Maxim > Products > Real-time clocks (RTCs) > DS12885, DS12887, DS12887A, ...

DS12885, DS12887, DS12887A, DS12C887, DS12C887A
Real-Time Clocks

Overview

Technical Documents

Ordering Info

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Status
Part Number	Status
DS12885	Active: In production, but some versions are no longer available. See Ordering Information.
DS12887	Active: In production, but some versions are no longer available. See Ordering Information.
DS12887A	Active: In production, but some versions are no longer available. See Ordering Information.
DS12C887	Active: In production, but some versions are no longer available. See Ordering Information.
DS12C887A	Active: In production, but some versions are no longer available. See Ordering Information.

Data Sheet

FULL DATA SHEET Download Rev 4 (PDF, 268kB) E-Mail

Description

FULL DATA SHEET Download Rev 4 (PDF, 268kB) E-Mail 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.

This product contains lithium-metal batteries. See applicable regulations for transport requirements for batteries in equipment.

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)
Application Note 504	Design considerations for Dallas Semiconductor real-time clocks
Application Note 505	Lithium Coin-Cell Batteries: Predicting an Application Lifetime
Application Note 516	Using Multiplexed Bus Clocks with a Microcontroller
Application Note 701	Using the DS32kHz with Dallas Real-Time Clocks
Application Note 1145	Interface a Multiplexed-Bus Real-Time Clock to a µP With Separate Address and Data Buses
Application Note 3778	Problems and Solutions for Adjusting to Changes in Daylight Saving Time
Application Note 3816	Selecting a Backup Source for Real-Time Clocks

Design Guides

Real-Time Clocks (PDF)

Reliability Reports
Reliability Report:	DS12885.pdf DS12887.pdf DS12C887.pdf
Request Reliability Report for:	DS12887A DS12C887A
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; -D = drypack; -U/+U on DS parts = cut tape. More: See Full Data Sheet or Maxim Product 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.

Filters

Part Number: Package: Any -------- TQFP PLCC SOIC PDIP MOD Temperature: Any -------- -40°C to +85°C 0°C to +70°C Tape and Reel

DS12885	Free Sample	Buy	Status	Recommended Replacement	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
DS12885N		N/A	No Longer Available	DS12885N+	PDIP(W);24 pin;520.4 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
DS12885		N/A	No Longer Available	DS12885+	PDIP(W);24 pin;520.4 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+			Active		PDIP(W);24 pin;520.4 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+			Active		PDIP(W);24 pin;520.4 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/T&R		N/A	No Longer Available	DS12885Q+	PLCC;28 pin;158 mm² Outline Drawing:21-0049 (PDF) Land Pattern: 90-0235 (PDF) Use pkgcode/variation: Q28-1*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS12885QN		N/A	No Longer Available	DS12885QN+	PLCC;28 pin;158 mm² Outline Drawing:21-0049 (PDF) Land Pattern: 90-0235 (PDF) Use pkgcode/variation: Q28-1*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
DS12885Q			Active		PLCC;28 pin;158 mm² Outline Drawing:21-0049 (PDF) Land Pattern: 90-0235 (PDF) Use pkgcode/variation: Q28-1*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS12885Q+T&R			Active		PLCC;28 pin;158 mm² Outline Drawing:21-0049 (PDF) Land Pattern: 90-0235 (PDF) Use pkgcode/variation: Q28+13*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885Q+			Active		PLCC;28 pin;158 mm² Outline Drawing:21-0049 (PDF) Land Pattern: 90-0235 (PDF) Use pkgcode/variation: Q28+13*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885QN+T&R			Active		PLCC;28 pin;158 mm² Outline Drawing:21-0049 (PDF) Land Pattern: 90-0235 (PDF) Use pkgcode/variation: Q28+13*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885QN+			Active		PLCC;28 pin;158 mm² Outline Drawing:21-0049 (PDF) Land Pattern: 90-0235 (PDF) Use pkgcode/variation: Q28+13*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885SN+T&R			Active		SOIC(W);24 pin;166.1 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0182 (PDF) Use pkgcode/variation: W24+1*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885S+T&R			Active		SOIC(W);24 pin;166.1 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0182 (PDF) Use pkgcode/variation: W24+1*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885S			Active		SOIC(W);24 pin;166.1 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0182 (PDF) Use pkgcode/variation: W24-1*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS12885S+			Active		SOIC(W);24 pin;166.1 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0182 (PDF) Use pkgcode/variation: W24+1*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885SN+			Active		SOIC(W);24 pin;166.1 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0182 (PDF) Use pkgcode/variation: W24+1*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885SN		N/A	No Longer Available	DS12885SN+	SOIC(W);24 pin;166.1 mm² Outline Drawing:21-0042 (PDF) Land Pattern: 90-0182 (PDF) Use pkgcode/variation: W24-1*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
DS12885T+			Active		TQFP;32 pin;84.6 mm² Outline Drawing:21-0292 (PDF) Land Pattern: 90-0297 (PDF) Use pkgcode/variation: C32+3*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12885T			Active		TQFP;32 pin;84.6 mm² Outline Drawing:21-0292 (PDF) Land Pattern: 90-0297 (PDF) Use pkgcode/variation: C32-3*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS12885TN+			Active		TQFP;32 pin;84.6 mm² Outline Drawing:21-0292 (PDF) Land Pattern: 90-0297 (PDF) Use pkgcode/variation: C32+3*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS12887	Free Sample	Buy	Status	Recommended Replacement	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
DS12887+			Active		EDIP;24 pin;544.6 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
DS12887		N/A	No Longer Available	DS12887+	EDIP;24 pin;544.6 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	Free Sample	Buy	Status	Recommended Replacement	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
DS12887A		N/A	No Longer Available	DS12887A+	EDIP;24 pin;544.6 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+			Active		EDIP;24 pin;544.6 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	Status	Recommended Replacement	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
DS12C887		N/A	No Longer Available	DS12C887+	EDIP;24 pin;544.6 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+			Active		EDIP;24 pin;544.6 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	Status	Recommended Replacement	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
DS12C887A+			Active		EDIP;24 pin;544.6 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		N/A	No Longer Available	DS12C887A+	EDIP;24 pin;544.6 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

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Document Ref.: 19-5213 Rev 4; 2010-05-06
This page last modified: 2010-05-06