DATASHEET

ISL12057
Low Cost and Low Power I2C RTC Real Time Clock/Calendar
Data Sheet
Low Power and Low Cost RTC with Alarm
Function and Dual IRQ Pins
The ISL12057 device is a low-power, real-time clock that is
pin compatible and functionally equivalent to Maxim DS1337
with clock/calendar and alarm function.
The oscillator uses an external, low-cost 32.768kHz crystal
with 6pF load capacitance. The real-time clock tracks time
with separate registers for hours, minutes, and seconds. The
device has calendar registers for date, month, year, and day
of the week. The calendar is accurate through 2099, with
automatic leap year correction.
September 25, 2015
FN6755.2
Features
• Pin Compatible to Maxim DS1337
• Functionally Equivalent to Maxim DS1337
• Real-Time Clock/Calendar
- Tracks Time in Hours, Minutes, and Seconds
- Day of the Week, Date, Month, and Year
• Dual Interrupts for Frequency Output and Alarm
interrupts
• Four Selectable Frequency Outputs
• Two Alarms
Pinouts
- Settable to the Second, Minute, Hour, Day of the Week,
and Date
ISL12057
(8 LD SOIC, MSOP)
TOP VIEW
• I2C Interface
- 400kHz Data Transfer Rate
X1
1
8
VDD
X2
2
7
IRQ1/FOUT
IRQ2
3
6
SCL
GND
4
5
SDA
• Small Package Options
-
8 Ld 2mmx2mm UTDFN
8 Ld MSOP
8 Ld SOIC
Pb-Free (RoHS Compliant)
Applications
• Utility Meters
ISL12057
(8 LD UTDFN)
TOP VIEW
X1
X2
2
3
GND
4 GER
NO
T
OR
PDD
8 UPV
S
1
IRQ2
• HVAC Equipment
B
LA
AI
AV
N
LO
L
R
EO 7
ED
• Audio/Video Components
• Set-Top Box/Television
IRQ1/FOUT
• Modems
6
SCL
• Network Routers, Hubs, Switches, Bridges
5
SDA
• Cellular Infrastructure Equipment
• Fixed Broadband Wireless Equipment
• Pagers/PDA
• Point Of Sale Equipment
• Test Meters/Fixtures
• Office Automation (Copiers, Fax)
• Home Appliances
• Computer Products
• Other Industrial/Medical/Automotive
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas LLC 2009, 2011, 2015. All Rights Reserved
Intersil (and design) and XDCP are trademarks owned by Intersil Corporation or one of its subsidiaries.
All other trademarks mentioned are the property of their respective owners.
ISL12057
Ordering Information
PART
NUMBER
PART
MARKING
VDD RANGE
(V)
TEMP. RANGE
(°C)
PACKAGE
(Pb-Free)
PKG.
DWG. #
ISL12057IBZ (Notes 1, 2)
12057 IBZ
1.4 to 3.6
-40 to +85
8 Ld SOIC
M8.15
ISL12057IUZ (Notes 1, 2)
12057
1.4 to 3.6
-40 to +85
8 Ld MSOP
M8.118
ISL12057IRUZ-T (Notes 3, 4)
(No longer available or supported)
057
1.4 to 3.6
-40 to +85
8 Ld UTDFN (Tape and Reel)
L8.2x2
ISL12057EVALZ
Evaluation Board
NOTES:
1. These Intersil Pb-free plastic packaged products employ special Pb-free material sets, molding compounds/die attach materials, and 100% matte
tin plate plus anneal (e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations). Intersil
Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
2. Add “-T*” suffix for tape and reel. Please refer to TB347 for details on reel specifications.
3. These Intersil Pb-free plastic packaged products employ special Pb-free material sets; molding compounds/die attach materials and NiPdAu
plate - e4 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products
are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
4. Please refer to TB347 for details on reel specifications.
Block Diagram
SDA
SDA
BUFFER
SCL
SCL
BUFFER
I2C
INTERFACE
SECONDS
RTC
CONTROL
LOGIC
MINUTES
HOURS
DAY OF WEEK
X1
X2
CRYSTAL
OSCILLATOR
RTC
DIVIDER
DATE
MONTH
VDD
POR
FREQUENCY
OUT
YEAR
ALARM2
ALARM1
CONTROL
REGISTERS
IRQ2
INTERNAL
SUPPLY
IRQ1/FOUT
2
FN6755.2
September 25, 2015
ISL12057
Pin Descriptions
PIN
NUMBER
SYMBOL
DESCRIPTION
1
X1
The X1 pin is the input of an inverting amplifier and is intended to be connected to one pin of an external 32.768kHz
quartz crystal. The required crystal load capacitance is 6pF. This pin can also be driven by an external 32.768kHz oscillator
with X2 pin floating.
2
X2
The X2 pin is the output of an inverting amplifier and is intended to be connected to one pin of an external 32.768kHz
quartz crystal. The required crystal load capacitance is 6pF.
3
IRQ2
Interrupt Output 2 is a multi-functional pin that can be used as an alarm interrupt. This pin is open drain and requires
an external pull-up resistor. This pin is at high impedance at power-up.
4
GND
Ground
5
SDA
Serial Data (SDA) is a bidirectional pin used to transfer serial data into and out of the device. It has an open drain output
and may be wire OR’ed with other open drain or open collector outputs.
6
SCL
The Serial Clock (SCL) input is used to clock all serial data into and out of the device.
7
IRQ1/FOUT
8
VDD
Interrupt Output 1/Frequency Output is a multi-functional pin that can be used as an alarm interrupt or frequency output
pin. The function is set via the configuration register. This pin is open drain and requires an external pull-up resistor. It
has a default output of 32.768kHz at power-up.
