Real-Time Clock with Battery 1338 Backed Non-Volatile RAM Datasheet Description Features The 1338 is a serial real-time clock (RTC) device that Real-Time Clock (RTC) counts seconds, minutes, hours, consumes ultra-low power and provides a full binary-coded day, date, month, and year with leap-year compensation decimal (BCD) clock/calendar with 56 bytes of battery valid up to 2100 backed Non-Volatile Static RAM. The clock/calendar 56-byte battery-backed Non-Volatile RAM for data provides seconds, minutes, hours, day, date, month, and storage year information. The clock operates in either the 24-hour 2 or 12-hour format with AM/PM indicator. The end of the Fast mode I C serial interface month date is automatically adjusted for months with fewer Automatic power-fail detect and switch circuitry than 31 days, including corrections for leap year. Access to 2 Programmable square-wave output the clock/calendar registers is provided by an I C interface 2 capable of operating in fast I C mode. Built-in Power-sense Packaged in 8-pin MSOP, 8-pin SOIC, or 16-pin SOIC circuitry detects power failures and automatically switches (surface-mount package with an integrated crystal) to the backup supply, maintaining time and date operation. Industrial temperature range (-40C to +85C) Typical Applications Telecom (Routers, Switches, Servers) Handheld (GPS, Point of Sale POS Terminals) Consumer Electronics (Set-Top Box, Digital Recording, Network Applications, Digital Photo Frames) Office (Fax/Printers, Copiers) Medical (Glucometer, Medicine Dispensers) Other (Thermostats, Vending Machines, Modems, Utility Meters) Block Diagram Crystal inside package for 16-pin SOIC ONLY 1Hz / 4.096kHz / 8.192kHz / 32.768kHz X1 32.768kHz MUX/ Oscillator and SQW/OUT Buffer Divider X2 VCC Power Control Clock, Calendar GND Control Logic Counter V BAT SCL 2 I C 56 Byte 1 Byte 7 Bytes Interface RAM Control Buffer SDA 2020 Renesas Electronics Corporation 1 September 30, 20201338 Datasheet Pin Assignment (8-pin MSOP/8-pin SOIC) Pin Assignment (16-pin SOIC) 1 16 SCL SDA X1 8 1 VCC SQW/OUT 15 2 GND X2 2 IDT 7 SQW/OUT VCC V 1338 3 14 BAT V 3 6 BAT SCL IDT 4 13 NC NC GND 4 5 SDA 1338C 5 NC NC 12 NC 6 NC 11 7 NC 10 NC 8 NC 9 NC Pin Descriptions Pin Number Pin Pin Description/Function Name 8MSOP, 16SOIC 8SOIC 1 X1 Connections for standard 32.768kHz quartz crystal. The internal oscillator circuitry is designed for operation with a crystal having a specified load capacitance (CL) of 12.5pF. An external 2 X2 32.768kHz oscillator can also drive the IDT1338. In this configuration, the X1 pin is connected to the external oscillator signal and the X2 pin is left floating. 3 14 V Backup Supply Input for Lithium Coin Cell or Other Energy Source. Battery voltage must be held BAT between the minimum and maximum limits for proper operation. Diodes placed in series between the backup source and the V pin may prevent proper operation. If a backup supply BAT is not required, V must be connected to ground. BAT 4 15 GND Connect to ground. 2 5 16 SDA Serial data input/output. SDA is the input/output pin for the I C serial interface. It is an open-drain output and requires an external pull-up resistor (2kOhm 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 (2kOhm typical) 7 2 SQW/OUT Square-Wave/Output driver. When enabled and the SQWE bit set to 1, the SQW/OUT pin outputs one of four square-wave frequencies (1Hz, 4kHz, 8kHz, 32kHz). It is an open drain output and requires an external pull-up resistor (10K ohm typical). Operates when the device is powered with VCC or V . BAT 8 3 V Device power supply. When voltage is applied within specified limits, the device is fully CC 2 accessible by I C and data can be written and read. 4 13 NC No connect. These pins are unused and must be connected to ground for proper operation. 2020 Renesas Electronics Corporation 2 September 30, 2020