ST offers a wide portfolio of real-time clock (RTC) ICs with parallel or serial interface, including ultra-low-power devices packaged in standard SMD SOX18 and SOX28 with embedded ±5ppm 32kHz factory-calibrated Crystal.

Our devices offer many value-added features such as supervisory functions that include alarm, battery switchover, and reset as well as special features with time stamp and anti-tamper for secure applications.

Applications

Real-time clock (RTC) ICs can be used on a broad range of applications.

Home and Professional Appliances

GNSS/GPS

Bridge and Gateway

Product types

Battery and Crystal

These devices are detachable lithium power sources with embedded 32-kHz crystal housed in a special top called SNAPHAT®. They are compatible with ST’s Serial RTC and nonvolatile TIMEKEEPER® surface-mount in SOIC (MH) package.

Find products

RTC - Parallel Interface (Timekeepers)

ST's parallel real-time clock ICs, also called Timekeepers, combine a SRAM with up to 256 Kbytes of memory and a byte-wide interface along with a quartz-based very-low-power oscillator with a clock/calendar circuit to provide real-time data.
Advanced RTC ICs include additional features such as programmable alarms, watchdog timers, system reset outputs and battery-low warning flags.

Find products

RTC - Serial Interface

ST's serial real-time clocks range from ultra-low power devices for portable applications to high-accuracy parts with analog calibration up to factory-calibrated RTC modules with an embedded crystal.

Find products

Benefits

Along with ST’s serial and parallel RTC portfolio, ST's unique SNAPHAT® devices have a special removable/replaceable top that contains a lithium coin-cell battery and a 32-kHz crystal designed to be "snapped on" after the surface mount process. It solves the reflow compatibility of the lithium batteries and provides a solution compatible with all ST's real-time clocks in surface-mount SOH-28 and SOH-44 packages.

All ST RTCs are Underwriters Laboratories® (UL) recognized, see application note AN1011; "Battery technology used in NVRAM and real-time clock (RTC) products".

• Integrated switchover
• Long time retention with capacitor backup
• Embedded crystal

• Low standby current
• Analog and digital calibration

• Analog and digital calibration
• Embedded crystal with factory calibration
• NVRAM for retention of configuration data
• Tamper detection
• Replaceable battery and crystal

Real-time clock (RTC) design support

• Battery life calculator evaluates the battery capacity consumption and lifetime of ST's real-time clock ICs
• Clock calibration calculator demonstrates the digital calibration feature of RTC ICs

See also our summary of development hints in application noteAN3060;"Application guide for serial real-time clocks (RTCs)".