DATASHEET ISL12022MA FN7575 Rev 5.00 Low Power RTC with Battery Backed SRAM, Integrated 5ppm Temperature September 5, 2012 Compensation and Auto Daylight Saving The ISL12022MA device is a low power real time clock (RTC) Features with an embedded temperature sensor and crystal. Device Embedded 32.768kHz Quartz Crystal in the Package functions include oscillator compensation, clock/calendar, power fail and low battery monitors, brownout indicator, 20 Ld SOIC Package (for DFN version, refer to the one-time, periodic or polled alarms, intelligent battery backup ISL12020M) switching, Battery Reseal function and 128 bytes of Calendar battery-backed user SRAM. Backup battery current draw is less On-chip Oscillator Temperature Compensation than 1.6A over the temperature range. The device is offered in 10-bit Digital Temperature Sensor Output a 20 Ld SOIC module that contains the RTC and an embedded 32.768kHz quartz crystal. The calibrated oscillator provides less 15 Selectable Frequency Outputs than 5ppm drift over the full -40C to +85C temperature Interrupt for Alarm or 15 Selectable Frequency Outputs range. Automatic Backup to Battery or Supercapacitor The RTC tracks time with separate registers for hours, minutes, V and Battery Status Monitors DD and seconds. The calendar registers track date, month, year and Battery Reseal Function to Extend Battery Shelf Life day of the week and are accurate through 2099, with automatic Power Status Brownout Monitor leap year correction. Time Stamp for Battery Switchover Daylight Savings time adjustment is done automatically, using 128 Bytes Battery-Backed User SRAM parameters entered by the user. Power fail and battery monitors offer user-selectable trip levels. The time stamp function records 1.6A Max Battery Current the time and date of switchover from V to V power, and 2 DD BAT I C Bus also from V to V power. BAT DD RoHS Compliant The ISL12022MA features enhanced immunity to ESD per the IEC61000-4-2 standard, and also provides improved resistance Applications to system leakage related to environmental moisture. Utility Meters POS Equipment Related Literature Printers and Copiers See TB484 ISL12022MA Enhanced RTC Module Digital Cameras See AN1549 Addressing Power Issues in Real Time Clock Applications 1 20 GND GND 2 19 GND GND 3 18 GND GND 3.3V 4 17 NC NC 5 16 NC NC C1 SCHOTTKY DIODE 6 15 R1 R2 R3 NC 0.1F BAT54 NC 10k 10k 10k 7 14 V V BAT DD 8 13 BATTERY C2 VDO IRQ/F GND OUT 0.1F 3.0V 9 12 NC SCL SCL MCU 10 11 INTERFACE SDA NC SDA ISL12022MA GND IRQ/F OUT FIGURE 1. TYPICAL APPLICATION CIRCUIT FN7575 Rev 5.00 Page 1 of 31 September 5, 2012ISL12022MA Block Diagram SDA SDA SECONDS BUFFER 2 I C CONTROL INTERFACE SCL MINUTES SCL LOGIC BUFFER REGISTERS HOURS DAY OF WEEK CRYSTAL RTC DATE OSCILLATOR DIVIDER MONTH V YEAR DD POR FREQUENCY ALARM OUT CONTROL V REGISTERS TRIP + USER SWITCH - SRAM V INTERNAL BAT IRQ/F SUPPLY OUT FREQUENCY TEMPERATURE GND CONTROL SENSOR Pin Configuration ISL12022MA (20 LD SOIC) TOP VIEW GND 1 20 GND GND 2 19 GND GND 3 18 GND 4 17 NC NC 5 16 NC NC NC 6 15 NC V 7 14 V BAT DD 8 13 IRQ/F GND OUT 9 12 NC SCL 10 11 NC SDA Pin Descriptions PIN NUMBER SYMBOL DESCRIPTION 4, 5, 6, 9, 10, NC No Connection. Do not connect to a signal or supply voltage. 15, 16, 17 7V Backup Supply. This input provides a backup supply voltage to the device. VBAT supplies power to the device in the event BAT that the VDD supply fails. This pin can be connected to a battery, a supercapacitor or tied to ground if not used. See the Battery Monitor parameter in the table on page 6. This pin should be tied to ground if not used. 11 SDA Serial Data. SDA is a bi-directional pin used to transfer data into and out of the device. It has an open drain output and may be ORed with other open drain or open collector outputs. The input buffer is always active (not gated) in normal mode. An open drain output requires the use of a pull-up resistor. The output circuitry controls the fall time of the output signal 2 with the use of a slope controlled pull-down. The circuit is designed for 400kHz I C interface speeds. It is disabled when the backup power supply on the VBAT pin is activated. 12 SCL Serial Clock. The SCL input is used to clock all serial data into and out of the device. The input buffer on this pin is always active (not gated). It is disabled when the backup power supply on the VBAT pin is activated to minimize power consumption. FN7575 Rev 5.00 Page 2 of 31 September 5, 2012