ISL12024IRTCZ Intersil, ISL12024IRTCZ Datasheet - Page 7

• Manufacturer Part Number: ISL12024IRTCZ
• Description: IC RTC/CALENDER 64BIT 8-TDFN
• Manufacturer: Intersil
• Type: Clock/Calendar/EEPROMr

Specifications of ISL12024IRTCZ

• Memory Size: 4K (512 x 8)
• Time Format: HH:MM:SS (12/24 hr)
• Date Format: YY-MM-DD-dd
• Interface: I²C, 2-Wire Serial
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-TDFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Description
The ISL12024IRTCZ device is a real-time clock with
clock/calendar, 64-bit unique ID, two polled alarms with
integrated 512x8 EEPROM, oscillator compensation, and
battery backup switch.
The oscillator uses an external, low-cost 32.768kHz crystal.
All compensation and trim components are integrated on the
chip. This eliminates several external discrete components
and a trim capacitor, saving board area and component cost.
The real-time clock keeps track of time with separate
registers for hours, minutes and seconds. The calendar has
separate registers for date, month, year and day-of-week.
The calendar is correct through 2099, with automatic leap
year correction.
The 64-bit unique ID is a random numbers programmed,
verified and locked at the factory and it is only accessible for
reading and cannot be altered by the customer.
The Dual Alarms can be set to any clock/calendar value for a
match. For instance, every minute, every Tuesday, or 5:23
AM on March 21. The alarms can be polled in the Status
Register or can provide a hardware interrupt (IRQ/F
Pin). There is a pulse mode for the alarms allowing for
repetitive alarm functionality.
The IRQ/F
frequency output of 1Hz, 4096Hz, or 32,768Hz or inactive.
The device offers a backup power input pin. This V
allows the device to be backed up by battery or SuperCap.
The entire ISL12024IRTCZ device is fully operational from
2.7V to 5.5V and the clock/calendar portion of the
ISL12024IRTCZ device remains fully operational down to
1.8V (Standby Power Mode).
The ISL12024IRTCZ device provides 4k bits of EEPROM
with eight modes of BlockLock™ control. The BlockLock™
allows a safe, secure memory for critical user and
configuration data, while allowing a large user storage area.
Pin Descriptions
Serial Clock (SCL)
The SCL input is used to clock all data into and out of the
device. The input buffer on this pin is always active (not
gated). The pull-up resistor on this pin must use the same
voltage source as V
Serial Data (SDA)
SDA is a bidirectional pin used to transfer data into and out
of the device. It has an open drain output and may be wire
ORed with other open drain or open collector outputs. The
input buffer is always active (not gated).
This open drain output requires the use of a pull-up resistor.
The pull-up resistor on this pin must use the same voltage
source as V
OUT
DD
. The output circuitry controls the fall time of the
pin may be software selected to provide a
DD
.
7
BAT
OUT
ISL12024IRTCZ
pin
output signal with the use of a slope controlled pull-down. The
circuit is designed to comply with 400kHz I
V
This input provides a backup supply voltage to the device.
V
supply fails. This pin can be connected to a battery, a Super
Cap or tied to ground if not used.
IRQ/F
This dual function pin can be used as an interrupt or
frequency output pin. The IRQ/F
the frequency out control bits of the INT register.
• Interrupt Mode. The pin provides an interrupt signal
• Frequency Output Mode. The pin outputs a clock signal
X1, X2
The X1 and X2 pins are the input and output, respectively, of
an inverting amplifier. An external 32.768kHz quartz crystal is
used with the ISL12024IRTCZ to supply a timebase for the
real-time clock. Internal compensation circuitry provides high
accuracy over the operating temperature range from -40°C to
+85°C. This oscillator compensation network can be used to
calibrate the crystal timing accuracy over-temperature either
during manufacturing, or with an external temperature sensor
and microcontroller for active compensation. The X2 pin is
intended to drive a crystal only, and should not drive any
external circuit.
Real-Time Clock Operation
The real-time clock (RTC) uses an external 32.768kHz
quartz crystal to maintain an accurate internal representation
of the second, minute, hour, day, date, month and year. The
RTC 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 ISL12024IRTCZ
powers up after the loss of both V
not operate until at least one byte is written to the clock
register.
Reading the Real-Time Clock
The RTC is read by initiating a Read command and
specifying the address corresponding to the register of the
real-time clock. The RTC registers can then be read in a
BAT
BAT
output. This signal notifies a host processor that an alarm
has occurred and requests action. It is an open drain
active low output.
which is related to the crystal frequency. The frequency
output is user selectable and enabled via the I
an open drain output.
FIGURE 7. RECOMMENDED CRYSTAL CONNECTION
supplies power to the device in the event the V
OUT
(Interrupt Output/Frequency Output)
OUT
DD
X1
X2
and V
mode is selected via
2
C interface speed.
BAT
, the clock will
2
C bus. It is
August 8, 2008
DD
FN6749.0