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Data Sheet

FULL DATA SHEET (PDF, 240kB) Download   E-Mail

Description

The DS12885, DS12887, and DS12C887 real-time clocks (RTCs) are designed to be direct replacements for the DS1285 and DS1287. The devices provide a real-time clock/calendar, one time-of-day alarm, three maskable interrupts with a common interrupt output, a programmable square wave, and 114 bytes of battery-backed static RAM (113 bytes in the DS12C887 and DS12C887A). The DS12887 integrates a quartz crystal and lithium energy source into a 24-pin encapsulated DIP package. The DS12C887 adds a century byte at address 32h. For all devices, the date at the end of the month is automatically adjusted for months with fewer than 31 days, including correction for leap years. The devices also operate in either 24-hour or 12-hour format with an AM/PM indicator. A precision temperature-compensated circuit monitors the status of VCC. If a primary power failure is detected, the device automatically switches to a backup supply. A lithium coin-cell battery can be connected to the VBAT input pin on the DS12885 to maintain time and date operation when primary power is absent. The device is accessed through a multiplexed byte-wide interface, which supports both Intel and Motorola modes.

Key Features		Applications/Uses
Drop-In Replacement for IBM AT Computer Clock/Calendar RTC Counts Seconds, Minutes, Hours, Day, Date, Month, and Year with Leap Year Compensation Through 2099 Binary or BCD Time Representation 12-Hour or 24-Hour Clock with AM and PM in 12-Hour Mode Daylight Saving Time Option Selectable Intel or Motorola Bus Timing Interfaced with Software as 128 RAM Locations 14 Bytes of Clock and Control Registers 114 Bytes of General-Purpose, Battery-Backed RAM (113 Bytes in the DS12C887 and DS12C887A) RAM Clear Function (DS12885, DS12887A, and DS12C887A) Interrupt Output with Three Independently Maskable Interrupt Flags Time-of-Day Alarm Once Per Second to Once Per Day Periodic Rates from 122µs to 500ms End-of-Clock Update Cycle Flag Programmable Square-Wave Output Automatic Power-Fail Detect and Switch Circuitry Optional 28-Pin PLCC Surface Mount Package or 32-Pin TQFP (DS12885) Optional Encapsulated DIP (EDIP) Package with Integrated Crystal and Battery (DS12887, DS12887A, DS12C887, DS12C887A) Optional Industrial Temperature Range Available Underwriters Laboratories (UL®) Recognized		Embedded Systems Network Hubs, Bridges, and Routers Security Systems Utility Meters

Diagram

Typical Operating Circuit

Application Notes

Application Note 58: Crystal Considerations with Dallas Real-Time Clocks (RTCs) - DS12885 Application Note 503: Replacing the DS1287/DS12887 Real-Time Clock in a Personal Computer - DS12C887A, DS12887, DS12887A, DS12C887 Application Note 504: Design Considerations for Dallas Semiconductor Real-Time Clocks - DS12885, DS12887 Application Note 505: Lithium Coin-Cell Batteries: Predicting an Application Lifetime - DS12885 Application Note 516: Using Multiplexed Bus Clocks with a Microcontroller - DS12885, DS12887, DS12C887 Application Note 521: Replacement for the MC146818 - DS12C887A, DS12885, DS12887, DS12887A, DS12C887 Application Note 522: Replacement for the MC146818A - DS12C887A, DS12885, DS12887, DS12887A, DS12C887 Application Note 562: Tech Brief 8: Problems and Solutions for the Year 2000 - DS12885, DS12887, DS12C887 Application Note 701: Using the DS32kHz with Dallas Real-Time Clocks - DS12885 Application Note 1145: Interface a Multiplexed-Bus Real-Time Clock to a µP With Separate Address and Data Buses - DS12C887A, DS12885, DS12887, DS12887A, DS12C887 Application Note 3778: Problems and Solutions for Adjusting to Changes in Daylight Saving Time - DS12C887, DS12C887A, DS12885, DS12887, DS12887A Application Note 3816: Selecting a Backup Source for Real-Time Clocks - DS12885

Evaluation Kits

none

Design Guides

Real-Time Clocks (PDF)

Reliability Reports

Reliability Report: DS12885.pdf DS12887.pdf Request Reliability Report for: DS12887A DS12C887A DS12C887 Underwriters Laboratories (UL®) Recognized

