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CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

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Low Power RTC with Battery Backed SRAM,

Integrated ±5ppm Temperature Compensation and

Auto Daylight Saving

ISL12020M

The ISL12020M device is a low power real time clock

(RTC) with an embedded temperature sensor and

crystal. Device functions include oscillator compensation,

clock/calendar, power fail and low battery monitors,

brownout indicator, one-time, periodic or polled alarms,

intelligent battery backup switching, Battery Reseal™

function and 128 bytes of battery-backed user SRAM.

The device is offered in a 20 Ld DFN module that

contains the RTC and an embedded 32.768kHz quartz

crystal. The calibrated oscillator provides less than

±5ppm drift over the full -40°C to +85°C temperature

range.

The RTC tracks time with separate registers for hours,

minutes, and seconds. The calendar registers track date,

month, year and day of the week and are accurate

through 2099, with automatic leap year correction.

Daylight Savings time adjustment is done automatically,

using parameters entered by the user. Power fail and

battery monitors offer user-selectable trip levels. The

time stamp function records the time and date of

Features

• Embedded 32.768kHz Quartz Crystal in the Package

• 20 Ld DFN Package (for SOIC version, refer to the

ISL12022M)

•Calendar

• On-chip Oscillator Temperature Compensation

• 10-bit Digital Temperature Sensor Output

• 15 Selectable Frequency Outputs

• Interrupt for Alarm or 15 Selectable Frequency

Outputs

• Automatic Backup to Battery or Supercapacitor

• VDD and Battery Status Monitors

• Battery Reseal™ Function to Extend Battery Shelf

Life

• Power Status Brownout Monitor

• Time Stamp for Battery Switchover

• 128 Bytes Battery-Backed User SRAM

• RoHS Compliant

Applications*(see page 31)

• Utility Meters

•POS Equipment

• Printers and Copiers

•Digital Cameras

Typical Application Circuit

Performance Curve

X2

1

X2

2

X2

3

X2

4

X2

5

NC

6

7

GND

8

NC

9

NC

10

SDA 11

SCL 12

ISL12020M

NC 15

X1 16

X1 17

X1 18

X1 19

X1 20

3.3V

R1

10k

R2

10k

R3

10k

C1

0.1µF

BAT54

SDA

SCL

MCU

GND

INTERFACE

VDD

BATTERY

3.0V

C2

0.1µF

SCHOTTKY DIODE

IRQ/FOUT

-5

-4

-3

-2

-1

0

1

2

3

4

5

-40

-20

0

2040

6080

TEMPERATURE (°C)

OSCILLATOR ERROR vs TEMPERATURE

February 11, 2010

FN6667.4