Extremely Accurate I2C RTC with
Integrated Crystal and SRAM
Data Transfer on I2C Serial Bus
SCL
NOTE: TIMING IS REFERENCED TO VIL(MAX) AND VIH(MIN).
SDA
STOP
START
REPEATED
START
tBUF
tHD:STA
tHD:DAT
tSU:DAT
tSU:STO
tHD:STA
tSP
tSU:STA
tHIGH
tR
tF
tLOW
Note 2: Limits at -40°C are guaranteed by design and not production tested.
Note 3: All voltages are referenced to ground.
Note 4: ICCA—SCL clocking at max frequency = 400kHz.
Note 5: Current is the averaged input current, which includes the temperature conversion current.
Note 6: The RST pin has an internal 50k
Ω (nominal) pullup resistor to VCC.
Note 7: After this period, the first clock pulse is generated.
Note 8: A device must internally provide a hold time of at least 300ns for the SDA signal (referred to the VIH(MIN) of the SCL signal)
to bridge the undefined region of the falling edge of SCL.
Note 9: The maximum tHD:DAT needs only to be met if the device does not stretch the low period (tLOW) of the SCL signal.
Note 10: A fast-mode device can be used in a standard-mode system, but the requirement tSU:DAT
≥ 250ns must then be met. This
is automatically the case if the device does not stretch the low period of the SCL signal. If such a device does stretch the
low period of the SCL signal, it must output the next data bit to the SDA line tR(MAX) + tSU:DAT = 1000 + 250 = 1250ns
before the SCL line is released.
Note 11: CB—total capacitance of one bus line in pF.
Note 12: Minimum operating frequency of the I2C interface is imposed by the timeout period.
Note 13: The parameter tOSF is the period of time the oscillator must be stopped for the OSF flag to be set over the voltage range of
0V
≤ VCC ≤ VCC(MAX) and 2.3V ≤ VBAT ≤ 3.4V.
Note 14: This delay only applies if the oscillator is enabled and running. If the EOSC bit is 1, tREC is bypassed and RST immediately
goes high.
WARNING: Negative undershoots below -0.3V while the part is in battery-backed mode may
cause loss of data.
DS3232
6
Maxim Integrated