DS1340

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

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

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 Laboratories (UL) Recognized

Ordering Information

4

CPU

5

6

8

12

SDA

SCL

GND

X2

X1

C1

CRYSTAL

FT/OUT

3

7

DS1340

Typical Operating Circuit

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)

D134033

DS1340U-18+

-40°C to +85°C

8 μSOP

1340 -18

DS1340U-3+

-40°C to +85°C

8 μSOP

1340 -3

DS1340U-33+

-40°C to +85°C

8 μSOP

1340 -33

DS1340C-18#

-40°C to +85°C

16 SO

DS1340C-18

DS1340C-3#

-40°C to +85°C

16 SO

DS1340C-3

DS1340C-33#

-40°C to +85°C

16 SO

DS1340C-33

Pin Configurations appear at end of data sheet.

+

Denotes a lead(Pb)-free/RoHS-compliant package.

#

Denotes a RoHS-compliant device that may include lead(Pb)

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(Pb)-free device.

A "#" denotes a RoHS-compliant device.

19-5578; Rev 8; 4/13