Power supply
3
FN6755.2
September 25, 2015
ISL12057
Absolute Maximum Ratings
Thermal Information
Voltage on VDD (Respect to GND) . . . . . . . . . . . . . . . . . -0.2V to 4V
Thermal Resistance (Typical) (Note 5)
Voltage on IRQ1/FOUT, IRQ2, SCL and SDA
(Respect to GND). . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.2V to 6V
Voltage on X1 and X2 Pins (Respect to GND). . . . . . . . . -0.2V to 4V
ESD Rating ((Per MIL-STD-883 Method 3014)
Human Body Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .>4kV
Machine Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .>350V
8 Lead SOIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
120
8 Lead MSOP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
169
8 Lead UTDFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
160
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C
Pb-free Reflow Profile . . . . . . . . . . . . . . . . . . . . . . . . .see link below
http://www.intersil.com/pbfree/Pb-FreeReflow.asp
JA (°C/W)
CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product reliability and
result in failures not covered by warranty.
NOTES:
5. JA is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details.
DC Operating Characteristics – RTC Temperature = -40°C to +85°C, unless otherwise stated. Crystal load capacitance = 6pF.
Boldface limits apply over the operating temperature range, -40°C to +85°C.
SYMBOL
PARAMETER
CONDITIONS
MIN
(Note 8)
TYP
(Note 7)
MAX
(Note 8)
UNITS
VDD
Full Operation Power Supply
1.8
3.6
V
VDDT
Timekeeping Power Supply
1.4
1.8
V
IDD1
Standby Supply Current
950
nA
IDD2
Timekeeping Current
IDD3
Supply Current With I2C Active at Clock
Speed of 400kHz
VDD = 3.6V
600
VDD = 3.3V
500
VDD = 1.8V
400
VDD = 1.6V
350
VDD = 3.6V
15
NOTES
6, 11
nA
650
nA
6, 11
nA
40
µA
ILI
Input Leakage Current on SCL
-100
100
nA
ILO
I/O Leakage Current on SDA
-100
100
nA
0.4
V
6
IRQ1/FOUT and IRQ2
VOL
Output Low Voltage
VDD = 1.8V, IOL = 3mA
Serial Interface Specifications Over the recommended operating conditions unless otherwise specified. Boldface limits apply over
the operating temperature range, -40°C to +85°C.
SYMBOL
PARAMETER
TEST CONDITIONS
MIN
(Note 8)
TYP
(Note 7)
MAX
(Note 8)
UNITS NOTES
SERIAL INTERFACE SPECS
VIL
SDA and SCL Input Buffer LOW
Voltage
-0.3
0.3 x VDD
V
VIH
SDA and SCL Input Buffer HIGH
Voltage
0.7 x VDD
5.5
V
Hysteresis SDA and SCL Input Buffer
Hysteresis
VPULLUP
0.04 x VDD
Maximum Pull-up voltage on
SDA during I2C communication
VOL
SDA Output Buffer LOW Voltage, VDD > 1.8V, VPULLUP = 5.0V
Sinking 3mA
Cpin
SDA and SCL Pin Capacitance
fSCL
SCL Frequency
tIN
Pulse width Suppression Time at
SDA and SCL Inputs
4
TA = +25°C, f = 1MHz, VDD = 5V,
VIN = 0V, VOUT = 0V
Any pulse narrower than the max spec
is suppressed.
0
V
VDD + 2
V
0.4
V
10
pF
400
kHz
50
ns
10
9
FN6755.2
September 25, 2015
ISL12057
Serial Interface Specifications Over the recommended operating conditions unless otherwise specified. Boldface limits apply over
the operating temperature range, -40°C to +85°C. (Continued)
MIN
(Note 8)
TYP
(Note 7)
MAX
(Note 8)
SYMBOL
PARAMETER
TEST CONDITIONS
tAA
SCL Falling Edge to SDA Output
Data Valid
SCL falling edge crossing 30% of VDD,
until SDA exits the 30% to 70% of VDD
window.
tBUF
Time the Bus Must Be Free
Before the Start of a New
Transmission
SDA crossing 70% of VDD during a
STOP condition, to SDA crossing 70%
of VDD during the following START
condition
1300
ns
tLOW
Clock LOW Time
Measured at the 30% of VDD crossing
1300
ns
tHIGH
Clock HIGH Time
Measured at the 70% of VDD crossing
600
ns
tSU:STA
START Condition Setup Time
SCL rising edge to SDA falling edge.
Both crossing 70% of VDD
600
ns
tHD:STA
START Condition Hold Time
From SDA falling edge crossing 30% of
VDD to SCL falling edge crossing 70%
of VDD
600
ns
tSU:DAT
Input Data Setup Time
From SDA exiting the 30% to 70% of
VDD window, to SCL rising edge
crossing 30% of VDD
100
ns
tHD:DAT
Input Data Hold Time
From SCL falling edge crossing 30% of
VDD to SDA entering the 30% to 70%
of VDD window
0
tSU:STO
STOP Condition Setup Time
From SCL rising edge crossing 70% of
VDD, to SDA rising edge crossing 30%
of VDD
600
ns
tHD:STO
STOP Condition Hold Time
From SDA rising edge to SCL falling
edge. Both crossing 70% of VDD
600
ns
Output Data Hold Time
From SCL falling edge crossing 30% of
VDD, until SDA enters the 30% to 70%
of VDD window
0
ns
tR
SDA and SCL Rise Time
From 30% to 70% of VDD
20 + 0.1 x Cb
300
From 70% to 30% of VDD
20 + 0.1 x Cb
10
tDH
tF
SDA and SCL Fall Time
Cb
Capacitive Loading of SDA or SCL Total on-chip and off-chip
Rpu
SDA and SCL Bus Pull-Up
Resistor Off-Chip
Maximum is determined by tR and tF
For Cb = 400pF, max is about
2k to~2.5k.
For Cb = 40pF, max is about 15kto
~20k
UNITS NOTES
900
900
ns
10
ns
ns
9
300
ns
9, 10
400
pF
9
k
9
1
NOTES:
6. IRQ1/FOUT inactive.
7. Typical values are for T = +25°C and 3.3V supply voltage.
8. Compliance to datasheet limits is assured by one or more methods: production test, characterization and/or design.
9. These are I2C specific parameters and are not production tested; however, they are used to set conditions for testing devices to validate
specification.
