DS1501_09 Datasheet, PDF (8/22 Pages) Maxim Integrated Products – Y2K-Compliant Watchdog Real-Time Clocks

DS1501/DS1511 Y2KC Watchdog Real-Time Clocks
WAKEUP/KICKSTART TIMING
(T_A = +25°C) (Figure 7)
PARAMETER
Kickstart-Input Pulse Width
Wakeup/Kickstart Power-On Timeout
SYMBOL CONDITIONS MIN
t_KSPW
2
t_POTO
(Note 10)
2
Note: Time intervals shown above are referenced in Wakeup/Kickstart.
TYP
MAX
UNITS
μs
s
Figure 7. Wakeup/Kickstart Timing Diagram
C O N D IT IO N : V BAT
VPF < V BAT _VPF
VCC ^0V
C O N D IT IO N : ^VPF
VPF > VBAT VBAT
V CC ^0V
T D F /K S F
(IN T ER N AL)
tP _{O T O}
tK _{S P W}
V IH
___
KS
V IL
____ ^VIH
PW R HI-Z
V IL
____ ^VIH
IRQ HI-Z
V IL
INT ER VALS
1
2
3
4
5
Note 1: Limits at -40°C are not production tested and are guaranteed by design.
Note 2: RTC modules can be successfully processed through conventional wave-soldering techniques as long as temperature exposure to the
lithium energy source contained within does not exceed +85°C. Post-sold cleaning with water-washing techniques is acceptable,
provided that ultrasonic vibration is not used to prevent damage to the crystal.
Note 3: Voltage referenced to ground.
Note 4: Outputs are open.
Note 5: The IRQ, PWR, and RST outputs are open drain.
Note 6: If V_PF is less than V_BAT and V_BAUX, the device power is switched from V_CC to the greater of V_BAT or V_BAUX when V_CC drops below V_PF. If V_PF
is greater than V_BAT and V_BAUX, the device power is switched from V_CC to the greater of V_BAT or V_BAUX when V_CC drops below the greater
of V_BAT or V_BAUX.
Note 7: V_BAT or V_BAUX current. Using a 32,768Hz crystal connected to X1 and X2.
Note 8: These parameters are sampled with a 5pF load and are not 100% tested.
Note 9: t_DR is the amount of time that the internal battery can power the internal oscillator and internal registers of the DS1511.
Note 10: If the oscillator is not enabled, the startup time of the oscillator after V_CC1 is applied will be added to the wakeup/kickstart timeout.
Note 11: Typical values are at +25°C, nominal (active) supply, unless otherwise noted.
8 of 22