DS1390–DS1394
Low-Voltage SPI/3-Wire RTCs with
Trickle Charger
General Description
The low-voltage serial-peripheral interface (SPI™)
DS1390/DS1391/DS1394 and the low-voltage 3-wire
DS1392/DS1393 real-time clocks (RTCs) are clocks/cal-
endars that provide hundredths of a second, seconds,
minutes, hours, day, date, month, and year information.
The date at the end of the month is automatically
adjusted for months with fewer than 31 days, including
corrections for leap year. The clock operates in either
the 24-hour or 12-hour format with an AM/PM indicator.
One programmable time-of-day alarm is provided. A
temperature-compensated voltage reference monitors
the status of V
CC
and automatically disables the bus
interface and switches to the backup supply if a power
failure is detected. On the DS1390, a single open-drain
output provides a CPU interrupt or a square wave at
one of four selectable frequencies. The DS1391
replaces the SQW/INT pin with a
RST
output/
debounced input.
The DS1390, DS1391, and DS1394 are programmed
serially through an SPI-compatible, bidirectional bus.
The DS1392 and DS1393 communicate over a 3-wire
serial bus, and the extra pin is used for either a sepa-
rate interrupt pin or a
RST
output/debounced input.
All five devices are available in a 10-pin µSOP package,
and are rated over the industrial temperature range.
o
Reset Output/Debounced Input (DS1391/DS1393)
o
Separate SQW and INT Output (DS1392)
o
Trickle-Charge Capability
o
SPI Supports Modes 0 and 2 (DS1394)
o
SPI Supports Modes 1 and 3 (DS1390/DS1391)
o
3-Wire Interface (DS1392/DS1393)
o
4MHz at 3.0V and 3.3V
o
1MHz at 1.8V
o
Three Operating Voltages: 1.8V ±5%, 3.0V ±10%,
and 2.97 to 5.5V (DS1394: 3.3V ±10%)
o
Industrial Temperature Range: -40°C to +85°C
o
Underwriters Laboratories (UL) Recognized
Ordering Information
PART
DS1390U-18+
DS1390U-3+
DS1390U-33+
DS1391U-18+
DS1391U-3+
DS1391U-33+
DS1392U-18+
DS1392U-3+
DS1392U-33+
DS1393U-18+
DS1393U-3+
DS1393U-33+
DS1394U-33+
TYP
PIN-
OPERATING
PACKAGE
VOLTAGE (V)
1.8
3.0
3.3
1.8
3.0
3.3
1.8
3.0
3.3
1.8
3.0
3.3
3.3
10 µSOP
10 µSOP
10 µSOP
10 µSOP
10 µSOP
10 µSOP
10 µSOP
10 µSOP
10 µSOP
10 µSOP
10 µSOP
10 µSOP
10 µSOP
TOP MARK†
1390 rr-18
1390 rr-3
1390 rr-33
1391 rr-18
1391 rr-3
1391 rr-33
1393 rr-18
1392 rr-3
1392 rr-33
1393 rr-18
1393 rr-3
1393 rr-33
1394 rr-33
Applications
Hand-Held Devices
GPS/Telematics Devices
Embedded Time Stamping
Medical Devices
Features
o
Real-Time Clock Counts Hundredths of Seconds,
Seconds, Minutes, Hours, Day, Date, Month, and
Year with Leap-Year Compensation Valid Up to
2100
o
Output Pin Configurable as Interrupt or Square
Wave with Programmable Frequency of
32.768kHz, 8.192kHz, 4.096kHz, or 1Hz
(DS1390/DS1393/DS1394 Only)
o
One Time-of-Day Alarm
o
Power-Fail Detect and Switch Circuitry
Note:
All devices are rated for the -40°C to +85°C operating
temperature range.
+Denotes
a lead(Pb)-free/RoHS-compliant package.
†A
“+” anywhere on the top mark denotes a lead(Pb)-
free/RoHS-compliant package.
rr = Revision code on second line of top mark.
Typical Operating Circuits and Pin Configurations appear at
end of the data sheet.
SPI is a trademark of Motorola, Inc.
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
19-4898; Rev 4; 10/12
DS1390–DS1394
Low-Voltage SPI/3-Wire RTCs with
Trickle Charger
ABSOLUTE MAXIMUM RATINGS
Voltage Range on V
CC
Pin Relative to Ground .....-0.3V to +6.0V
Voltage Range on Inputs Relative
to Ground ...............................................-0.3V to (V
CC
+ 0.3V)
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-55°C to +125°C
Soldering Temperature...........................Refer to the IPC/JEDEC
J-STD-020 Specification.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
RECOMMENDED DC OPERATING CONDITIONS
(V
CC
= V
CC(MIN)
to V
CC(MAX)
, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at nominal supply voltage and T
A
= +25°C,
unless otherwise noted.) (Note 1)
PARAMETER
Supply Voltage (Note 2)
SYMBOL
DS139x-33
V
CC
DS139x-3
DS139x-18
Logic 1
Logic 0
Supply Voltage, Pullup
SQW/INT, SQW,
INT,
V
CC
= 0V
V
BACKUP
Voltage (Note 2)
V
IH
V
IL
V
PU
(Note 2)
(Note 2)
(Note 2)
-33
V
BACKUP
-3
-18
-33
Power-Fail Voltage (Note 2)
V
PF
R1
Trickle-Charge Current-Limiting
Resistors
Input Leakage
I/O Leakage
RST
Pin I/O Leakage
DOUT Logic 1 Output
DOUT Logic 0 Output
Logic 0 Output
(DS1390/DS1393/DS1394
SQW/INT; DS1392 SQW,
INT;
DS1391/DS1393
RST)
V
CC
Active Supply Current
(Note 10)
R2
R3
I
LI
I
LO
I
LORST
I
OHDOUT
I
OHDOUT
-3
-18
(Notes 3, 4)
(Notes 3, 5)
(Notes 3, 6)
(Note 7)
(Note 8)
(Note 9)
-33, -3 (V
OH
= 0.85 x V
CC
)
-18 (V
OH
= 0.80 x V
CC
)
-33, -3 (V
OL
= 0.15 x V
CC
)
-18 (V
OL
= 0.20 x V
CC
)
V
CC
> 1.71V; V
OL
= 0.4V
I
OLSIR
1.3V < V
CC
< 1.71V; V
OL
= 0.4V
-33
I
CCA
-3
-18
2
CONDITIONS
MIN
2.97
2.7
1.71
0.7 x
V
CC
-0.3
TYP
3.3
3.0
1.8
MAX
5.50
3.3
1.89
V
CC
+
0.5
+0.3 x
V
CC
5.5
UNITS
V
V
V
V
1.3
1.3
1.3
2.70
2.45
1.51
3.0 V
CC(MAX)
3.0
3.0
2.88
2.6
1.6
250
2000
4000
3.7
3.7
2.97
2.70
1.71
V
V
-1
-1
-200
+1
+1
+10
-1
0.750
3
2
3.0
250
2
2
500
µA
µA
µA
mA
mA
mA
µA
mA
µA
Maxim Integrated
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