DS1337

5 of 13

PIN DESCRIPTION

PIN

NAME

DESCRIPTION

1

X1

2

X2

These signals are connections for a standard 32.768kHz quartz crystal. The internal

oscillator circuitry is designed for operation with a crystal having a specified load

considerations, refer to Application Note 58: Crystal Considerations with Dallas Real-

Time Clocks. An external 32.768kHz oscillator can also drive the DS1337. In this

configuration, the X1 pin is connected to the external oscillator signal and the X2 pin is

floated.

3

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 pullup resistor.

4

GND

DC power is provided to the device on these pins.

5

SDA

Serial Data Input/Output. SDA is the input/output pin for the 2-wire serial interface. The

SDA pin is open-drain output and requires an external pullup resistor.

6

SCL

Serial Clock Input. SCL is used to synchronize data movement on the serial interface.

7

SQW/

INTB

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

is an open-drain output and requires an external pullup resistor.

8

VCC

DC power is provided to the device on these pins.

Figure 1. Recommended Layout for Crystal