IDT1337

REA LTIME CLOCK WITH SERIAL INTERFACE

RTC

2

IDT1337

REV J 111009

Pin Descriptions

X1

INTA

SCL

SQW/INTB

GND

VCC

1

2

3

4

8

7

6

5

SDA

X2

IDT1337

16

1

15

2

14

3

13

4

5

6

7

8

9

10

12

11

SCL

VCC

NC

NC

NC

NC

NC

NC

NC

NC

NC

NC

SDA

GND

INTA

SQW/INTB

IDT1337C

Pin

Number

Pin

Name

Pin Description/Function

MSOP

SOIC

1

—

X1

Connections for standard 32.768 kHz quartz crystal. The internal oscillator circuitry is

designed for operation with a crystal having a specified load capacitance (CL) of 7 pF. An

external 32.768 kHz oscillator can also drive the IDT1337. In this configuration, the X1 pin

is connected to the external oscillator signal and the X2 pin is left floating.

2—

X2

314

INTA

Interrupt output. When enabled, INTA is asserted low when the time/day/date matches the

values set in the alarm registers. This pin is an open-drain output and requires an external

pull-up resistor (10 k

Ω typical).

4

15

GND

Connect to ground. DC power is provided to the device on these pins.

5

16

SDA

is an open-drain output and requires an external pull-up resistor (2 k

Ω typical).

6

1

SCL

Serial clock input. SCL is used to synchronize data movement on the serial interface. The

SCL pin is an open-drain output and requires an external pull-up resistor (2 k

Ω typical).

7

2

SQW/INTB

Square-Wave/Interrupt output. Programmable square-wave or interrupt output signal. The

SQW/INT pin is an open-drain output and requires an external pull-up resistor (10 k

Ω

typical). This pin can also function as an additional interrupt pin under certain conditions

(see page 6 for details).

8

3

VCC

Primary power supply. DC power is applied to this pin.

—

4 - 13

NC

No connect. These pins are unused and must be connected to ground.