10. Parts will work with SDA pull-up voltage above the VPULLUP limit but the tAA and tFin the I2C parameters are not guaranteed.
11. Specified at +25°C.
5
FN6755.2
September 25, 2015
ISL12057
SDA vs SCL Timing
tHIGH
tF
SCL
tLOW
tR
tSU:DAT
tSU:STA
tHD:DAT
tHD:STA
SDA
(INPUT TIMING)
tSU:STO
tAA
tDH
tBUF
SDA
(OUTPUT TIMING)
Symbol Table
WAVEFORM
INPUTS
OUTPUTS
Must be steady
Will be steady
May change
from LOW
to HIGH
Will change
from LOW
to HIGH
May change
from HIGH
to LOW
Will change
from HIGH
to LOW
Don’t Care:
Changes Allowed
Changing:
State Not Known
N/A
Center Line is
High Impedance
EQUIVALENT AC OUTPUT LOAD CIRCUIT FOR VDD = 5V
5.0V
1533
SDA,
IRQ1/FOUT
AND
IRQ2
FOR VOL= 0.4V
AND IOL = 3mA
100pF
FIGURE 1. STANDARD OUTPUT LOAD FOR TESTING THE
DEVICE WITH VDD = 5.0V
6
FN6755.2
September 25, 2015
ISL12057
Typical Performance Curves
Temperature is +25°C unless otherwise specified
0.7
1.0
0.6
0.8
3.6
IDD1 (µA)
IDD1 (µA)
0.5
0.4
0.3
0.2
0.6
3.0
0.4
0.1
0
1.4
1.8
1.4
1.9
2.4
2.9
3.4
0.2
-40
-20
0
FIGURE 2. IDD1 vs VDD
60
80
32769.0
1.1
32768.8
32768Hz
1.0
32768.6
32768.4
0.9
0.8
FOUT (Hz)
IDD (µA)
40
FIGURE 3. IDD1 vs TEMPERATURE
1.2
8192Hz
0.7
0.6
4096Hz
32768.2
32768.0
32767.8
32767.6
0.5
32767.4
0.4
1Hz
0.3
0.2
1.4
20
TEMPERATURE (°C)
VDD (V)
1.9
2.4
2.9
32767.2
3.4
32767.0
1.4
1.9
VDD (V)
FIGURE 4. IDD vs VDD vs FOUT
Pin Description
The ISL12057 device is a low-power, real-time clock with
clock/calendar, power-fail indicator, and alarm function.
X1, X2
The ISL12057 has two flexible alarms, and each can be set to
any clock/calendar value for a match; for example, every
minute, every Tuesday, or at 5:23 a.m. on the first day of every
month. The alarm status is available by checking the Status
Register, or the device can be configured to provide a hardware
interrupt via the IRQ1/FOUT or IRQ2 pin. There is a repeat
mode for the alarm, which allows a periodic interrupt every
second or every minute.
7
2.9
3.4
FIGURE 5. FOUT VS VDD WITH A TYPICAL 32.768kHZ CRYSTAL
General Description
The oscillator uses an external, low-cost 32.768kHz crystal
with 6pF load capacitance. The real-time clock tracks time
with separate registers for hours, minutes, and seconds. The
device has calendar registers for date, month, year, and day
of the week. The calendar is accurate through 2099, with
automatic leap year correction.
2.4
VDD (V)
The X1 and X2 pins are the input and output, respectively, of
an inverting amplifier. An external 32.768kHz quartz crystal
with 6pF load capacitance is used with the ISL12057 to
supply a timebase for the real-time clock. See Figure 6.
The device can also be driven directly from a 32.768kHz
square wave source with peak-to-peak voltage from 0V to
VDD at X1 pin with X2 pin floating.
X1
X2
FIGURE 6. RECOMMENDED CRYSTAL CONNECTION
FN6755.2
September 25, 2015
ISL12057
This dual-function pin can be used as an alarm interrupt or a
frequency output pin. The IRQ1/FOUT mode is selected via
the control register (address 0Eh). The IRQ1/FOUT is an
open drain output.
of second, minute, hour, day of week, date, month, and year.
The RTC also has leap-year correction. The RTC corrects
for months having fewer than 31 days and has a bit that
controls 24-hour or AM/PM format. The clock begins
incrementing after power-up with valid oscillator condition.
This pin has a default output of 32.768kHz at power-up.
ACCURACY OF THE REAL TIME CLOCK
IRQ1/FOUT (Interrupt Output 1/Frequency Output)
• Interrupt Mode. The pin provides an interrupt signal
output. This signal notifies a host processor that an alarm
has occurred and requests action.
• Frequency Output Mode. The pin outputs a clock signal
that is related to the crystal frequency. The frequency
output is user selectable and is enabled via the I2C bus.
IRQ2 (Interrupt Output 2)
The IRQ2 pin is used as an Alarm1 interrupt and/or an
Alarm2 interrupt. The IRQ2 mode is selected via the control
register (address 0Eh). The IRQ2 is an open drain output.
The accuracy of the Real Time Clock depends on the
frequency of the quartz crystal that is used as the time base
for the RTC. Since the resonant frequency of a crystal is
temperature dependent, RTC performance also depends
upon temperature. The frequency deviation of the crystal is a
function of the turnover temperature of the crystal from the
crystal’s nominal frequency. For example, a ~20ppm
frequency deviation translates into an accuracy of ~1 minute
per month. These parameters are available from the crystal
manufacturer.
I2C Serial Interface
The pin provides an interrupt signal output. This signal
notifies a host processor that an alarm has occurred and
requests action.
The ISL12057 has an I2C serial bus interface that provides
access to the real-time clock registers, the control and status
registers, and the alarm registers. 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).
Serial Clock (SCL)
Register Descriptions
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).
