10 20 µA
Vs = 13.5 V
2.20 2.35 2.50 V
Vs = 13.5 V
0.50 0.65 0.80 V
Vs = 13.5 V; Vcw = 0.1 V 4
7.5 14 µA
Vs = 13.5 V; Vcw = 2.5 V 1.0 2.4 4.5 µA
Vs = 13.5 V;
Ctw = 47 nF
25 50 90 ms
Vs = 13.5 V;
Ctw = 47 nF
6
10 22 ms
Table 9. Enable
Pin Symbol
Parameter
Test condition
En
Ven_l Enable input low voltage
En
Ven_h
Enable input high
voltage
En Ven_hy Enable input hysteresis
En
I_leak Pull down current
En = 5 V
Min. Typ. Max. Unit
1
V
3
V
700 1000 1100 mV
2
10 20 µA
Doc ID 10262 Rev 9
9/22
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