IDT1338

REAL-TIME CLOCK WITH BATTERY BACKED NON-VOLATILE RAM

RTC

IDT™ REAL-TIME CLOCK WITH BATTERY BACKED NON-VOLATILE RAM 2

IDT1338

REV J 111009

Pin Descriptions

X1

SCL

SQW/OUT

GND

VCC

1

2

3

4

8

7

6

5

SDA

X2

IDT

1338

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

SQW/OUT

IDT

1338C

Pin

Number

Pin

Name

Pin Description/Function

8MSOP,

8SOIC

16SOIC

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 12.5 pF. An external

32.768 kHz oscillator can also drive the IDT1338. In this configuration, the X1 pin is connected to

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

2—

X2

314

Backup Supply Input for Lithium Coin Cell or Other Energy Source. Battery voltage must be held

between the minimum and maximum limits for proper operation. Diodes placed in series

4

15

GND

Connect to ground.

5

16

SDA

output and requires an external pull-up resistor (2 Kohm typical).

6

1

SCL

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

open-drain output and requires an external pull-up resistor (2 Kohm typical)

7

2

SQW/OUT

Square-Wave/Output driver. When enabled and the SQWE bit set to 1, the SQW/OUT pin

outputs one of four square-wave frequencies (1 Hz, 4 kHz, 8 kHz, 32 kHz). It is an open drain

output and requires an external pull-up resistor (10K ohm typical). Operates when the device is

83

Device power supply. When voltage is applied within specified limits, the device is fully

—

4 - 13

NC

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