DS1390, DS1391, DS1392, DS1393 Low-Voltage SPI/3-Wire RTCs with Trickle Charger

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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, 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/active-low INT pin with an active-low 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 an active-low RST output/debounced input.

All four devices are available in a 10-pin µSOP package, and are rated over the industrial temperature range.

Key Features

Applications/Uses

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

	Embedded Time Stamping
	GPS/Telematics Devices
	Handheld Devices
	Medical Devices

Key Specifications: Timekeeping & Real-Time Clocks

Part Number

Time Format (hh = sec/100)

Date Format

Interface

Supply Voltage (V)

Time- keeping Current (typ) (nA)

C_L, Load Capacitance (pF)

Memory Type

Number of Time of Day Alarms

Features

RoHS Available

Package

Smallest Available Package (max w/pins) (mm²)

Operating Temp. Range (°C)

Price^*

DS1390

HH:MM:SS:hh

YY-MM-DD

SPI

1.8
3
3.3
5

500

None

•	Square-Wave Output

•	Trickle Charger

Yes

uSOP/10

-40 to +85

$1.25 @ 1k

DS1391

SPI

•

µP Reset

•	Power Fail Output

•	Trickle Charger

$1.25 @ 1k

DS1392

3-Wire

•	Square-Wave Output

•	Trickle Charger

$1.25 @ 1k

DS1393

3-Wire

•

µP Reset

•	Power Fail Output

•	Trickle Charger

$1.25 @ 1k

See All Timekeeping & Real-Time Clocks (87)

Notes:
^*This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific prices and delivery, please see the price and availability page or contact an authorized distributor.