PCF2129AT/1,512 NXP Semiconductors, PCF2129AT/1,512 Datasheet - Page 20

• Manufacturer Part Number: PCF2129AT/1,512
• Description: IC REAL TIME CLK/CALENDAR 20SOIC
• Manufacturer: NXP Semiconductors
• Type: Clock/Calendar/Alarmr

Specifications of PCF2129AT/1,512

• Package / Case: 20-SOIC (7.5mm Width)
• Date Format: YY-MM-DD-dd
• Time Format: HH:MM:SS (12/24 hr)
• Interface: I²C, SPI
• Voltage - Supply: 1.8 V ~ 4.2 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Function: Clock, Alarm, Watchdog, Timestamp
• Supply Voltage (max): 4.2 V
• Supply Voltage (min): 1.8 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Rtc Bus Interface: I2C, SPI
• Supply Current: 800 uA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 568-4960-5; 935288599512

NXP Semiconductors
PCF2129A_2
Product data sheet
8.6 Oscillator stop detection function
The PCF2129A has an on-chip oscillator detection circuit which monitors the status of the
oscillation: whenever the oscillation stops, a reset occurs and the oscillator stop flag OSF
(in register Seconds) is set logic 1.
Fig 9.
•
•
V
(= 2.5 V)
(= 1.2 V)
th(sw)bat
Power-on:
a. The oscillator is not running, the chip is in reset (OSF is logic 1).
b. When the oscillator starts running and is stable after power-on, the chip exits from
c. The flag OSF is still logic 1 and can be cleared (OSF set logic 0) via the interface.
Power supply failure:
a. When the power supply of the chip (V
b. When the power supply returns to normal operation, the oscillator starts running
c. The flag OSF is still logic 1 and can be cleared (OSF set logic 0) via the interface.
(1) Theoretical state of the signals since there is no power.
(2) The oscillator stop flag (OSF), set logic 1, indicates that the oscillation has stopped and a reset has
V
OSF
V
V
V
BAT
reset.
(V
again, the chip exits from reset.
DD
low
SS
low
occurred since the flag was last cleared (OSF set logic 0). In this case the integrity of the clock
information is not guaranteed. The OSF flag is cleared using the interface.
Power failure event due to battery discharge: reset occurs
), typically 1.2 V, the oscillator stops running and a reset occurs.
V
All information provided in this document is subject to legal disclaimers.
BBS
V
BBS
V
BBS
Rev. 02 — 7 May 2010
battery discharge
DD
Integrated RTC, TCXO and quartz crystal
or V
internal power supply
BAT
(1)
V
) drops below a certain value
BBS
PCF2129A
© NXP B.V. 2010. All rights reserved.
V
V
V
BAT
DD
SS
(2)
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