DATASHEET
ISL12022MA
Low Power RTC with Battery Backed SRAM, Integrated ±5ppm Temperature
Compensation and Auto Daylight Saving
The ISL12022MA 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. Backup battery current draw is less
than 1.6µA over the temperature range. The device is offered in
a 20 Ld SOIC 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 switchover from V
DD
to V
BAT
power, and
also from V
BAT
to V
DD
power.
The ISL12022MA features enhanced immunity to ESD per the
IEC61000-4-2 standard, and also provides improved resistance
to system leakage related to environmental moisture.
FN7575
Rev 5.00
September 5, 2012
Features
• Embedded 32.768kHz Quartz Crystal in the Package
• 20 Ld SOIC Package (for DFN version, refer to the
ISL12020M)
• 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
• V
DD
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
• 1.6µA Max Battery Current
• I
2
C Bus™
• RoHS Compliant
Applications
• Utility Meters
• POS Equipment
• Printers and Copiers
• Digital Cameras
Related Literature
• See
TB484
“ISL12022MA Enhanced RTC Module”
• See
AN1549
“Addressing Power Issues in Real Time Clock
Applications”
1
2
3
4
5
SCHOTTKY DIODE
BAT54
BATTERY
3.0V
C2
0.1µF
6
7
8
9
10
GND
GND
GND
NC
NC
NC
V
BAT
GND
NC
GND
GND
GND
NC
NC
NC
V
DD
IRQ/F
OUT
SCL
20
19
18
17
16
15
14
13
12
11
3.3V
C1
0.1µF
R1
10k
R2
10k
R3
10k
VDO
SCL
MCU
SDA
INTERFACE
GND
SDA
NC
ISL12022MA
IRQ/F
OUT
FIGURE 1. TYPICAL APPLICATION CIRCUIT
FN7575 Rev 5.00
September 5, 2012
Page 1 of 31
ISL12022MA
Block Diagram
SDA
SCL
SDA
BUFFER
SCL
BUFFER
I
2
C
INTERFACE
SECONDS
CONTROL
LOGIC
REGISTERS
MINUTES
HOURS
DAY OF WEEK
CRYSTAL
OSCILLATOR
V
DD
V
TRIP
+
-
V
BAT
GND
SWITCH
INTERNAL
SUPPLY
TEMPERATURE
SENSOR
FREQUENCY
CONTROL
RTC
DIVIDER
DATE
MONTH
POR
FREQUENCY
OUT
YEAR
ALARM
CONTROL
REGISTERS
USER
SRAM
IRQ/F
OUT
Pin Configuration
ISL12022MA
(20 LD SOIC)
TOP VIEW
GND
GND
GND
NC
NC
NC
V
BAT
GND
NC
NC
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
GND
GND
GND
NC
NC
NC
V
DD
IRQ/F
OUT
SCL
SDA
Pin Descriptions
PIN NUMBER
4, 5, 6, 9, 10,
15, 16, 17
7
SYMBOL
NC
V
BAT
DESCRIPTION
No Connection. Do not connect to a signal or supply voltage.
Backup Supply. This input provides a backup supply voltage to the device. VBAT supplies power to the device in the event
that the VDD supply fails. This pin can be connected to a battery, a supercapacitor or tied to ground if not used. See the
Battery Monitor parameter in the “” table on page 6. This pin should be tied to ground if not used.
Serial Data. SDA is a bi-directional pin used to transfer data into and out of the device. It has an open drain output and
may be OR’ed with other open drain or open collector outputs. The input buffer is always active (not gated) in normal
mode.
An open drain output requires the use of a pull-up resistor. The output circuitry controls the fall time of the output signal
with the use of a slope controlled pull-down. The circuit is designed for 400kHz I
2
C interface speeds. It is disabled when
the backup power supply on the VBAT pin is activated.
Serial Clock. The SCL input is used to clock all serial data into and out of the device. The input buffer on this pin is always
active (not gated). It is disabled when the backup power supply on the VBAT pin is activated to minimize power
consumption.
