DS1501 Datasheet, PDF (8/20 Pages) Dallas Semiconductor – Y2K-Compliant Watchdog Real-Time Clocks

DS1501/DS1511 Y2KC Watchdog Real-Time Clocks
WAKEUP/KICKSTART TIMING
(T_A = +25°C) (Figure 7)
PARAMETER
SYMBOL CONDITIONS MIN
TYP
MAX UNITS
Kickstart-Input Pulse Width
t_KSPW
2
ms
Wakeup/Kickstart Power-On Timeout
t_POTO
(Note 10)
2
s
Note: Time intervals shown above are referenced in Wakeup/Kickstart.
Figure 7. Wakeup/Kickstart Timing Diagram
CO N DIT IO N : V BAT
VPF < V BAT _VPF
VCC ^0V
CO N DIT IO N : ^VPF
VPF > V BAT V BAT
V CC ^0V
TD F/KSF
(IN TER NAL)
tP _{O T O}
tKSPW
V IH
___
KS
V IL
_ ___ ^{V IH}
PW R H I-Z
V IL
_ ___ ^{V IH}
IR Q H I-Z
V IL
INTER 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 VPF is less than VBAT and VBAUX, the device power is switched from VCC to the greater of VBAT or VBAUX when VCC drops below VPF. If VPF
is greater than VBAT and VBAUX, the device power is switched from VCC to the greater of VBAT or VBAUX when VCC drops below the greater
of VBAT or VBAUX.
Note 7: VBAT or VBAUX 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: tDR 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 VCC1 is applied will be added to the wakeup/kickstart timeout.
Note 11: Typical values are at +25°C, nominal (active) supply, unless otherwise noted.
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