Accurate RTC with 512 B RAM and Battery Backup – Selectable I²C-Bus Or SPI

PCF2127

Click over video to play

The PCF2127 is a CMOS Real Time Clock (RTC) and calendar with an integrated Temperature Compensated Crystal (Xtal) Oscillator (TCXO) and a 32.768 kHz quartz crystal optimized for very high accuracy and very low power consumption. The PCF2127 has 512 bytes of general-purpose static RAM, a selectable I2C-bus or SPI-bus, a backup battery switch-over circuit, a programmable watchdog function, a timestamp function, and many other features.

Product Details

Select a section:

Features

  • UL Recognized Component
  • Operating temperature range from -40 °C to +85 °C
  • Temperature Compensated Crystal Oscillator (TCXO) with integrated capacitors
  • Typical accuracy:
    • PCF2127AT: ±3 ppm from -15 °C to +60 °C
    • PCF2127T: ±3 ppm from -30 °C to +80 °C
  • Integration of a 32.768 kHz quartz crystal and oscillator in the same package
  • Provides year, month, day, weekday, hours, minutes, seconds, and leap year correction
  • 512 bytes of general-purpose static RAM
  • Timestamp function:
    • with interrupt capability
    • detection of two different events on one multilevel input pin (for example, for tamper detection)
  • Two line bidirectional 400 kHz Fast-mode I²C-bus interface
  • 3 line SPI-bus with separate data input and output (maximum speed 6.5 Mbit/s)
  • Battery backup input pin and switch-over circuitry
  • Battery backed output voltage
  • Battery low detection function
  • Extra power fail detection function with input and output pins
  • Power-On Reset Override (PORO)
  • Oscillator stop detection function
  • Interrupt output (open-drain)
  • Programmable 1 second or 1 minute interrupt
  • Programmable watchdog timer with interrupt
  • Programmable alarm function with interrupt capability
  • Programmable square wave output pin
  • Programmable countdown timer with interrupt
  • Clock operating voltage: 1.8 V to 4.2 V
  • Low supply current: typical 0.70 μA at VDD = 3.3 V

Target Applications

  • Electronic metering for electricity, water, and gas
  • Precision timekeeping
  • Access to accurate time of the day
  • GPS equipment to reduce time to first fix
  • Applications that require an accurate process timing
  • Products with long automated unattended operation time

Documentation

Quick reference to our documentation types.

Filters

1-5 of 13 documents

Show All

Design Resources

Select a section:

Hardware

Filters

1 hardware offering

Engineering Services

1 engineering service

To find a complete list of our partners that support this product, please see our Partner Marketplace.

Support

What do you need help with?

Search