TI BQ3287EMT Real-time clock rtc module Datasheet

bq3287E/bq3287EA
Real-Time Clock (RTC) Module
Features
➤ Direct clock/calendar replacement for IBM ® AT-compatible
computers and other applications
➤ Functionally compatible with
the DS1287/DS1287A and
MC146818A/ MC146818B
➤ 242 bytes of general nonvolatile
storage
➤ Calendar in day of the week, day
of the month, months, and years
with automatic leap-year adjustment
➤ Programmable square wave output
➤ Three individually maskable interrupt event flags:
➤ Provides a 32.768kHz output for
power management
➤ System wake-up capability—
al arm int e r r upt ac t iv e
battery-backup mode
➤ 160 ns cycle time allows fast bus
operation
➤ 14 bytes for clock/calendar and
control
➤ Time of day in seconds, minutes,
and hours
12- or 24-hour format
-
Optional daylight saving
adjustment
Pin Connections
MOT
NC
NC
AD0
AD1
AD2
AD3
AD4
AD5
AD6
AD7
VSS
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
Periodic rates from 122µs to
500ms
-
Time-of-day alarm once per
second to once per day
-
End-of-clock update cycle
in
➤ Integral lithium cell and crystal
-
-
➤ Better than one minute per
month clock accuracy
General Description
The CMOS bq3287E/bq3287EA is a
low-power microprocessor peripheral providing a time-of-day clock
and 100-year calendar with alarm
features and battery operation.
O t he r f e a tu re s i n cl u d e th re e
maskable interrupt sources, squarewave output, and 242 bytes of gene r al n o n v o l a ti l e s to ra g e. A
32.768kHz output is available for
sustaining power-management activities. Wake-up capability is pro-
vided by an alarm interrupt, which is
active in battery-backup mode. The
bq3287EA version is identical to the
bq3287E, with the addition of the
RAM clear input.
The bq3287E is a fully compatible
real-time clock for IBM AT-compatible
computers and other applications. The
bq3287E write-protects the clock, calendar, and storage registers during
power failure. The integral backup energy source then maintains data and
operates the clock and calendar.
As shipped from Benchmarq, the
real time clock is turned off to maximize battery capacity for in-system
operation.
The bq3287E is functionally equivalent to the bq3285E, except the battery (16,20) and crystal pins (2,3)
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 description of features, operating conditions, electrical characteristics,
bus timing, and pin descriptions, see
the bq3285E data sheet.
Pin Names
VCC
SQW
EXTRAM
NC/RCL
NC
INT
RST
DS
NC
R/W
AS
CS
24-Pin DIP Module
AD0–AD7 Multiplex address/data
input/output
MOT
CS
Chip select input
AS
Address strobe input
DS
Data strobe input
R/W
Read/write input
INT
Interrupt request output
PN3287E1.eps
Sept. 1996 C
1
RST
Reset input
SQW
Square wave output
EXTRAM Extended RAM enable
NC
No connect
RCL
RAM clear input
(bq3287EA only)
VCC
+5V supply
VSS
Ground
bq3287E/bq3287EA
Absolute Maximum Ratings
Symbol
Parameter
Value
Unit
Conditions
VCC
DC voltage applied on VCC relative to VSS
-0.3 to 7.0
V
VT
DC voltage applied on any pin excluding VCC
relative to VSS
-0.3 to 7.0
V
VT ≤ VCC + 0.3
TOPR
Operating temperature
0 to +70
°C
Commercial
TSTG
Storage temperature
-40 to +70
°C
Commercial
TBIAS
Temperature under bias
-10 to +70
°C
Commercial
TSOLDER
Soldering temperature
260
°C
For 10 seconds
Note:
Permanent device damage may occur if Absolute Maximum Ratings are exceeded. Functional operation
should be limited to the Recommended DC Operating Conditions detailed in this data sheet. Exposure to
conditions beyond the operational limits for extended periods of time may affect device reliability.
Recommended DC Operating Conditions (TA = TOPR)
Minimum
Typical
Maximum
Unit
VCC
Symbol
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:
Parameter
Typical values indicate operation at TA = 25°C.