The SCL pin can accept a logic high voltage up to 5.5V.
The registers are accessible following a slave byte of
“1101000x” and they read or write to addresses [00h:0Fh].
The defined addresses and default values are described in
Table 1.
This pin is high impedance at power-up.
Serial Data (SDA)
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 ORed
with other open drain or open collector outputs. The input
buffer is always active (not gated) in normal mode.
REGISTER ACCESS
An open drain output requires the use of a pull-up resistor,
and it can accept a pull-up voltage up to 5.5V. 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 I2C interface speeds.
The registers are divided into three sections:
NOTE: Parts will work with SDA pull-up voltage above the VPULLUP
limit, but the tAA and tFin the I2C parameters are not guaranteed.
There are no addresses above 0Fh.
VDD, GND
These are chip power supply and ground pins. The device
will have full operation with a power supply from 1.8V to
3.6VDC, and a timekeeping function with a power supply
from 1.4V to 1.8V.
A 0.1µF decoupling capacitor is recommended on the VDD
pin to ground.
Functional Description
Real Time Clock Operation
The contents of the registers can be modified by performing
a byte or a page write operation directly to any register
address. The address will wrap around from 0Fh to 00h.
1. Real Time Clock (7 bytes): Address 00h to 06h
2. Alarm (7 bytes): Address 07h to 0Dh
3. Control and Status (2 bytes): Address 0Eh to 0Fh
A register can be read by performing a random read at any
address at any time. This returns the contents of that register
location. Additional registers are read by performing a
sequential read. For the RTC registers, the read instruction
latches all clock registers into a buffer, so an update of the
clock does not change the time being read. A sequential
read will not result in the output of data from the memory
array. At the end of a read, the master supplies a stop
condition to end the operation and free the bus. After a read
or write instruction, the address remains at the previous
address plus one, so the user can execute a current address
read and continue reading the next register.
The Real Time Clock (RTC) uses an external 32.768kHz
quartz crystal to maintain an accurate internal representation
8
FN6755.2
September 25, 2015
ISL12057
TABLE 1. REGISTER MEMORY MAP
BIT
REG
REG
NAME
7
6
5
4
3
2
1
0
RANGE
DEFAULT
SC
0
SC22
SC21
SC20
SC13
SC12
SC11
SC10
0-59
00h
01H
MN
0
MN22
MN21
MN20
MN13
MN12
MN11
MN10
0-59
00h
02H
HR
0
MIL
AM/PM
HR20
HR13
HR12
HR11
HR10
1-12
+AM/PM
00h
ADDR SECTION
00H
RTC
HR21
0-23
03H
DW
0
0
0
0
0
DW12
DW11
DW10
1-7
01h
04H
DT
0
0
DT21
DT20
DT13
DT12
DT11
DT10
1-31
01h
05H
MO
CENTUR
0
0
MO20
MO13
MO12
MO11
MO10
0-12
+Century
01h
Y
06h
YR
YR23
YR22
YR21
YR20
YR13
YR12
YR11
YR10
0-99
00h
A1SC
A1M1
A1SC22
A1SC21
A1SC20
A1SC13
A1SC12
A1SC11
A1SC10
0-59
00h
08h
A1MN
A1M2
A1MN22
A1MN21
A1MN20
A1MN13
A1MN12
A1MN11
A1MN10
0-59
00h
09h
A1HR
A1M3
A1MIL
A1AM/PM
A1HR20
A1HR13
A1HR12
A1HR11
A1HR10
1-12
+AM/PM
00h
07h
Alarm1
A1HR21
0Ah
0Bh
Alarm2
0Ch
A1DW/
DT
A1M4
A2MN
A2M2
A2HR
A2M3
A1DW/DT
0-23
0
0
0
A1DW12
A1DW11
A1DW10
1-7
00h
A1DT21
A1DT20
A1DT13
A1DT12
A1DT11
A1DT10
1-31
00h
A2MN22
A2MN21
A2MN20
A2MN13
A2MN12
A2MN11
A2MN10
0-59
00h
A2MIL
A2AM/PM
A2HR20
A2HR13
A2HR12
A2HR11
A2HR10
1-12
+AM/PM
00h
A2HR21
0Dh
A2DW/
DT
A2M4
A2DW/DT
0-23
0
0
0
A2DW12
A2DW11
A2DW10
1-7
00h
A2DT21
A2DT20
A2DT13
A2DT12
A2DT11
A2DT10
1-31
00h
0Eh
Control
INT
EOSC
0
0
RS2
RS1
INTCN
A2IE
A1IE
N/A
18h
0Fh
Status
SR
OSF
0
0
0
0
0
A2F
A1F
N/A
80h
Real-Time Clock Registers
Addresses [00h to 06h]
RTC REGISTERS (SC, MN, HR, DW, DT, MO, YR)
These registers depict BCD representations of the time. As
such, SC (Seconds, address 00h) and MN (Minutes,
address 01h) range from 0 to 59, HR (Hour, address 02h)
can either be a 12-hour or 24-hour mode, DW (Day of the
Week, address 03h) is 1 to 7, DT (Date, address 04h) is 1 to
31, MO (Month, address 05h) is 1 to 12, and YR (Year,
address 06h) is 0 to 99.
The DW register provides a Day of the Week status and uses
three bits (DW2 to DW0) to represent the seven days of the
week. The counter advances in the cycle,
1-2-3-4-5-6-7-1-2-…
The assignment of a numerical value to a specific day of the
week is arbitrary and may be decided by the system
software designer.
10-hour bit (20–23 hours). If the MIL bit is “1”, the RTC uses
a 12-hour format and bit 5 of the HR register is the AM/PM
bit, with logic high being PM. The clock defaults to 24-hour
format time.
CENTURY INDICATOR
The century bit (bit 7 of the MO register) is toggled when the
years register overflows from 99 to 00 to indicate the change
of century.
