ISL12022MIBZ datasheet(10/27 Pages) INTERSIL

部件名	ISL12022MIBZ

功能描述	Real Time Clock with Embedded Crystal, 짹5ppm Accuracy

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制造商	INTERSIL [Intersil Corporation]

网页	http://www.intersil.com/cda/home

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10 / 27 page

10

FN6668.4

December 18, 2008

The device Time Stamps the switchover from VDD to VBAT

and VBAT to VDD, and the time is stored in tSV2B and tSB2V

registers respectively. If multiple VDD power-down sequences

occur before the status is read, the earliest VDD to VBAT

power-down time is stored and the most recent VBAT to VDD

time is stored.

Temperature conversion and compensation can be enabled

in battery backup mode. Bit BTSE in the BETA register

controls this operation, as described in “BETA Register

(BETA)” on page 17.

Power Failure Detection

The ISL12022M provides a Real Time Clock Failure Bit

(RTCF) to detect total power failure. It allows users to

determine if the device has powered up after having lost all

power to the device (both VDD and VBAT).

Brownout Detection

The ISL12022M monitors the VDD level continuously and

provides warning if the VDD level drops below prescribed

levels. There are six (6) levels that can be selected for the

trip level. These values are 85% below popular VDD levels.

The LVDD bit in the Status Register will be set to “1” when

brownout is detected. Note that the I2C serial bus remains

active unless the Battery VTRIP levels are reached.

Battery Level Monitor

The ISL12022M has a built-in warning feature once the

backup battery level drops first to 85% and then to 75% of

the battery’s nominal VBAT level. When the battery voltage

drops to between 85% and 75%, the LBAT85 bit is set in the

status register. When the level drops below 75%, both

LBAT85 and LBAT75 bits are set in the status register.

There is a Battery Time Stamp Function available. Once the

VDD is low enough to enable switchover to the battery, the

RTC time/date are written into the TSV2B register. This

information can be read from the TSV2B registers to discover

the point in time of the VDD power-down. If there are multiple

power-down cycles before reading these registers, the first

values stored in these registers will be retained. These

registers will hold the original power-down value until they are

cleared by setting CLRTS = 1 to clear the registers.

The normal power switching of the ISL12022M is designed

to switch into battery backup mode only if the VDD power is

lost. This will ensure that the device can accept a wide range

of backup voltages from many types of sources while reliably

switching into backup mode.

Note that the ISL12022M is not guaranteed to operate with

VBAT < 1.8V. If the battery voltage is expected to drop lower

than this minimum, correct operation of the device, (especially

after a VDD power-down cycle) is not guaranteed.

Real Time Clock Operation

The Real Time Clock (RTC) uses an integrated 32.768kHz

quartz crystal to maintain an accurate internal representation

of second, minute, hour, day of week, date, month, and year.

The RTC also has leap-year correction. The clock also

corrects for months having fewer than 31 days and has a bit

that controls 24 hour or AM/PM format. When the

ISL12022M powers up after the loss of both VDD and VBAT,

the clock will not begin incrementing until at least one byte is

written to the clock register.

Single Event and Interrupt

The alarm mode is enabled via the MSB bit. Choosing single

event or interrupt alarm mode is selected via the IM bit. Note

that when the frequency output function is enabled, the

alarm function is disabled.

The standard alarm allows for alarms of time, date, day of

the week, month, and year. When a time alarm occurs in

single event mode, the IRQ/FOUT pin will be pulled low and

the alarm status bit (ALM) will be set to “1”.

The pulsed interrupt mode allows for repetitive or recurring

alarm functionality. Hence, once the alarm is set, the device

will continue to alarm for each occurring match of the alarm

and present time. Thus, it will alarm as often as every minute

(if only the nth second is set) or as infrequently as once a

year (if at least the nth month is set). During pulsed interrupt

mode, the IRQ/FOUT pin will be pulled low for 250ms and

the alarm status bit (ALM) will be set to “1”.

The ALM bit can be reset by the user or cleared automatically

using the auto reset mode (see ARST bit). The alarm function

can be enabled/disabled during battery backup mode using

the FOBATB bit. For more information on the alarm, please

see “ALARM Registers (10h to 15h)” on page 18.

Frequency Output Mode

The ISL12022M has the option to provide a clock output

signal using the IRQ/FOUT open drain output pin. The

frequency output mode is set by using the FO bits to select

15 possible output frequency values from 1/32Hz to 32kHz.

The frequency output can be enabled/disabled during

Battery Backup mode using the FOBATB bit.

General Purpose User SRAM

The ISL12022M provides 128 bytes of user SRAM. The

SRAM will continue to operate in battery backup mode.

However, it should be noted that the I2C bus is disabled in

battery backup mode.

I2C Serial Interface

The ISL12022M has an I2C serial bus interface that provides

access to the control and status registers and the user

SRAM. The I2C serial interface is compatible with other

industry I2C serial bus protocols using a bi-directional data

signal (SDA) and a clock signal (SCL).

ISL12022M

类似零件编号 - ISL12022MIBZ

制造商	部件名	数据表	功能描述
Intersil Corporation	ISL12022MIBZ	387Kb / 27P	Low Power RTC with Battery Backed SRAM, Integrated 짹5ppm Temperature Compensation, and Auto Daylight Saving
Intersil Corporation	ISL12022MIBZ	620Kb / 31P	Low Power RTC with Battery Backed SRAM,Integrated 짹5ppm Temperature Compensation and Auto Daylight Saving
Renesas Technology Corp	ISL12022MIBZ	1Mb / 32P	Low Power RTC with Battery Backed SRAM, Integrated 짹5ppm Temperature Compensation and Auto Daylight Saving
Renesas Technology Corp	ISL12022MIBZ	1Mb / 33P	Low Power RTC with Battery Backed SRAM, Integrated ±5ppm Temperature Compensation and Auto Daylight Saving Oct 24, 2019
Intersil Corporation	ISL12022MIBZ-T	620Kb / 31P	Low Power RTC with Battery Backed SRAM,Integrated 짹5ppm Temperature Compensation and Auto Daylight Saving

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