11
SDA
12
SCL
FN7575 Rev 5.00
September 5, 2012
Page 2 of 31
ISL12022MA
Pin Descriptions
(Continued)
PIN NUMBER
13
SYMBOL
IRQ/F
OUT
DESCRIPTION
Interrupt Output/Frequency Output (Default 32.768kHz frequency output). This dual function pin can be used as an
interrupt or frequency output pin. The IRQ/F
OUT
mode is selected via the frequency out control bits of the control/status
register. Interrupt Mode. The pin provides an interrupt signal output. This signal notifies a host processor that an alarm
has occurred and requests action. It is an open drain active low output. Frequency Output Mode. The pin outputs a clock
signal, which is related to the crystal frequency. The frequency output is user selectable and enabled via the I
2
C bus. It
is an open drain output. The output is open drain and requires a pull-up resistor.
Power Supply. Chip power supply and ground pins. The device will operate with a power supply from V
DD
= 2.7V to
5.5VDC. A 0.1µF capacitor is recommended on the VDD pin to ground.
Ground Pin.
14
1, 2, 3, 8, 18,
19, 20
V
DD
GND
Ordering Information
PART NUMBER
(Notes 2, 3)
ISL12022MAIBZ
ISL12022MAIBZ-T (Note 1)
PART
MARKING
ISL12022MAIBZ
ISL12022MAIBZ
V
DD
RANGE
(V)
2.7 to 5.5
2.7 to 5.5
TEMP RANGE
(°C)
-40 to +85
-40 to +85
PACKAGE
(RoHS Compliant)
20 Ld SOIC
20 Ld SOIC (Tape and Reel)
PKG.
DWG. #
M20.3
M20.3
1. Please refer to
TB347
for details on reel specifications.
2. These Intersil plastic packaged products employ special material sets, molding compounds and 100% matte tin plate plus anneal (e3) termination
finish. These products do contain Pb but they are RoHS compliant by exemption 7 (Pb in high melting temperature type solders, electronic ceramic
parts (e.g. piezoelectronic devices)) and exemption 5 (Pb in glass of electronic components). These Intersil RoHS compliant products are compatible
with both SnPb and Pb free soldering operations. These Intersil RoHS compliant products are MSL classified at Pb-free peak reflow temperatures
that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
3. For Moisture Sensitivity Level (MSL), please see device information page for
ISL12022MA.
For more information on MSL please see Tech Brief
TB363.
FN7575 Rev 5.00
September 5, 2012
Page 3 of 31
ISL12022MA
Table of Contents
Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Thermal Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
DC Operating Characteristics RTC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Power-Down Timing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
I
2
C Interface Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
SDA vs SCL Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Symbol Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Typical Performance Curves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
General Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Power Control Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Normal Mode (V
DD
) to Battery
Backup Mode (V
BAT
) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Battery Backup Mode (V
BAT
) to
Normal Mode (V
DD
). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Power Failure Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Brownout Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Battery Level Monitor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Real Time Clock Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Single Event and Interrupt. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Frequency Output Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
General Purpose User SRAM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
I
2
C Serial Interface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Oscillator Compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Register Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Real Time Clock Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Addresses [00h to 06h] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Control and Status Registers (CSR). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Addresses [07h to 0Fh] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Power Supply Control Register (PWR_VDD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Battery Voltage Trip Voltage Register
(PWR_VBAT). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Initial AT and DT Setting Register (ITRO). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
ALPHA Register (ALPHA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
BETA Register (BETA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Final Analog Trimming Register (FATR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Final Digital Trimming Register (FDTR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
ALARM Registers (10h to 15h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Time Stamp VDD to Battery Registers (TSV2B) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Time Stamp Battery to VDD Registers (TSB2V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
DST Control Registers (DSTCR). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
TEMP Registers (TEMP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
NPPM Registers (NPPM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
XT0 Registers (XT0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
ALPHA Hot Register (ALPHAH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
User Registers (Accessed by Using Slave Address 1010111x) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Addresses [00h to 7Fh] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
I
2
C Serial Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Protocol Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
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September 5, 2012
Page 4 of 31
ISL12022MA
Device Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Write Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Read Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Application Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Power Supply Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Battery Backup Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Layout Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Measuring Oscillator Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Temperature Compensation Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Daylight Savings Time (DST) Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Device Handling Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Package Outline Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
FN7575 Rev 5.00
September 5, 2012
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Microcontroller MCU
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