BQ3287MT-I - Texas Instruments

Features

➤Direct clock/calendar replace-

ment for IBM®AT-compatible

computers and other applications

➤Functionally compatible with the

DS1287/DS1287A and MC146818A

➤114 bytes of general nonvolatile

storage

➤Integral lithium cell and crystal

➤160 ns cycle time allows fast bus

operation

➤Selectable Intel or Motorola bus

timing

➤14 bytes for clock/calendar and

control

➤BCD or binary format for clock

and calendar data

➤Time of day in seconds, minutes,

and hours

-12- or 24-hour format

-Optional daylight saving

adjustment

➤Calendar in day of the week, day

of the month, months, and years

with automatic leap-year adjust-

ment

➤Programmable square wave out-

put

➤Three individually maskable in-

terrupt event flags:

-Periodic rates from 122µsto

500 ms

-Time-of-day alarm once per

second to once per day

-End-of-clock update cycle

➤Better than one minute per

month clock accuracy

General Description

The CMOS bq3287/bq3287A is a

low-power microprocessor periph-

eral providing a time-of-day clock

and 100-year calendar with alarm

features and battery operation.

Other features include three

maskable interrupt sources, square-

wave output, and 114 bytes of gen-

eral nonvolatile storage. The

bq3287A version is identical to the

bq3287, with the addition of the RAM

clear input.

The bq3287 is a fully compatible

real-time clock for IBM AT-

compatible computers and other ap-

plications. The bq3287 write-

protects the clock, calendar, and

storage registers during power fail-

ure. The integral backup energy

source then maintains data and op-

erates the clock and calendar.

As shipped from Benchmarq, the

real time clock is turned off to maxi-

mize battery capacity for in-system

operation.

The bq3287 is functionally equiva-

lent to the bq3285, except that the

battery (16, 20) and crystal (2, 3)

pins are not accessible. These pins

are connected internally to a coin

cell and quartz crystal. The coin cell

is sized to provide 10 years of data

retention and clock operation in the

absence of power. For a complete de-

scription of features, operating con-

ditions, electrical characteristics,

bus timing, and pin descriptions, see

the bq3285 data sheet.

Pin Names

AD0–AD7Multiplexed address/data

input/output

MOT Bus type select input

CS Chip select input

AS Address strobe input

DS Data strobe input

R/W Read/write input

INT Interrupt request output

PN328701.eps

24-Pin DIP Module

10 16

12 14

VCC

SQW

INT

RST

R/W

MOT

AD0

AD1

AD2

AD3

AD4

AD5

AD6

AD7

VSS

NC/RCL

Sept. 1996 D

RST Reset input

SQW Square wave output

NC No connect

RCL RAM clear input

(bq3287A only)

VCC +5V supply

VSS Ground

Pin Connections

bq3287/bq3287A

Real-Time Clock (RTC)Module

Not Recommended For New Designs

Sept. 1996 D

Recommended DC Operating Conditions (TA=T

OPR)

Symbol Parameter Minimum Typical Maximum Unit

VCC Supply voltage 4.5 5.0 5.5 V

VSS Supply voltage 0 0 0 V

VIL Input low voltage -0.3 - 0.8 V

VIH Input high voltage 2.2 - VCC + 0.3 V

Note: Typical values indicate operation at TA= 25°C.

Absolute Maximum Ratings

Symbol Parameter Value Unit Conditions

VCC DC voltage applied on VCC relative to VSS -0.3 to 7.0 V

VTDC voltage applied on any pin excluding VCC

relative to VSS -0.3 to 7.0 VV

≤

CC + 0.3

TOPR Operating temperature 0 to +70 °C Commercial

-20 to +70 °C Extended “I”

TSTG Storage temperature -40 to +70 °C Commercial

-40 to +70 °C Extended “I”

TBIAS Temperature under bias -10 to +70 °C Commercial

-20 to +70 °C Extended “I”

TSOLDER Soldering temperature 260 °C For 10 seconds

Note: Permanent device damage may occur if Absolute Maximum Ratings are exceeded. Functional opera-

tion should be limited to the Recommended DC Operating Conditions detailed in this data sheet. Expo-

sure to conditions beyond the operational limits for extended periods of time may affect device reliability.

DC Electrical Characteristics (TA=T

OPR,V

CC =5V±10%)

Symbol Parameter Minimum Typical Maximum Unit Conditions/Notes

ILI Input leakage current - - ±1µAV

IN =V

SS to VCC

ILO Output leakage current - - ±1µAAD0–AD7, INT and SQW

in high impedance

VOH Output high voltage 2.4 - - V IOH = -1.0 mA

VOL Output low voltage - - 0.4 V IOL = 4.0 mA

ICC Operating supply current - 7 15 mA Min. cycle, duty = 100%,

IOH = 0mA, IOL = 0mA

VSO Supply switch-over voltage - 3.0 - V

VPFD Power-fail-detect voltage 4.0 4.17 4.35 V

IRCL Input current when RCL =V

SS - - 185 µAInternal 30K pull-up

(bq3287A only)

IMOTH Input current when MOT =

VCC - - -185 µA Internal 30K pull-down

Note: Typical values indicate operation at TA= 25°C, VCC =5V.

bq3287/bq3287A

Not Recommended For New Designs

Sept. 1996 D

Power-Down/Power-Up Timing (TA=T

OPR)

Symbol Parameter Minimum Typical Maximum Unit Conditions

tFVCC slew from 4.5V to 0V 300 - - µs

tRVCC slew from 0V to 4.5V 100 - - µs

tCSR CS at VIH after power-up 20 - 200 ms Internal write-protection

period after VCC passes VPFD

on power-up.

tDR Data-retention and time-

keeping time 10 - - years TA= 25°C.