DC Electrical Characteristics (TA = TOPR, VCC = 5V ± 10%)
Symbol
Parameter
Minimum
Typical
Maximum
Unit
Conditions/Notes
ILI
Input leakage current
-
-
±1
µA
VIN = VSS to VCC
ILO
Output leakage current
-
-
±1
µA
AD0–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
VSO
Supply switch-over voltage
VPFD
Power-fail-detect voltage
IRCL
IMOTH
IXTRAM
Note:
Min. cycle, duty = 100%,
IOH = 0mA, IOL = 0mA
-
3.0
-
V
4.0
4.17
4.35
V
Input current when RCL = VSS
-
-
185
µA
Internal 30K pull-up
(bq3287EA only)
Input current when MOT =
VCC
-
-
-185
µA
Internal 30K pull-down
-
-
-185
µA
Internal 30K pull-down
Input current when
EXTRAM = VCC
Typical values indicate operation at TA = 25°C, VCC = 5V.
Sept. 1996 C
2
bq3287E/bq3287EA
Power-Down/Power-Up Timing
Symbol
(TA = TOPR)
Parameter
Minimum
Typical
Maximum
Unit
tF
VCC slew from 4.5V to 0V
300
-
-
µs
tR
VCC slew from 0V to 4.5V
100
-
-
µs
tCSR
CS at VIH after power-up
20
-
200
ms
tDR
Data-retention and timekeeping time
10
-
-
years
Note:
Conditions
Internal write-protection
period after VCC passes VPFD
on power-up.
TA = 25°C.
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
Sept. 1996 C
3
bq3287E/bq3287EA
24-Pin MT (T-type module)
24-Pin MT (T-Type Module)
Inches
Millimeters
Dimension
A
Min.
Max.
Min.
Max.
0.360
0.390
9.14
9.91
A1
0.015
-
0.38
-
B
0.015
0.022
0.38
0.56
C
0.008
0.013
0.20
0.33
D
1.320
1.335
33.53
33.91
E
0.710
0.740
18.03
18.80
e
0.590
0.620
14.99
15.75
G
0.090
0.110
2.29
2.79
L
0.110
0.130
2.79
3.30
S
0.100
0.120
2.54
3.05
Sept. 1996 C
4
bq3287E/bq3287EA
Data Sheet Revision History
Change No.
Page No.
1
8
Register C, bit 2
2
2
IRCL max. was 275; is now 185. Pull-down = 30K. Value change
2
2
IXTRAM max. was -75; is now -185.
Notes:
Description
Nature of Change
Was 0; is na (not affected)
Value change
Change 1 = Apr. 1994 B “Final” changes from Dec. 1993 A “Preliminary.”
Change 2 = Sept. 1996 C changes from April 1994 B.
Ordering Information
bq3287E
MT Temperature:
blank = Commercial (0 to +70°C)
Package Option:
MT = T-type module
RAM Clear Option:
A = RAM clear on pin 21
no mark = No connect on pin 21
Device:
bq3287E Real-Time Clock Module
Sept. 1996 C
5
PACKAGE OPTION ADDENDUM
www.ti.com
4-Mar-2005
PACKAGING INFORMATION
Orderable Device
Status (1)
BQ3287EAMT
ACTIVE
0
1
None
Call TI
Call TI
BQ3287EMT
ACTIVE
0
1
None
Call TI
Call TI
Package
Type
Package
Drawing
Pins Package Eco Plan (2)
Qty
Lead/Ball Finish
MSL Peak Temp (3)
(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 - May not be currently available - please check http://www.ti.com/productcontent for the latest availability information and additional
product content details.
None: Not yet available Lead (Pb-Free).
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.
Green (RoHS & no Sb/Br): TI defines "Green" to mean "Pb-Free" and in addition, uses package materials that do not contain halogens,
including bromine (Br) or antimony (Sb) above 0.1% of total product weight.
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDECindustry standard classifications, and peak solder
temperature.
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Addendum-Page 1
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