ISL12020MIRZ-T7A Datasheet, PDF (3/34 Pages) Intersil Corporation – Low Power RTC with Battery Backed SRAM, Integrated ±5ppm Temperature Compensation and Auto Daylight Saving

ISL12020M
Pin Descriptions
PIN NUMBER SYMBOL
DESCRIPTION
1, 2, 3, 4, 5, 16,
17, 18, 19, 20
X2
Crystal Connection. The X1 and X2 pins are the input and output, respectively, of an inverting amplifier and are also
X1
connected to the internal 32.768kHz quartz crystal, which is the timebase for the real time clock. Compensation
circuitry with an internal temperature sensor provides frequency correction to ±5ppm over the operating temperature
range from -40°C to +85°C. The X1 and X2 pins are not to be connected to any other circuitry or power voltages, and
are best left floating. Do not connect in an application circuit, floating electrical connection.
6, 9,
10, 15
NC No connection. Do not connect to a signal or supply voltage.
7
V_BAT 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 Super Capacitor or tied to ground if not used. See the
Battery Monitor parameter in the “Electrical Specifications” table “DC Operating Characteristics - RTC” on page 6.
11
SDA 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 ORed 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 I²C interface speeds. It is disabled when
the backup power supply on the VBAT pin is activated. SDA is a bi-directional 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.
12
SCL 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.
13
IRQ/F_OUT 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. Multi-functional pin that can be used as interrupt or frequency output pin. The function is set via the
configuration register. The output is open drain and requires a pull-up resistor.
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 I²C bus. It is an open drain output.
14
V_DD Power supply. Chip power supply and ground pins. The device will operate with a power supply from VDD = 2.7V to
5.5VDC. A 0.1µF capacitor is recommended on the V_DD pin to ground.
8
GND Ground Pin
Thermal Pad
NC No Connection. Do not connect to a signal or supply voltage.
3
FN6667.5
December 13, 2011