Low-Voltage SPI/3-Wire RTCs with
Trickle Charger
POWER-UP/POWER-DOWN CHARACTERISTICS
(T
A
= -40擄C to +85擄C) (Figures 5, 6)
PARAMETER
V
CC
Detect to Recognize Inputs
(V
CC
Rising)
V
CC
Fall Time; V
PF(MAX)
to
V
PF(MIN)
V
CC
Rise Time; V
PF(MIN)
to
V
PF(MAX)
SYMBOL
t
RST
t
F
t
R
(Note 17)
300
0
CONDITIONS
MIN
TYP
160
MAX
200
UNITS
ms
碌s
碌s
DS1390/DS1391/DS1392/DS1393
V
CC
V
PF(MAX)
V
PF(MIN)
tF
V
PF
V
PF
tR
tRPU
tRST
RST
INPUTS
RECOGNIZED
DON'T CARE
RECOGNIZED
HIGH-IMPEDANCE
OUTPUTS
VALID
VALID
Figure 5. Power-Up/Down Timing
RST
PB
DB
t
RST
Figure 6. Pushbutton Reset Timing
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7