LEAP YEARS
Leap years add the day February 29 and are defined as those
years that are divisible by 4. Years divisible by 100 are not leap
years, unless they are also divisible by 400. This means that
the year 2000 is a leap year, and the year 2100 is not. The
ISL12057 does not correct for the leap year in the year 2100.
Addresses [0Eh to 0Fh]
The Control and Status Registers consist of the Status
Register, Interrupt, and Alarm Register.
24-HOUR TIME
If the MIL bit of the HR register is “0”, the RTC uses a
24-hour format, and bit 5 of the HR register is the second
9
FN6755.2
September 25, 2015
ISL12057
Interrupt Control Register (INT) [Address 0Eh]
Status Register (SR) [Address 0Fh]
TABLE 2. INTERRUPT CONTROL REGISTER (INT)
ADDR
7
6
5
4
3
2
1
0
0Eh
EOSC
0
0
RS2
RS1
INTCN
A2IE
A1IE
Default
0
0
0
1
1
0
0
0
OSCILLATOR ENABLE BIT (EOSC)
The EOSC bit enables the crystal oscillator function when it
is set to “0”. When the EOSC bit is set to “1”, the crystal
oscillator function is disabled, and the device enters powersaving mode. The EOSC bit is set to “0” at power-up.
FREQUENCY OUT CONTROL BITS (RS2, RS1)
These bits select the output frequency at the IRQ1/FOUT
pin. INTCN must be set to “0” for frequency output at the
IRQ1/FOUT pin. See Table 3 for Frequency Selection of the
FOUT pin.
TABLE 3. FREQUENCY SELECTION OF FOUT PIN
FREQUENCY
FOUT (Hz)
RS2
RS1
32768
1
1
Free-running crystal clock
8192
1
0
Free-running crystal clock
4096
0
1
Free-running crystal clock
1
0
0
Sync at RTC write
COMMENT
INTERRUPT CONTROL BIT (INTCN) AND ALARM
INTERRUPT ENABLE BITS (A2IE, A1IE)
The INTCN bit controls the relationship between the alarm
interrupts and the IRQ1/FOUT and IRQ2 pins. The A2IE and
A1IE bits enable the alarm interrupts, A2F and A1F, to assert
the IRQ1/FOUT and IRQ2 pins. See Table 4 for Alarm
Interrupt Selection with INTCN, A2IE and A1IE bits.
TABLE 4. ALARM INTERRUPT SELECTION WITH INTCN,
A2IE AND A1IE BITS
INTCN
A2IE
A1IE
IRQ1/FOUT
IRQ2
0
0
0
FOUT
HIGH
0
0
1
FOUT
A1F
0
1
0
FOUT
A2F
0
1
1
FOUT
A1F or A2F
1
0
0
HIGH
HIGH
1
0
1
HIGH
A1F
1
1
0
A2F
HIGH
1
1
1
A2F
A1F
10
The Status Register is located in the memory map at
address 0Fh. This is a volatile register that provides status of
oscillator failure and alarm interrupts.
TABLE 5. STATUS REGISTER (SR)
ADDR
7
6
5
4
3
2
1
0
0Fh
OSF
0
0
0
0
0
A2F
A1F
Default
1
0
0
0
0
0
0
0
ALARM1 INTERRUPT BIT (A1F)
These bits announce if the Alarm1 matches the real-time
clock. If there is a match, the respective bit is set to “1”. This
bit is manually reset to “0” by the user. A write to this bit in
the SR can only set it to “0”, not to “1”.
ALARM2 INTERRUPT BIT (A2F)
These bits announce if the Alarm2 matches the real-time
clock. If there is a match, the respective bit is set to “1”. This
bit is manually reset to “0” by the user. A write to this bit in
the SR can only set it to “0”, not to “1”.
OSCILLATOR FAILURE BIT (OSF)
This bit is set to a “1” when there is no oscillation on the X1
pin. The bit is set by hardware (ISL12057 internally) and can
only be disabled by having an oscillation on X1 and manually
resetting to “0” to reset it.
Alarm1 Registers
Addresses [Address 07h to 0Ah]
The Alarm1 register bytes are set up identically to the RTC
register bytes, except that the MSB of each byte functions as
an enable bit (enable = “0”). These enable bits specify which
alarm registers (seconds, minutes, etc.) are used to make
the comparison. When all the enable bits are set to “1”,
Alarm1 triggers once per second. Note that there is no alarm
byte for month and year.
The Alarm1 function works as a comparison between the
Alarm1 registers and the RTC registers. As the RTC
advances, Alarm1 is triggered when a match occurs
between the Alarm1 registers and the RTC registers. Any
one Alarm1 register, multiple registers, or all registers can be
enabled for a match.
To clear Alarm1, the A1F status bit must be set to “0” with a
write.
TABLE 6. ALARM1 INTERRUPT WITH ENABLE BITS
SELECTION
A1DW/DT A1M1 A1M2 A1M3 A1M4
ALARM1 INTERRUPT
X
1
1
1
1
Every Second
X
0
1
1
1
Match Second
X
1
0
1
1
Match Minute
FN6755.2
September 25, 2015
ISL12057
TABLE 6. ALARM1 INTERRUPT WITH ENABLE BITS
SELECTION (Continued)
A1DW/DT A1M1 A1M2 A1M3 A1M4
ALARM1 INTERRUPT
X
(see Note)
1
1
0
1
Match Hour
0
1
1
1
0
Match Date
1
1
1
1
0
Match Day
0
0
0
1
1
Match Second and Minute
0
0
1
0
1
Match Second and Hour
0
0
0
0
0
Match Second, Minute
and Hour
.
.
.
.
.
.
.
.
.
.
.
.
0
1
0
0
0
Match Minute Hour and
Date
0
0
0
0
0
Match Second, Minute
Hour and Date
.
.
.
.
.
.
.
.
.
.
.
.
1
1
0
0
0
Match Minute, Hour, and
Day
1
0
0
0
0
Match Second, Minute,
Hour, and Day
NOTE: “X” is “Don’t care”; it can be set to 0 or 1.
