TI BQ3287MT-SB2 Real-time clock rtc module Datasheet

bq3287/bq3287A
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
➤ 114 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:
➤ Integral lithium cell and crystal
➤ 160 ns cycle time allows fast bus
operation
➤ Selectable Intel or Motorola bus
timing
-
Periodic rates from 122 µs to
500 ms
-
Time-of-day alarm once per
second to once per day
-
End-of-clock update cycle
➤ 14 bytes for clock/calendar and
control
➤ Better than one minute per
month clock accuracy
➤ BCD or binary format for clock
and calendar data
General Description
➤ 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
The CMOS bq3287/bq3287A 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 114 bytes of gene r al n o n volatile storage. The
bq3287A version is identical to the
bq3287, with the addition of the RAM
clear input.
The bq3287 is a fully compatible
r e a l - t i m e c l o c k f o r I B M ATcompatible computers and other app l i c a t i o n s. T h e b q 3 2 8 7 w r i t e 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 bq3287 is functionally equivalent 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 description of features, operating conditions, electrical characteristics,
bus timing, and pin descriptions, see
the bq3285 data sheet.
Pin Names
VCC
SQW
NC
NC/RCL
NC
INT
RST
DS
NC
R/W
AS
CS
AD0–AD7
Multiplexed 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
24-Pin DIP Module
PN328701.eps
Sept. 1996 D
1
RST
Reset input
SQW
Square wave output
NC
No connect
RCL
RAM clear input
(bq3287A only)
VCC
+5V supply
VSS
Ground
bq3287/bq3287A
Absolute Maximum Ratings
Value
Unit
VCC
Symbol
DC voltage applied on VCC relative to VSS
Parameter
-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
-20 to +70
°C
Extended “I”
-40 to +70
°C
Commercial
-40 to +70
°C
Extended “I”
-10 to +70
°C
Commercial
-20 to +70
°C
Extended “I”
260
°C
For 10 seconds
Storage temperature
TSTG
Temperature under bias
TBIAS
Soldering temperature
TSOLDER
Note:
Conditions
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)
Symbol
Parameter
Minimum
Typical
Maximum
Unit
4.5
5.0
5.5
V
0
0
0
V
-0.3
-
0.8
V
-
VCC + 0.3
V
VCC
Supply voltage
VSS
Supply voltage
VIL
Input low voltage
VIH
Input high voltage
2.2
Note:
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
-
3.0
-
V
VPFD
Power-fail-detect voltage
4.0
4.17
4.35
V
IRCL
Input current when RCL = VSS
-
-
185
µA
Internal 30K pull-up
(bq3287A only)
IMOTH
Input current when MOT =
VCC
-
-
-185
µA
Internal 30K pull-down
Note:
Min. cycle, duty = 100%,
IOH = 0mA, IOL = 0mA
Typical values indicate operation at TA = 25°C, VCC = 5V.
Sept. 1996 D
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bq3287/bq3287A
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 D
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bq3287/bq3287A
24-Pin MT (T-type module)
24-Pin MT (T-type module)
Dimension
A
A1
B
C
D
E
e
G
L
S
Minimum
0.360
0.015
0.015
0.008
1.320
0.685
0.590
0.090
0.120
0.100
Maximum
0.375
0.022
0.013
1.335
0.700
0.620
0.110
0.130
0.120
All dimensions are in inches.
Sept. 1996 D
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bq3287/bq3287A
Data Sheet Revision History
Change No.
Page No.
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
2
1
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
2
2, 4
Changed temperature from N (industrial, -40 to
+85°C) to I (extended, -20 to +70°C)
Specification change
3
2
Notes:
Description
Nature of Change
IRCL max. was 275; is now 185. Pull-up = 30K
IMOTH max. was -275; is now -185. Pull-down = 30K Changed values
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.
Ordering Information
bq3287
MT Temperature:
blank = Commercial (0 to +70°C)
I = Extended* (-20 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:
bq3287 Real-Time Clock Module
*Contact factory for availability.
Sept. 1996 D
5
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