DS1501/DS1511

Y2K-Compliant Watchdog Real-Time Clocks

GENERAL DESCRIPTION

The DS1501/DS1511 are full-function, year 2000-

compliant real-time clock/calendars (RTCs) with an

RTC alarm, watchdog timer, power-on reset, battery

monitors, 256 bytes NV SRAM, and a 32.768kHz

output. User access to all registers within the

DS1501/DS1511 is accomplished with a byte-wide

interface, as shown in Figure 8. The RTC registers

contain century, year, month, date, day, hours,

minutes, and seconds data in 24-hour binary-coded

decimal (BCD) format. Corrections for day of month

and leap year are made automatically.

APPLICATIONS

Remote Systems

Battery-Backed Systems

Telecom Switches

Office Equipment

Consumer Electronics

Pin Configurations and Typical Operating Circuit appear at

end of data sheet.

FEATURES

BCD-Coded Century, Year, Month, Date, Day,

Hours, Minutes, and Seconds with Automatic

Leap-Year Compensation Valid Up to the Year

2100

Programmable Watchdog Timer and RTC

Alarm

Century Register; Y2K-Compliant RTC

+3.3 (W) or +5V (Y) Operation

Precision Power-On Reset

Power-Control Circuitry Support System

Power-On from Date/Day/Time Alarm or Key

Closure/Modem-Detect Signal

256 Bytes Battery-Backed SRAM

Auxiliary Battery Input

Accuracy of DS1511 Better than ±1

Minute/Month at +25°C

Day-of-Week/Date Alarm Register

Crystal Select Bit Allow RTC to Operate with

6pF or 12.6pF Crystal (DS1501)

Battery Voltage-Level Indicator Flags

Available as Chip (DS1501) or Stand-Alone

Encapsulated DIP Module with Embedded

Battery and Crystal (DS1511)

Underwriters Laboratories (UL) Recognized

ORDERING INFORMATION

PART

VOLTAGE (V)

TEMP RANGE

PIN-PACKAGE

TOP MARK*

DS1501W+

3.3

0

°C to +70°C

28 DIP (0.600)

DS1501W

DS1501WE+

3.3

0

°C to +70°C

28 TSOP

DS1501WE

DS1501WEN+

3.3

-40

°C to +85°C

28 TSOP

DS1501WEN

DS1501WEN+T&R

3.3

-40

°C to +85°C

28 TSOP/Tape & Reel

DS1501WEN

DS1501WE+T&R

3.3

0

°C to +70°C

28 TSOP/Tape & Reel

DS1501WE

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

*A “+” anywhere on the top mark denotes a lead(Pb)-free device. An N or IND denotes an industrial temperature device.

Ordering Information continued at end of data sheet.

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REV: 010909

Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device