Following is example of an Alarm1 Interrupt: a single alarm
will occur on Monday at 11:30 a.m. (Monday is when DW =
2). Set the Alarm1 registers as follows:
ALARM1
REGISTER 7
5
4
3
2
1
0
HEX
DESCRIPTION
1
0
0
0
0
0
0
0
80h Seconds disabled
A1MN
0
0
1
1
0
0
0
0
30h Minutes set to 30,
enabled
A1HR
0
1
0
1
0
0
0
1
51h Hours set to 11am,
enabled
0
The Alarm2 function works as a comparison between the
Alarm2 registers and the RTC registers. As the RTC
advances, Alarm2 is triggered when a match occurs
between the Alarm2 registers and the RTC registers. Any
one Alarm2 register, multiple registers, or all registers can be
enabled for a match.
To clear Alarm2, the A2F status bit must be set to “0” with a
write.
TABLE 7. ALARM2 INTERRUPT WITH ENABLE BITS
SELECTION
A2DW/DT A2M2
A2M3
A2M4
ALARM2 INTERRUPT
X
(see Note)
1
1
1
Every Minute (Second=00)
X
0
1
1
Match Minute
X
1
0
1
Match Hour
0
1
1
0
Match Date
1
1
1
0
Match Day
X
0
0
1
Match Minute and Hour
0
1
0
0
Match Hour and Date
0
0
1
0
Match Minute and Date
0
0
0
0
Match Minute, Hour, and Date
1
0
1
0
Match Minute and Day
1
1
0
0
Match Hour and Day
1
0
0
0
Match Minute, Hour, and Day
BIT
6
A1SC
A1DW/DT
Alarm2 will trigger once per minute. Note that there are no
alarm bytes for seconds, month, and year.
1
0
0
0
0
1
0
42h Day set to 1,
enabled
After these registers are set, an alarm is generated when the
RTC advances to exactly 11:30 a.m. on January 1 (after
seconds changes from 59 to 00) by setting the A1F bit in the
status register to “1”.
Alarm2 Registers
Addresses [Address 12h to 14h]
The Alarm2 register bytes are set up identically to the RTC
register bytes except that the MSB of each byte functions as
an enable bit (enable = “0”). These enable bits specify which
alarm registers (minutes, hour, and date/day) are used to
make the comparison. When all the enable bits are set to “1”,
11
NOTE: “X” is “Don’t care”; it can be set to 0 or 1.
Following is example of Alarm2 Interrupt: a single alarm will
occur on the first day of every month at 20:00 military time.
Set the Alarm2 registers as follows:
ALARM2
REGISTER 7
BIT
6
5
4
3
2
1
0
HEX
DESCRIPTION
A2MN
1
0
0
0
0
0
0
0
80h Minutes disabled
A2HR
0
0
1
0
0
0
0
0
20h Hours set to 20,
enabled
A2DW/DT
0
0
0
0
0
0
0
1
01h Date set to 1st,
enabled
After these registers are set, an alarm is generated when the
RTC advances to exactly 20:00 on Monday (after minutes
changes from 59 to 00) by setting the A2F bit in the status
register to “1”.
I2C Serial Interface
The ISL12057 supports a bi-directional, bus-oriented
protocol. The protocol defines any device that sends data
FN6755.2
September 25, 2015
ISL12057
onto the bus as a transmitter and the receiving device as the
receiver. The device controlling the transfer is the master,
and the device being controlled is the slave. The master
device always initiates data transfers and provides the clock
for both transmit and receive operations. Therefore, the
ISL12057 operates as a slave device in all applications.
All communication over the I2C interface is conducted by
sending the MSB of each byte of data first.
Protocol Conventions
Data states on the SDA line can change only during SCL
LOW periods. SDA state changes during SCL HIGH are
reserved for indicating START and STOP conditions (see
Figure 7). On power-up of the ISL12057, the SDA pin is in
the input mode.
All I2C interface operations must begin with a START
condition, which is a HIGH to LOW transition of SDA while
SCL is HIGH. The ISL12057 continuously monitors the SDA
and SCL lines for the START condition and does not
respond to any command until this condition is met (see
Figure 7). A START condition is ignored during the power-up
sequence.
All I2C interface operations must be terminated by a STOP
condition, which is a LOW to HIGH transition of SDA while
SCL is HIGH (see Figure 7). A STOP condition at the end of
a read operation or at the end of a write operation to memory
only places the device in its standby mode.
An acknowledge (ACK) is a software convention used to
indicate a successful data transfer. The transmitting device,
either master or slave, releases the SDA bus after
transmitting 8 bits. During the ninth clock cycle, the receiver
pulls the SDA line LOW to acknowledge reception of the 8
bits of data (see Figure 8).
The ISL12057 responds with an ACK after recognition of a
START condition followed by a valid Identification Byte, and
once again after successful receipt of an Address Byte. The
ISL12057 also responds with an ACK after receiving a Data
Byte of a write operation. The master must respond with an
ACK after receiving a Data Byte of a read operation.
SCL
SDA
DATA
STABLE
START
DATA
CHANGE
DATA
STABLE
STOP
FIGURE 7. VALID DATA CHANGES, START, AND STOP CONDITIONS
SCL FROM
MASTER
1
8
SDA OUTPUT FROM
TRANSMITTER
9
HIGH IMPEDANCE
HIGH IMPEDANCE
SDA OUTPUT FROM
RECEIVER
START
ACK
FIGURE 8. ACKNOWLEDGE RESPONSE FROM RECEIVER
12
FN6755.2
September 25, 2015
ISL12057
WRITE
SIGNALS FROM
THE MASTER
S
T
A
R
T
SIGNAL AT SDA
ADDRESS
BYTE
IDENTIFICATION
BYTE
1 1 0 1 0 0 0 0
SIGNALS FROM
THE ISL12057
S
T
O
P
LAST DATA
BYTE
FIRST DATA
BYTE
0 0 0 0
A
C
K
A
C
K
A
C
K
A
C
K
A
C
K
FIGURE 9. SEQUENTIAL BYTE WRITE SEQUENCE
Device Addressing
Write Operation
Following a start condition, the master must output a Slave
Address Byte. The seven MSBs are the device identifier.
