Real-Time Clocks

Delivering high accuracy and low power consumption

NXP Real-Time Clocks (chips)

NXP's broad assortment of tiny, full-featured, real-time clocks delivers high accuracy and low power consumption to a variety of end applications. From battery management and alarm to time-stamp and tamper detect functionality—our RTCs offer a wide range of features for your system. Automotive compliant AEC-Q100 devices are also available.

  • Ultra-Low-Power RTCs provide the low power consumption that enables long battery life with regard to real-time clock functionality. Energy-efficient devices are available with I2C or SPI bus interfaces.
  • Temperature Compensated with Integrated Crystal CMOS RTCs are optimized for very high accuracy and low power consumption for industrial applications. The devices sense temperature and make internal adjustments to ensure accurate timekeeping over the temperature range. Available with pin-selectable I2C bus or SPI bus.
  • AEC-Q100 Qualified RTCs are designed for highest reliability and lowest power consumption and are available with I2C or SPI bus interfaces. They have an extended operating temperature range of up to 125° C and AEC-Q100 automotive-compliant qualification.

 

The PCF85x63 family of RTCs are all optimized for extremely low power consumption (<300nA), making them a great fit in portable sensors and IoT applications. The low quiescent current makes these RTCs a great fit alongside microcontrollers and processors, which are often an order of magnitude higher in terms of shutdown (or deep sleep) current. By keeping only the external RTC alive and putting the digital IC in full shutdown, the average power can be greatly reduced, allowing smaller batteries, longer system runtime and additional system features at the same power budget. Operating from a 1.8V to 5.5V supply voltage, these RTCs interface with a wide range of batteries and power supply rails.

 

PCF8563

CMOS1 Real-Time Clock (RTC) and calendar optimized for low power consumption. A programmable clock output, interrupt output, and voltage-low detector are also provided. All addresses and data are transferred serially via a two-line bidirectional I 2C-bus. Maximum bus speed is 400 kbit/s. The register address is incremented automatically after each written or read data byte.

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PCF85063

CMOS1 Real-Time Clock (RTC) and calendar optimized for low power consumption. An offset register allows fine-tuning of the clock. All addresses and data are transferred serially via the two-line bidirectional I2C-bus. Maximum bus speed is 400 kbit/s. The register address is incremented automatically after each written or read data byte.

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PCF85263

CMOS1 Real-Time Clock (RTC) and calendar optimized for low power consumption and with automatic switching to battery on main power loss. The RTC can also be configured as a stop-watch (elapsed time counter). Three time log registers triggered from battery switch-over as well as input driven events. Featuring clock output and two independent interrupt signals, two alarms, I2C interface and quartz crystal calibration.

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NXP's automotive real-time clocks provide the highest reliability and lowest power consumption. These devices feature either I2C or SPI bus interfaces. These solutions support a range of automotive applications (instrument cluster, tachographs, black boxes for electronic road pricing, battery management units, car radios). They provide year, month, day, weekday, hours, minutes and second information and feature programmable alarm and timer functions with interrupt capability. They also offer AEC-Q100 automotive compliant qualification.

Features:

  • Extended operating temperature range from -40ºC to +125ºC
  • Extended operating temperature range to +125 ºC to withstand harshest conditions
  • Wide power supply voltage range from 1.6V/1.8V to 5.5V
  • Automotive AEC-Q100 compliant qualification for highest reliability and robustness
  • Low power consumption (0.55 / 0.65 μA at VDD = 3.0 V and Tamb = 25 °C)
  • Low power consumption to enable power critical applications
  • I2C or SPI interface
  • Programmable alarm and timer functions with interrupt capability
  • One integrated oscillator capacitor
  • Programmable clock output to drive peripheral devices

     

Target Applications:

  • Instrument clusters
  • Tachographs
  • Black boxes for electronic road pricing
  • Battery management units
  • Car radios

 

PCA21125T

CMOS1 Real-Time Clock (RTC) and calendar optimized for low-power consumption and an operating temperature up to 125 °C. Data is transferred via a Serial Peripheral Interface (SPI-bus) with a maximum data rate of 6.0 Mbit/s. Alarm and timer functions are also available with the possibility to generate a wake-up signal on the interrupt pin.

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PCA2129T

CMOS1 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 PCA2129 has a selectable I2C-bus or SPI-bus, a backup battery switch-over circuit, a programmable watchdog function, a timestamp function, and many other features.

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PCA85063ATT

CMOS1 Real-Time Clock (RTC) and calendar optimized for low power consumption. An offset register allows fine-tuning of the clock. All addresses and data are transferred serially via the two-line bidirectional I2C-bus. Maximum data rate is 400 kbit/s. The register address is incremented automatically after each written or read data byte.

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RTC Selector Guide

RTC Portfolio PCF8563 PCF85063 PCF85263 PCF85363 PCF8523 PCF2123 PCF2127 PCF2129 PCA21125
Time and Clock Out
Alarm ✓ 2x ✓ 2x
Timer
Watch Dog Timer
Interface Watch Dog                
Interrupt ✓ 2x ✓ 2x ✓ 2x
Stop Watch              
Time Stamp     ✓ 3x ✓ 3x      
Time Stamp/Tamper Input          
Battery Backup          
Turning Register    
Temperature Compensation              
Factory Calibration              
Quartz Crystal              
RAM Integrated              
High Temperature PCA8565 PCA85063A            
AEC-Q100 Automotive PCA8565 PCA85063A           PCA2129
Interface

Product Brief

NXP RTC / PCF85263

Energy-efficient, autonomous timing circuit featuring time stamp, battery back-up, two alarms, and resolution up to 1/100s.

Product Brief

Real-time clocks for automotive applications

In automotive applications, exposure to extreme temperatures presents a series challenge to accurate timing. NXP has the solution.