
DS1390–DS1394
Low-Voltage SPI/3-Wire RTCs with
Trickle Charger
8
Maxim Integrated
OUTPUTS
VCC
VPF(MAX)
INPUTS
HIGH IMPEDANCE
RST
DON'T CARE
VALID
RECOGNIZED
VALID
VPF(MIN)
tRST
tRPU
tR
tF
VPF
Figure 5. Power-Up/Down Timing
tRST
PBDB
RST
Figure 6. Pushbutton Reset Timing
POWER-UP/POWER-DOWN CHARACTERISTICS
(TA = -40°C to +85°C) (Figures 5, 6)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
VCC Detect to Recognize Inputs
(VCC Rising)
tRST
(Note 17)
160
200
ms
VCC Fall Time; VPF(MAX) to
VPF(MIN)
tF
300
s
VCC Rise Time; VPF(MIN) to
VPF(MAX)
tR
0s