These bits are “1101000”. Slave bits “1101” access the
register. Slave bits “000” specify the device select bits.
A Write operation requires a START condition, followed by a
valid Identification Byte, a valid Address Byte, a Data Byte,
and a STOP condition. After each of the three bytes, the
ISL12057 responds with an ACK. At this point, the I2C
interface enters a standby state.
The last bit of the Slave Address Byte defines a read or write
operation to be performed. When this R/W bit is a “1”, then a
read operation is selected. A “0” selects a write operation
(see Figure 10).
After loading the entire Slave Address Byte from the SDA
bus, the ISL12057 compares the device identifier and device
select bits with “1101000”. Upon a correct compare, the
device outputs an acknowledge on the SDA line.
Following the Slave Byte is a one-byte word address. The
word address is either supplied by the master device or
obtained from an internal counter. On power-up, the internal
address counter is set to address 0h, so a current address
read of the RTC array starts at address 0h. When required,
as part of a random read, the master must supply the 1 Word
Address Bytes as shown in Figure 11.
In a random read operation, the slave byte in the “dummy
write” portion must match the slave byte in the “read”
section. For a random read of the Clock/Control Registers,
the slave byte must be “1101000x” in both places.
R/W
SLAVE
ADDRESS BYTE
A1
A0
WORD ADDRESS
D1
D0
DATA BYTE
1
1
0
1
0
0
0
A7
A6
A5
A4
A3
A2
D7
D6
D5
D4
D3
D2
Read Operation
A Read operation consists of a 3- byte instruction followed
by one or more Data Bytes (see Figure 11). The master
device initiates the operation by issuing the following
sequence: a START, the Identification byte with the R/W bit
set to “0”, an Address Byte, a second START, and a second
Identification byte with the R/W bit set to “1”. After each of
the three bytes, the ISL12057 responds with an ACK. Then,
the ISL12057 transmits Data Bytes, as long as the master
device responds with an ACK during the SCL cycle following
the eighth bit of each byte. The master device terminates the
read operation (issuing a STOP condition) following the last
bit of the last Data Byte (see Figure 11).
The Data Bytes are from the memory location indicated by
an internal pointer. This pointer’s initial value is determined
by the Address Byte in the Read operation instruction. It
increments by one during transmission of each Data Byte.
After reaching the memory location 13h, the pointer “rolls
over” to 00h, and the device continues to output data for
each ACK received.
FIGURE 10. SLAVE ADDRESS, WORD ADDRESS, AND DATA
BYTES
13
FN6755.2
September 25, 2015
ISL12057
Application Section
SIGNALS
FROM THE
MASTER
S
T
A
R
T
SIGNAL AT
SDA
IDENTIFICATION
BYTE WITH
R/W = 0
S
T IDENTIFICATION
A
BYTE WITH
R
R/W = 1
T
ADDRESS
BYTE
S
T
O
P
A
C
K
1 1 0 1 0 0 0 1
1 1 0 1 0 0 0 0
A
C
K
SIGNALS FROM
THE SLAVE
A
C
K
A
C
K
A
C
K
FIRST READ
DATA BYTE
LAST READ
DATA BYTE
FIGURE 11. READ SEQUENCE
Oscillator Crystal Requirements
The ISL12057 uses a standard 32.768kHz crystal. Either
through-hole or surface-mount crystals can be used. Table 8
lists some recommended surface-mount crystals and the
parameters of each. This list is not exhaustive, and other
surface-mount devices can be used with the ISL12057 if
their specifications are very similar to the devices listed. The
crystal required parallel load capacitance is 6pF, and
equivalent series resistance needs to be less than 50k. The
crystal’s temperature range specification should match the
application. Many crystals are rated for -10°C to +60°C
(especially through-hole and tuning fork types), so an
appropriate crystal should be selected if extended
temperature range is required.
TABLE 8. SUGGESTED SURFACE MOUNT CRYSTALS
MANUFACTURER
PART NUMBER
Citizen
CM200S
MicroCrystal
MS3V
ECS
ECX-306
2. Add a ground trace around the crystal with one end
terminated at the chip ground. This will provide
termination for emitted noise in the vicinity of the RTC
device.
FIGURE 12. SUGGESTED LAYOUT FOR ISL12057 AND
CRYSTAL
In addition, it is a good idea to avoid a ground plane under
the X1 and X2 pins and the crystal, as this will affect the load
capacitance and therefore the oscillator accuracy of the
circuit. If the IRQ1/FOUT pin is used as a clock, it should be
routed away from the RTC device as well. The trace for the
VCC pins can be treated as a ground, and it should be routed
around the crystal.
Layout Considerations
The crystal input at X1 has a very high impedance, and
oscillator circuits operating at low frequencies (such as
32.768kHz) are known to pick up noise very easily if layout
precautions are not followed. Most instances of erratic clocking
or large accuracy errors can be traced to the susceptibility of
the oscillator circuit to interference from adjacent high-speed
clock or data lines. Careful layout of the RTC circuit will avoid
noise pickup and ensure accurate clocking.
Figure 12 shows a suggested layout for the ISL12057 device
using a surface-mount crystal. Two main precautions should
be followed:
1. Do not run the serial bus lines or any high-speed logic
lines in the vicinity of the crystal. These logic level lines
can induce noise in the oscillator circuit to cause
misclocking.
14
FN6755.2
September 25, 2015
ISL12057
Revision History
The revision history provided is for informational purposes only and is believed to be accurate, but not warranted. Please go to the web to make sure that
you have the latest revision.
DATE
REVISION
September 25, 2015
FN6755.2
CHANGE
Updated Ordering Information Table on page 2.
