DATASHEET
ISL12022M
Low Power RTC with Battery Backed SRAM, Integrated ±5ppm Temperature
Compensation and Auto Daylight Saving
The
ISL12022M
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 across 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.
FN6668
Rev.10.00
Oct 24, 2019
Features
• Embedded 32.768kHz quartz crystal in the package
• 20 Ld SOIC package (for DFN version, see 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 maximum battery current
• I
2
C Bus
• RoHS compliant
Related Literature
For a full list of related documents, visit our website:
•
ISL12022M
device page
Applications
• Utility meters
• POS equipment
• Printers and copiers
• Digital cameras
5
F
OUT
FREQUENCY ERROR (ppm)
1 NC
2 NC
3 NC
4 NC
SCHOTTKY DIODE
BAT54
BATTERY
3.0V
C2
0.1µF
5 NC
6 GND
7 V
BAT
8 GND
NC 20
NC 19
NC 18
NC 17
NC 16
GND 15
3.3V
C1
0.1µF
R1 R2 R3
10k 10k 10k
4
3
2
1
0
-1
-2
-3
-4
-5
-40
-20
0
20
40
TEMPERATURE (°C)
60
80
V
DD
= 3.3V
V
DD
= 5.5V
V
DD
= 2.7V
V
DD
14
IRQ/ 13
F
OUT
9 NC
12
SCL
11
10 NC
SDA
ISL12022M
IRQ/F
OUT
V
DD
SCL MCU
INTERFACE
SDA
GND
FIGURE 1. TYPICAL APPLICATION CIRCUIT
FIGURE 2.
OSCILLATOR ERROR vs TEMPERATURE
FN6668 Rev.10.00
Oct 24, 2019
Page 1 of 33
ISL12022M
Table of Contents
Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Pin Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Pin Descriptions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Ordering Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
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) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Addresses [07h to 0Fh] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Interrupt Control Register (INT). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Power Supply Control Register (PWR_VDD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Battery Voltage Trip Voltage Register (PWR_VBAT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Initial AT and DT Setting Register (ITRO). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
ALPHA Register (ALPHA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
BETA Register (BETA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
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). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
TEMP Registers (TEMP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
NPPM Registers (NPPM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
FN6668 Rev.10.00
Oct 24, 2019
Page 2 of 33
ISL12022M
XT0 Registers (XT0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
ALPHA Hot Register (ALPHAH) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
User Registers (Accessed by Using Slave Address 1010111x). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Addresses [00h to 7Fh] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
I
2
C Serial Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Protocol Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Device Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Write Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Read Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
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
Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Package Outline Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
FN6668 Rev.10.00
Oct 24, 2019
Page 3 of 33
ISL12022M
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
20 LD SOIC
TOP VIEW
NC
NC
NC
NC
NC
GND
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
NC
NC
NC
NC
NC
GND
V
DD
IRQ/F
OUT
SCL
SDA
Pin Descriptions
PIN NUMBER
1, 2, 3, 4, 5, 9,
10, 16, 17, 18,
19, 20
7
SYMBOL
NC
DESCRIPTION
No Connection. Do not connect to a signal or supply voltage.
V
BAT
Backup Supply. This input provides a backup supply voltage to the device. V
BAT
supplies power to the device in the event
that the V
DD
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
“DC Operating Characteristics RTC” 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 V
BAT
pin is activated.
11
SDA
FN6668 Rev.10.00
Oct 24, 2019
Page 4 of 33
ISL12022M
Pin Descriptions
(Continued)
PIN NUMBER
12
SYMBOL
SCL
DESCRIPTION
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 V
BAT
pin is activated to minimize power
consumption.
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/FOUT 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 V
DD
pin to ground.
Ground Pin
13
IRQ/F
OUT
14
6, 8, 15
V
DD
GND
Ordering Information
PART NUMBER
(Notes
2, 3)
ISL12022MIBZ
ISL12022MIBZ-T
NOTES:
1. See
TB347
for details about reel specifications.
2. These 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 (lead in high melt temp solder for internal connections) and exemption
5 (lead in piezoelectric elements). These RoHS compliant products are compatible with both SnPb and Pb-free soldering operations. These 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), see the
ISL12022M
device page. For more information about MSL, see
TB363.
PART
MARKING
ISL12022MIBZ
ISL12022MIBZ
V
DD
RANGE
(V)
2.7 to 5.5
2.7 to 5.5
TEMP RANGE
(°C)
-40 to +85
-40 to +85
Tape and Reel
(Units) (Note
1)
-
1k
PACKAGE
(RoHS COMPLIANT)
20 Ld SOIC
20 Ld SOIC
PKG.
DWG. #
M20.3
M20.3
FN6668 Rev.10.00
Oct 24, 2019
Page 5 of 33
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