Intersil Corporation introduced the ISL1208 Real Time Clock (RTC) that combines high-precision and low-power consumption. In addition, the device incorporates Intersil’s InterSeal battery saver technology, which prevents any current drain on the battery until the unit is first powered up. The InterSeal feature is an obvious benefit for products that might be stored for some time before they are first used.
The ISL1208 device is a low power real time clock with timing and crystal compensation, clock/calendar, power fail indicator, periodic or polled alarm, intelligent battery backup switching and battery-backed user SRAM. With analog trimming register (ATR) and digital trimming register (DTR) functions, external crystal frequencies can be tuned. It features an I2C interface that provides 400kHz data transfer rate. The device supports 15 selectable frequency outputs, power failure detection and automatic backup to battery or Super Cap.
The ISL1208 contains circuitry for adjusting the frequency of the crystal oscillator. This circuitry can be used to tune oscillator frequency, critical in compensating for PCB layout and temperature changes. The oscillator uses an external 32.768kHz crystal. The real time clock tracks time with separate registers for hours, minutes and seconds. The device has calendar registers for date, month, year and day of the week. The calendar is accurate through 2099, with automatic leap year correction.
For microprocessor and other timing applications, the real time clocks can provide one of 15 different frequency output signals via the IRQ/Fout pin. Users have access to 2 bytes of battery-backed SRAM that can be used for scratchpad memory. Applications with a limited power budget can utilize the device’s low power mode for a supply current saving of about 400nA when powered from VDD. The ISL1208 is functionally compatible to the ST M41Txx and Maxim DS13xx devices.
The ISL1208 is available now, in either standard lead finish or Pb-free. The ISL1208 is offered in an 8-lead SOIC package and in 1,000-unit volumes is priced at $1.10 each; in 8-lead MSOP packages the price is $1.20 each.
