DS3231SN#T&R 参数 Datasheet PDF下载

Extremely Accurate I

2

C-Integrated

RTC/TCXO/Crystal

DS3231

Data Transfer on I

2

C Serial Bus

SDA

t

BUF

t

F

t

LOW

SCL

t

HD:STA

t

SP

t

HIGH

t

HD:STA

t

R

t

HD:DAT

STOP

START

t

SU:DAT

REPEATED

START

t

SU:STA

t

SU:STO

NOTE:

TIMING IS REFERENCED TO V

IL(MAX)

AND V

IH(MIN)

.

WARNING: Negative undershoots below -0.3V while the part is in battery-backed mode may cause loss of data.

Limits at -40°C are guaranteed by design and not production tested.

All voltages are referenced to ground.

I

CCA

—SCL clocking at max frequency = 400kHz.

Current is the averaged input current, which includes the temperature conversion current.

The

RST

pin has an internal 50kΩ (nominal) pullup resistor to V

CC

.

After this period, the first clock pulse is generated.

A device must internally provide a hold time of at least 300ns for the SDA signal (referred to the V

IH(MIN)

of the SCL signal)

to bridge the undefined region of the falling edge of SCL.

Note 8:

The maximum t

HD:DAT

needs only to be met if the device does not stretch the low period (t

LOW

) of the SCL signal.

Note 9:

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 10:

C

B

—total capacitance of one bus line in pF.

Note 11:

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

0.0V

≤

V

CC

≤

V

CC(MAX)

and 2.3V

≤

V

BAT

≤

3.4V.

Note 12:

This delay applies only if the oscillator is enabled and running. If the

EOSC

bit is a 1, t

REC

is bypassed and

RST

immediate-

ly goes high. The state of

RST

does not affect the I

2

C interface, RTC, or TCXO.

Note 1:

Note 2:

Note 3:

Note 4:

Note 5:

Note 6:

Note 7:

6

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