Description

         The low-voltage serial-peripheral interface (SPI™) AT8590/AT8591/AT8594 and the low-voltage 3-wire AT8592/AT8593 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 AT8590, a single open-drain output provides a CPU interrupt or a square wave at  one of four selectable frequencies. The AT8591 replaces the  SQW/INT  pin  with  a RST output/debounced input.

         The AT8590, AT8591, and AT8594 are programmed serially through an SPI-compatible, bidirectional bus.  The AT8592 and AT8593 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, andYear with Leap-Year Compensation Valid Up to 2100

• Output Pin Configurable as Interrupt or Square Wave with Programmable Frequency of32.768kHz, 8.192kHz, 4.096kHz, or 1Hz (AT8590/AT8593/AT8594 Only)

• One Time-of-Day Alarm

• Power-Fail Detect and Switch Circuitry

• Reset Output/Debounced Input (AT8591/AT8593)

• Separate SQW and INT Output (AT8592)

• Trickle-Charge Capability

• SPI Supports Modes 0 and 2 (AT8594)

• SPI Supports Modes 1 and 3 (AT8590/AT8591)

• 3-Wire Interface (AT8592/AT8593)

• 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 (AT8594: 3.3V ±10%)

• Industrial Temperature Range: -40°C to +85°C