ISL12020M

FN6667 Rev 6.00

Page 5 of 34

January 9, 2015

Pin Configuration

ISL12020M

(20 LD DFN)

TOP VIEW

X2

X2

X2

X2

X2

X1

X1

X1

X1

X1

NC

NC

VBAT

GND

NC

VDD

IRQ/FOUT

SCL

NC

SDA

19

18

17

20

16

15

14

13

12

11

2

3

4

1

5

6

7

8

9

10

THERMAL

PAD

Pin Descriptions

PIN NUMBER

SYMBOL

DESCRIPTION

1, 2, 3, 4, 5, 16,

17, 18, 19, 20

X2

X1

Crystal Connection. The X1 and X2 pins are the input and output, respectively, of an inverting amplifier and are also

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 across the temperature range

from 0°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.

7VBAT

Backup Supply. This input provides a backup supply voltage to the device. The 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. The SDA is a bidirectional 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. The 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.

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/FOUT 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. 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

VDD

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 VDD pin to ground.

8GND

Ground Pin

Thermal Pad

NC

No Connection. Do not connect to a signal or supply voltage.