ISL1218 is a low power real time clock from Intersil with timing and crystal compensation, clock/calendar, power fail indicator, periodic or polled alarm, intelligent battery backup switching and battery-backed user SRAM.
The ISL1218 is a low‑power real‑time clock with calendar, alarm, and 8‑byte battery‑backed SRAM. It uses an external 32.768 kHz crystal and offers automatic leap‑year correction, power‑fail detection, and selectable frequency outputs. The device operates from 2.0 V to 5.5 V and can be backed up by a battery or super‑capacitor.
The datasheet includes pin‑out diagrams, absolute maximum ratings, DC operating characteristics, serial‑interface specifications, and package dimensions for both MSOP and SOIC options. Application notes cover utility meters, HVAC equipment, audio/video components, and other industrial uses.
| Supply Voltage (Vpp) | 2.0 V to 5.5 V |
|---|---|
| Battery Supply Voltage (VBaT) | 1.8 V to 5.5 V |
| Battery Supply Current (IBAT) | 400 nA |
| Low Power Mode Current | ≈1.4 µA |
| Crystal Frequency | 32.768 kHz |
| SRAM Size | 8 bytes |
The device operates from 2.0 V to 5.5 V on the Vpp supply.
In battery backup mode the device draws about 400 nA.
A 32.768 kHz crystal is required for the oscillator.