DS1390 Datasheet, PDF (1/24 Pages) Maxim Integrated Products – Low-Voltage SPI/3-Wire RTCs with Trickle Charger

Rev 0; 7/04
Low-Voltage SPI/3-Wire RTCs with
Trickle Charger
General Description
The low-voltage serial-peripheral interface (SPI™)
DS1390/DS1391 and the low-voltage 3-wire DS1392/
DS1393 real-time clocks (RTCs) are clocks/calendars
that provide hundredths of a second, seconds, min-
utes, 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 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 fre-
quencies. The DS1391 replaces the SQW/INT pin with a
RST output/debounced input.
The DS1390 and DS1391 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 separate
interrupt pin or a RST output/debounced input.
All four devices are available in a 10-pin µSOP package,
and are rated over the industrial temperature range.
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 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 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
♦ Industrial Temperature Range: -40°C to +85°C
♦ Underwriters Laboratory (UL) Recognized
Applications
Hand-Held Devices
GPS/Telematics Devices
Embedded Time Stamping
Medical Devices
Typical Operating Circuits and Pin Configurations appear at
end of the data sheet.
Ordering Information
PART
TEMP RANGE
PIN-
PACKAGE
TOP MARK
DS1390U-18 -40°C to +85°C 10 µSOP DS1390 rr-18
DS1390U-3
-40°C to +85°C 10 µSOP DS1390 rr-3
DS1390U-33 -40°C to +85°C 10 µSOP DS1390 rr-33
DS1391U-18 -40°C to +85°C 10 µSOP DS1391 rr-18
DS1391U-3
-40°C to +85°C 10 µSOP DS1391 rr-3
DS1391U-33 -40°C to +85°C 10 µSOP DS1391 rr-33
DS1392U-18 -40°C to +85°C 10 µSOP DS1393 rr-18
DS1392U-3
-40°C to +85°C 10 µSOP DS1392 rr-3
DS1392U-33 -40°C to +85°C 10 µSOP DS1392 rr-33
DS1393U-18 -40°C to +85°C 10 µSOP DS1393 rr-18
DS1393U-3
-40°C to +85°C 10 µSOP DS1393 rr-3
DS1393U-33 -40°C to +85°C 10 µSOP DS1393 rr-33
Where “rr” is a revision code on the second line of the top mark.
SPI is a trademark of Motorola, Inc.
______________________________________________ Maxim Integrated Products 1
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