DATASHEET 2 REAL-TIME CLOCK WITH SERIAL I C INTERFACE IDT1339 General Description Features The IDT1339 serial real-time clock (RTC) is a low-power Real-Time Clock (RTC) counts seconds, minutes, hours, clock/date device with two programmable time-of-day day, date, month, and year with leap-year compensation alarms and a programmable square-wave output. Address valid up to 2100 2 and data are transferred serially through an I C bus. The Packaged in 8-pin MSOP, 8-pin SOIC, or 16-pin SOIC clock/date provides seconds, minutes, hours, day, date, (surface-mount package with an integrated crystal) month, and year information. The date at the end of the 2 Fast mode I C Serial interface month is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock Two time-of-day alarms operates in either the 24-hour or 12-hour format with Programmable square-wave output AM/PM indicator. The IDT1339 has a built-in power-sense Oscillator stop flag circuit that detects power failures and automatically switches to the backup supply, maintaining time, date, and Automatic power-fail detect and switch circuitry alarm operation. Trickle-charge capability Applications Industrial temperature range (-40 to +85C) Underwriters Laboratory (UL) recognized Handhelds (GPS, POS terminals) Consumer Electronics (Set-Top Box, Digital Recording, Network Applications) Office (Fax/Printers, Copiers) Medical (Glucometer, Medicine Dispensers) Telecomm (Routers, Switches, Servers) Other (Thermostats, Vending Machines, Modems, Utility Meters) Block Diagram Crystal inside package for 16-pin SOIC ONLY 1 Hz/4.096 kHz/ 8.192 kHz/32.768 kHz X1 MUX/ 32.768 kHz SQW/INT Buffer Oscillator and Divider X2 GND Clock, Control VCC Calendar Power Logic Counter Trickle Control Charger V BACKUP SCL 2 I C 1 Byte 7 Bytes 7 Bytes 1 Byte Interface Control Buffer Alarm Status SDA 2 IDT REAL-TIME CLOCK WITH SERIAL I C INTERFACE 1 IDT1339 REV S 031014 Trickle Charger ByteIDT1339 2 REAL-TIME CLOCK WITH SERIAL I C INTERFACE RTC Pin Assignment (8-pin MSOP/8-pin SOIC) Pin Assignment (16-pin SOIC) X1 8 16 1 VCC SCL 1 SDA X2 SQW/INT 15 2 IDT 7 SQW/INT 2 GND V 1339 VCC 14 V BACKUP 3 6 3 SCL BACKUP IDT GND 5 13 4 SDA NC 4 NC 1339C 5 NC NC 12 NC 6 NC 11 NC 7 NC 10 8 NC 9 NC Pin Descriptions Pin Pin Number Pin Description/Function Name MSOP SOIC 1 X1 Connections for standard 32.768 kHz quartz crystal. The internal oscillator circuitry is designed for operation with a crystal having a specified load capacitance (CL) of 7 pF. An 2 X2 external 32.768 kHz oscillator can also drive the IDT1339. In this configuration, the X1 pin is connected to the external oscillator signal and the X2 pin is left floating. 314 V Backup supply input. Supply voltage must be held between 1.3 V and 3.7 V for proper BACKUP operation. This pin can be connected to a primary cell, such as a lithium button cell. Additionally, this pin can be connected to a rechargeable cell or a super cap that can be charged using the trickle charger circuit. Diodes placed in series between the backup source and the VBAT pin may prevent proper operation. If a backup supply is not required, VBAT must be connected to ground. UL recognized to ensure against reverse charged current when used with a lithium cell. 4 15 GND Connect to ground. DC power is provided to the device on these pins. 2 5 16 SDA Serial data input/output. SDA is the input/output pin for the I C serial interface. The SDA pin is an open-drain output and requires an external pull-up resistor (2 k typical). 6 1 SCL Serial clock input. SCL is used to synchronize data movement on the serial interface. It is an open-drain output and requires an external pull-up resistor (2 k typical). 72 SQW/INT Square-Wave/Interrupt output. Programmable square-wave or interrupt output signal. The SQW/INT pin is an open-drain output and requires an external pull-up resistor (10 k typical). 83 V Primary power supply. When voltage is applied within normal limits, the device is fully CC accessible and data can be written and read. 4 - 13 NC No connect. These pins are unused and must be connected to ground. 2 IDT REAL-TIME CLOCK WITH SERIAL I C INTERFACE 2 IDT1339 REV S 031014