Note: Clock accuracy is better than ±1 minute per month at 25°C for the period of tDR.

Caution: Negative undershoots below the absolute maximum rating of -0.3V in battery-backup mode

may affect data integrity.

Power-Down/Power-Up Timing

bq3287/bq3287A

Not Recommended For New Designs

bq3287/bq3287A

Sept. 1996 D

24-Pin MT (T-type module)

Dimension Minimum Maximum

A 0.360 0.375

A1 0.015 -

B 0.015 0.022

C 0.008 0.013

D 1.320 1.335

E 0.685 0.700

e 0.590 0.620

G 0.090 0.110

L 0.120 0.130

S 0.100 0.120

All dimensions are in inches.

Not Recommended For New Designs

Sept. 1996 D

bq3287/bq3287A

Ordering Information

Data Sheet Revision History

Change No. Page No. Description Nature of Change

1 1 Address strobe input Clarification

1 2 Power-fail detect voltage VPFD Was 4.1 min, 4.25 max;

is 4.0 min, 4.35 max

Was : “As shipped from Benchmarq,the backup cell

is electrically isolated from the memory. ”

Is: “As shipped from Benchmarq, the backup cell is

electrically isolated from the active circuitry.” Clarification

22,4

Changed temperature from N (industrial, -40 to

+85°C) to I (extended, -20 to +70°C) Specification change

RCL max. was 275; is now 185. Pull-up = 30K

IMOTH max.was -275; is now -185. Pull-down = 30K Changed values

Notes: Change 1 = Nov. 1992 B changes from June 1991 A.

Change 2 = Nov. 1995 C changes from Nov. 1992 B.

Change 3 = Sept. 1996 D changes from Nov. 1995 C.

*Contact factory for availability.

bq3287 MT -

Package Option:

MT = T-type module

Device:

bq3287 Real-Time Clock Module

RAM Clear Option:

A = RAM clear on pin 21

no mark = No connect on pin 21

Temperature:

blank = Commercial (0 to +70°C)

I = Extended* (-20 to +70°C)

Not Recommended For New Designs

PACKAGE OPTION ADDENDUM

www.ti.com 2-Apr-2011

Addendum-Page 1

PACKAGING INFORMATION

Orderable Device Status (1) Package Type Package

Drawing Pins Package Qty Eco Plan (2) Lead/

Ball Finish MSL Peak Temp (3) Samples

(Requires Login)

BQ3287AMT-I NRND DIP MODULE MT 24 15 Pb-Free (RoHS) Call TI N / A for Pkg Type

BQ3287AMT-SB2 NRND DIP MODULE MT 24 15 Pb-Free (RoHS) Call TI N / A for Pkg Type

BQ3287MT-I NRND DIP MODULE MT 24 15 Pb-Free (RoHS) Call TI N / A for Pkg Type

BQ3287MT-SB2 NRND DIP MODULE MT 24 15 Pb-Free (RoHS) Call TI N / A for Pkg Type

(1) The marketing status values are defined as follows:

ACTIVE: Product device recommended for new designs.

LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.

NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.

PREVIEW: Device has been announced but is not in production. Samples may or may not be available.

OBSOLETE: TI has discontinued the production of the device.

(2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability

information and additional product content details.

TBD: The Pb-Free/Green conversion plan has not been defined.

Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that

lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.

Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between

the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.

Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight

in homogeneous material)

(3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.

Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information

provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and

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In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.

MECHANICAL DATA

MPDI064 – MAY 2001

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

POST OFFICE BOX 1443 • HOUSTON, TEXAS 77251–1443

MT (R-PDIP-T**) PLASTIC DUAL-IN-LINE

28 PINS SHOWN

0.110

0.130

0.022

0.013

0.390

0.630

1.335

0.740

1.535

Max.

D/28 PIN

D/24 PIN

0.710

0.090

0.110

0.590

1.520

1.320

0.015 –

Dimension

A0.015

Min.

Inches

2.79

3.30

16.00

0.56

18.80

33.91

0.33

38.99

18.03

2.29

2.79

14.99

–

0.38

33.53

38.61

Millimeters

Max.

9.91

Min.

0.38

4201978/A 03/01

0.100

S0.120 2.54 3.05

0.360 9.14

0.008 0.20

NOTES: A. All linear dimensions are in inches (mm).

B. This drawing is subject to change without notice.

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