General Description

The DS1340 is a real-time clock (RTC)/calendar that is

pin compatible and functionally equivalent to the ST

M41T00, including the software clock calibration. The

device additionally provides trickle-charge capability

an oscillator STOP flag. Block access of the register

map is identical to the ST device. Two additional regis-

ters, which are accessed individually, are required for

the trickle charger and flag. The clock/calendar pro-

vides seconds, minutes, hours, day, date, month, and

year information. A built-in power-sense circuit detects

power failures and automatically switches to the back-

up supply. Reads and writes are inhibited while the

clock continues to run. The device is programmed seri-

Applications

Portable Instruments

Point-of-Sale Equipment

Medical Equipment

Telecommunications

Features

♦ Enhanced Second Source for the ST M41T00

♦ Available in a Surface-Mount Package with an

Integrated Crystal (DS1340C)

♦ Software Clock Calibration

♦ RTC Counts Seconds, Minutes, Hours, Day, Date,

Month, and Year

♦ Automatic Power-Fail Detect and Switch Circuitry

♦ Trickle-Charge Capability

♦ Low Timekeeping Voltage Down to 1.3V

♦ Three Operating Voltage Ranges (1.8V, 3V, and 3.3V)

♦ Oscillator Stop Flag

♦ Available in 8-Pin µSOP or SO Packages

♦ Underwriters Laboratory (UL) Recognized

______________________________________________ Maxim Integrated Products

1

Ordering Information

4

CPU

5

6

8

12

SDA

SCL

GND

X2

X1

C1

CRYSTAL

FT/OUT

3

7

DS1340

Typical Operating Circuit

Rev 4; 3/06

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

PART

TEMP RANGE

PIN-PACKAGE

TOP

MARK†

DS1340Z-18

-40°C to +85°C 8 SO (0.150in)

D1340-18

DS1340Z-3

-40°C to +85°C 8 SO (0.150in)

DS1340-3

DS1340Z-33

-40°C to +85°C 8 SO (0.150in)

D1340-33

DS1340U-18

-40°C to +85°C 8 µSOP

1340A1-18

DS1340U-3

-40°C to +85°C 8 µSOP

1340A1-3

DS1340U-33

-40°C to +85°C 8 µSOP

1340A1-33

DS1340C-18

-40°C to +85°C 16 SO

1340C-18

DS1340C-3

-40°C to +85°C 16 SO

1340C-3

DS1340C-33

-40°C to +85°C 16 SO

1340C-33

DS1340Z-18+

-40°C to +85°C 8 SO (0.150in)

D1340-18

DS1340Z-3+

-40°C to +85°C 8 SO (0.150in)

DS1340-3

DS1340Z-33+

-40°C to +85°C 8 SO (0.150in)

D1340-33

DS1340U-18+

-40°C to +85°C 8 µSOP

1340A1-18

DS1340U-3+

-40°C to +85°C 8 µSOP

1340A1-3

DS1340U-33+

-40°C to +85°C 8 µSOP

1340A1-33

DS1340C-18#

-40°C to +85°C 16 SO

1340C-18

DS1340C-3#

-40°C to +85°C 16 SO

1340C-3

DS1340C-33#

-40°C to +85°C 16 SO

1340C-33

Inc., or one of its sublicensed Associated Companies, conveys

Pin Configurations appear at end of data sheet.

+ Denotes a lead-free/RoHS-compliant device.

# Denotes a RoHS-compliant device that may include lead that

is exempt under RoHS requirements. The lead finish is JESD97

category e3, and is compatible with both lead-based and lead-

free soldering processes.

† A "+" anywhere on the top mark denotes a lead-free device.

A "#" denotes a RoHS-compliant device.