DS1685/DS1687 3V/5V Real-Time Clocks
POWER-UP/DOWN TIMING—5V
(TA = +25°C)
PARAMETER
CS High to Power-Fail
Recovery at Power-Up
SYMBOL
MIN
TYP
MAX
UNITS
ns
NOTES
tPF
0
tREC
150
ms
tF
VCC Slew Rate Power-Down
VCC Slew Rate Power-Down
300
10
µs
µs
4.0 ≤ VCC ≤ 4.5V
tFB
3.0 ≤ VCC ≤ 4.0V
tR
VCC Slew Rate Power-Up
Expected Data Retention
0
µs
4.5V ≥ VCC ≥ 4.0V
tDR
10
years
9, 10
POWER-UP/DOWN TIMING—3V
(TA = +25°C)
PARAMETER
CS High to Power-Fail
Recovery at Power-Up
SYMBOL
MIN
TYP
MAX
UNITS
ns
NOTES
tPF
0
tREC
150
ms
tF
VCC Slew Rate Power-Down
300
µs
2.5 ≤ VCC ≤ 2.7V
tR
VCC Slew Rate Power-Up
Expected Data Retention
0
µs
2.7V ≥ VCC ≥ 2.5V
tDR
10
years
9, 10
WARNING: Under no circumstances are negative undershoots, of any amplitude, allowed
when device is in battery-backup mode.
CAPACITANCE
(TA = +25°C)
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
NOTES
Input Capacitance on All Inputs
Except X1 and X2
CIN
12
pF
Output Capacitance on IRQ,
COUT
12
pF
SQW and DQ pins
WAKE-UP/KICKSTART TIMING
(TA = +25°C)
PARAMETER
SYMBOL
tKSPW
MIN
TYP
MAX
UNITS
NOTES
Kickstart Input Pulse Width
2
µs
Wake-Up/Kickstart Power On
Timeout
tPOTO
2
seconds
7
30 of 39
DALLAS [ DALLAS SEMICONDUCTOR ]