Added Revision History and About Intersil sections.
Updated POD M8.118 from rev 3 to rev 4. Changes since rev 4:
Corrected lead width dimension in side view 1 from "0.25 - 0.036" to "0.25 - 0.36"
Updated POD M8.15 from rev 2 to rev 4. Changes since rev 2:
Changed in Typical Recommended Land Pattern the following:
2.41(0.095) to 2.20(0.087)
0.76 (0.030) to 0.60(0.023)
0.200 to 5.20(0.205)
Changed Note 1 "1982" to "1994"
About Intersil
Intersil Corporation is a leading provider of innovative power management and precision analog solutions. The company's products
address some of the largest markets within the industrial and infrastructure, mobile computing and high-end consumer markets.
For the most updated datasheet, application notes, related documentation and related parts, please see the respective product
information page found at www.intersil.com.
You may report errors or suggestions for improving this datasheet by visiting www.intersil.com/ask.
Reliability reports are also available from our website at www.intersil.com/support
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9001 quality systems.
Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com
15
FN6755.2
September 25, 2015
ISL12057
Package Outline Drawing
M8.118
8 LEAD MINI SMALL OUTLINE PLASTIC PACKAGE
Rev 4, 7/11
5
3.0±0.05
A
DETAIL "X"
D
8
1.10 MAX
SIDE VIEW 2
0.09 - 0.20
4.9±0.15
3.0±0.05
5
0.95 REF
PIN# 1 ID
1
2
B
0.65 BSC
GAUGE
PLANE
TOP VIEW
0.55 ± 0.15
0.25
3°±3°
0.85±010
H
DETAIL "X"
C
SEATING PLANE
0.25 - 0.36
0.08 M C A-B D
0.10 ± 0.05
0.10 C
SIDE VIEW 1
(5.80)
NOTES:
(4.40)
(3.00)
1. Dimensions are in millimeters.
(0.65)
(0.40)
(1.40)
TYPICAL RECOMMENDED LAND PATTERN
16
2. Dimensioning and tolerancing conform to JEDEC MO-187-AA
and AMSEY14.5m-1994.
3. Plastic or metal protrusions of 0.15mm max per side are not
included.
4. Plastic interlead protrusions of 0.15mm max per side are not
included.
5. Dimensions are measured at Datum Plane "H".
6. Dimensions in ( ) are for reference only.
FN6755.2
September 25, 2015
ISL12057
Package Outline Drawing
L8.2x2
8 Lead Ultra Thin Dual Flat No-Lead COL Plastic Package (UTDFN COL)
Rev 3, 11/07
2X 1.5
2.00
A
6
PIN 1
INDEX AREA
PIN #1 INDEX AREA
6
B
6X 0.50
1
4
7X 0.4 ± 0.1
1X 0.5 ±0.1
2.00
(4X)
0.15
8
5
TOP VIEW
0.10 M C A B
4 0.25 +0.05 / -0.07
BOTTOM VIEW
( 8X 0 . 25 )
SEE DETAIL "X"
( 1X 0 .70 )
0 . 55 MAX
0.10 C
C
BASE PLANE
SEATING PLANE
0.08 C
(1.8 )
SIDE VIEW
C
( 7X 0 . 60 )
0 . 2 REF
0 . 00 MIN.
0 . 05 MAX.
( 6X 0 . 5 )
DETAIL "X"
TYPICAL RECOMMENDED LAND PATTERN
NOTES:
1. Dimensions are in millimeters.
Dimensions in ( ) for Reference Only.
2. Dimensioning and tolerancing conform to AMSE Y14.5m-1994.
3. Unless otherwise specified, tolerance : Decimal ± 0.05
4. Dimension b applies to the metallized terminal and is measured
between 0.15mm and 0.30mm from the terminal tip.
5. Tiebar shown (if present) is a non-functional feature.
6. The configuration of the pin #1 identifier is optional, but must be
located within the zone indicated. The pin #1 identifier may be
either a mold or mark feature.
17
FN6755.2
September 25, 2015
ISL12057
Package Outline Drawing
M8.15
8 LEAD NARROW BODY SMALL OUTLINE PLASTIC PACKAGE
Rev 4, 1/12
DETAIL "A"
1.27 (0.050)
0.40 (0.016)
INDEX
6.20 (0.244)
5.80 (0.228)
AREA
0.50 (0.20)
x 45°
0.25 (0.01)
4.00 (0.157)
3.80 (0.150)
1
2
8°
0°
3
0.25 (0.010)
0.19 (0.008)
SIDE VIEW “B”
TOP VIEW
2.20 (0.087)
SEATING PLANE
5.00 (0.197)
4.80 (0.189)
1.75 (0.069)
1.35 (0.053)
1
8
2
7
0.60 (0.023)
1.27 (0.050)
3
6
4
5
-C-
1.27 (0.050)
0.51(0.020)
0.33(0.013)
SIDE VIEW “A
0.25(0.010)
0.10(0.004)
5.20(0.205)
TYPICAL RECOMMENDED LAND PATTERN
NOTES:
1. Dimensioning and tolerancing per ANSI Y14.5M-1994.
2. Package length does not include mold flash, protrusions or gate burrs.
Mold flash, protrusion and gate burrs shall not exceed 0.15mm (0.006
inch) per side.
3. Package width does not include interlead flash or protrusions. Interlead
flash and protrusions shall not exceed 0.25mm (0.010 inch) per side.
4. The chamfer on the body is optional. If it is not present, a visual index
feature must be located within the crosshatched area.
5. Terminal numbers are shown for reference only.
6. The lead width as measured 0.36mm (0.014 inch) or greater above the
seating plane, shall not exceed a maximum value of 0.61mm (0.024 inch).
7. Controlling dimension: MILLIMETER. Converted inch dimensions are not
necessarily exact.
8. This outline conforms to JEDEC publication MS-012-AA ISSUE C.
18
FN6755.2
September 25, 2015