Software/Models

none

Ordering Information
Notes: Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales. Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day. Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt. More: SeeFull Data Sheet or Part Naming Conventions. * Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.
Devices: 1-28 of 28
DS12885	Free Sample	Buy	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
DS12885			PDIP(W);24 pin;520 mm² Outline Drawing: 21-0044 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P24-4*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS12885+			PDIP(W);24 pin;520 mm² Outline Drawing: 21-0044 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P24+4*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885N			PDIP(W);24 pin;520 mm² Outline Drawing: 21-0044 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P24-4*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
DS12885N+			PDIP(W);24 pin;520 mm² Outline Drawing: 21-0044 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P24+4*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885Q			PLCC;28 pin;158 mm² Outline Drawing: 21-0049 (PDF) Land Pattern: Not Available Use pkgcode/variation: Q28-1*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS12885Q/T&R			PLCC;28 pin;158 mm² Outline Drawing: 21-0049 (PDF) Land Pattern: Not Available Use pkgcode/variation: Q28-1*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS12885Q+			PLCC;28 pin;158 mm² Outline Drawing: 21-0049 (PDF) Land Pattern: 90-0235 (PDF) Use pkgcode/variation: Q28+2*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885Q+T&R			PLCC;28 pin;158 mm² Outline Drawing: 21-0049 (PDF) Land Pattern: 90-0235 (PDF) Use pkgcode/variation: Q28+2*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885QN			PLCC;28 pin;158 mm² Outline Drawing: 21-0049 (PDF) Land Pattern: Not Available Use pkgcode/variation: Q28-1*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
DS12885QN+			PLCC;28 pin;158 mm² Outline Drawing: 21-0049 (PDF) Land Pattern: Not Available Use pkgcode/variation: Q28+1*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885QN+T&R			PLCC;28 pin;158 mm² Outline Drawing: 21-0049 (PDF) Land Pattern: Not Available Use pkgcode/variation: Q28+1*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885SN+T&R			SOIC(W);24 pin;164 mm² Outline Drawing: 21-0042 (PDF) Land Pattern: 90-0182 (PDF) Use pkgcode/variation: W24+8*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885S			SOIC(W);24 pin;164 mm² Outline Drawing: 21-0042 (PDF) Land Pattern: 90-0182 (PDF) Use pkgcode/variation: W24-8*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS12885S+			SOIC(W);24 pin;164 mm² Outline Drawing: 21-0042 (PDF) Land Pattern: 90-0182 (PDF) Use pkgcode/variation: W24+8*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885S+T&R			SOIC(W);24 pin;164 mm² Outline Drawing: 21-0042 (PDF) Land Pattern: 90-0182 (PDF) Use pkgcode/variation: W24+8*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885SN			SOIC(W);24 pin;164 mm² Outline Drawing: 21-0042 (PDF) Land Pattern: 90-0182 (PDF) Use pkgcode/variation: W24-8*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
DS12885SN+			SOIC(W);24 pin;164 mm² Outline Drawing: 21-0042 (PDF) Land Pattern: 90-0182 (PDF) Use pkgcode/variation: W24+8*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885T			TQFP;32 pin;85 mm² Outline Drawing: 21-0292 (PDF) Land Pattern: Not Available Use pkgcode/variation: C32-3*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS12885T+			TQFP;32 pin;85 mm² Outline Drawing: 21-0292 (PDF) Land Pattern: Not Available Use pkgcode/variation: C32+3*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885TN+			TQFP;32 pin;85 mm² Outline Drawing: 21-0292 (PDF) Land Pattern: Not Available Use pkgcode/variation: C32+3*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12887	Free Sample	Buy	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
DS12887			EDIP;24 pin;545 mm² Outline Drawing: 21-0241 (PDF) Land Pattern: Not Available Use pkgcode/variation: MDP24-1*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS12887+			EDIP;24 pin;545 mm² Outline Drawing: 21-0241 (PDF) Land Pattern: Not Available Use pkgcode/variation: MDP24+1*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12887A	Free Sample	Buy	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
DS12887A			EDIP;24 pin;545 mm² Outline Drawing: 21-0241 (PDF) Land Pattern: Not Available Use pkgcode/variation: MDP24-1*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS12887A+			EDIP;24 pin;545 mm² Outline Drawing: 21-0241 (PDF) Land Pattern: Not Available Use pkgcode/variation: MDP24+1*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12C887	Free Sample	Buy	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
DS12C887			EDIP;24 pin;545 mm² Outline Drawing: 21-0241 (PDF) Land Pattern: Not Available Use pkgcode/variation: MDP24-1*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS12C887+			EDIP;24 pin;545 mm² Outline Drawing: 21-0241 (PDF) Land Pattern: Not Available Use pkgcode/variation: MDP24+1*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12C887A	Free Sample	Buy	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
DS12C887A			EDIP;24 pin;545 mm² Outline Drawing: 21-0241 (PDF) Land Pattern: Not Available Use pkgcode/variation: MDP24-1*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS12C887A+			EDIP;24 pin;545 mm² Outline Drawing: 21-0241 (PDF) Land Pattern: Not Available Use pkgcode/variation: MDP24+1*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis

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Description   Key Features   Applications/Uses   Key Specifications   Diagram

Data Sheet   Application Notes   Design Guides   Engineering Journals   Reliability Reports   Software/Models   Evaluation Kits

Price and Availability   Samples   Buy Online   Package Information   Lead-Free Information

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