DS1390_09 Datasheet, PDF (1/26 Pages) Maxim Integrated Products – Low-Voltage SPI/3-Wire RTCs with Trickle Charger

19-4898; Rev 3; 8/09
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.
Applications
Hand-Held Devices
GPS/Telematics Devices
Embedded Time Stamping
Medical Devices
Features
♦ Real-Time Clock Counts Hundredths of Seconds,
Seconds, Minutes, Hours, Day, Date, Month, and
Year with Leap-Year Compensation Valid Up to
2100
♦ Output Pin Configurable as Interrupt or Square
Wave with Programmable Frequency of
32.768kHz, 8.192kHz, 4.096kHz, or 1Hz
(DS1390/DS1393/DS1394 Only)
♦ One Time-of-Day Alarm
♦ Power-Fail Detect and Switch Circuitry
♦ Reset Output/Debounced Input (DS1391/DS1393)
♦ Separate SQW and INT Output (DS1392)
♦ Trickle-Charge Capability
♦ SPI Supports Modes 0 and 2 (DS1394)
♦ SPI Supports Modes 1 and 3 (DS1390/DS1391)
♦ 3-Wire Interface (DS1392/DS1393)
♦ 4MHz at 3.0V and 3.3V
♦ 1MHz at 1.8V
♦ Three Operating Voltages: 1.8V ±5%, 3.0V ±10%,
and 2.97 to 5.5V (DS1394: 3.3V ±10%)
♦ Industrial Temperature Range: -40°C to +85°C
♦ Underwriters Laboratories (UL) Recognized
Ordering Information
PART
TYP
OPERATING
VOLTAGE (V)
PIN-
PACKAGE
TOP MARK†
DS1390U-18+
1.8
10 μSOP 1390 rr-18
DS1390U-3+
3.0
10 μSOP 1390 rr-3
DS1390U-33+
3.3
10 μSOP 1390 rr-33
DS1390U-33/V+
3.3
10 μSOP 1390 rr-33
DS1391U-18+
1.8
10 μSOP 1391 rr-18
DS1391U-3+
3.0
10 μSOP 1391 rr-3
DS1391U-33+
3.3
10 μSOP 1391 rr-33
DS1392U-18+
1.8
10 μSOP 1393 rr-18
DS1392U-3+
3.0
10 μSOP 1392 rr-3
DS1392U-33+
3.3
10 μSOP 1392 rr-33
DS1393U-18+
1.8
10 μSOP 1393 rr-18
DS1393U-3+
3.0
10 μSOP 1393 rr-3
DS1393U-33+
3.3
10 μSOP 1393 rr-33
DS1394U-33+
3.3
10 μSOP 1394 rr-33
Note: All devices are rated for the -40°C to +85°C operating
temperature range.
+Denotes a lead(Pb)-free/RoHS-compliant package.
/V denotes an automotive qualified part.
†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.
______________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.