Rainbow Electronics DS1372 - Manual (Page 3)

DS1372
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Note 1: Limits at -40°C are guaranteed by design and not production tested.
Note 2: All voltages are referenced to ground.
Note 3: SCL clocking at maximum frequency = 400kHz.
Note 4: Specified with I 2 C bus inactive, SCL = SDA = V CC .
Note 5: Measured with a 32.768kHz crystal attached to the X1 and X2 pins.
Note 6: The I 2 C minimum operating frequency is imposed by the requirement of timeout period.
Note 7: The first clock pulse is generated after this period.
Note 8: A device must internally provide a hold time of at least 300ns for the SDA signal (referred to as the V IHMIN of the SCL sig-
nal) to bridge the undefined region of the falling edge of SCL.
Note 9: The maximum t HD:DAT must only be met if the device does not stretch the low period (t LOW ) of the SCL signal.
Note 10: A fast-mode device can be used in a standard-mode system, but the requirement t SU: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 t
R(MAX) + t SU:DAT = 1000 + 250 = 1250ns
before the SCL line is released.
Note 11: C B = Total capacitance of one bus line in pF.
Note 12: The parameter t OSF is the period of time the oscillator must be stopped for the OSF flag to be set over the voltage range of
2.4V ≤ V
CC
≤ V
CC(MAX) .
Note 13: The DS1372 can detect any single SCL clock held low longer than T _TIMEOUT (MIN). The I 2 C interface is in reset state and
can receive a new START condition when SCL is held low for at least T
_TIMEOUT
(MAX). Once the part detects this condi-
tion the SDA output is released. The oscillator must be running for this function to work.
ELECTRICAL CHARACTERISTICS (continued)
(V CC = 2.4V to 5.5V, T A = -40°C to +85°C, unless otherwise noted.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Fast mode 100
Data Setup Time (Note 10) t SU:DAT
Standard mode 250
ns
Fast mode
20 +
0.1C B
300
Rise Time of SDA and SCL
Signals (Note 11)
t R
Standard mode
20 +
0.1C B
1000
ns
Fast mode
20 +
0.1C
B
300
Fall Time of SDA and SCL Signals
(Note 11)
t F
Standard mode
20 +
0.1C B
300
ns
Fast mode 0.6
Setup Time for STOP Condition t SU:STO
Standard mode 4.0
μs
Capacitive Load for Each Bus
Line (Note 11)
C B 400 pF
I/O Capacitance C I/O 10 pF
SCL Spike Suppresion TSP 30 ns
Oscillator Stop Flag (OSF) Delay
(Note 12)
t
OSF
100 ms
Timeout Interval (Note 13) T _TIMEOUT 25 35 ms
CRYSTAL SPECIFICATIONS
PARAMETER SYMBOL MIN TYP MAX UNITS
Nominal Frequency f O 32.768 kHz
Capacitive Load C L 12.5 pF
Equivalent Series Resistance ESR 50 k

I
2
C, 32-Bit, Binary Counter Clock with 64-Bit ID