PCF2123BS/1,518

Real Time Clock Overview

The PCF2123BS/1,518 is a CMOS Real-Time Clock (RTC) and calendar optimized for low power applications. It provides year, month, day, weekday, hours, minutes, and seconds based on a 32.768 kHz quartz crystal. The device features a Serial Peripheral Interface (SPI-bus) with a maximum data rate of 6.25 Mbit/s. Key electrical parameters include a clock operating voltage range of 1.1 V to 5.5 V and a typical backup current of 100 nA at VDD = 2.0 V and Tamb = 25 °C. It includes an offset register for frequency adjustment, watchdog functionality, and programmable timer and alarm functions with interrupt capability.

Real Time Clock Feature Summary

• Real-time clock/calendar providing timekeeping from seconds to years using a 32.768 kHz quartz crystal
• Ultra-low power consumption with typical backup current of 100 nA at 2.0 V
• High-speed SPI interface supporting up to 6.25 Mbit/s data rate
• Integrated oscillator load capacitors for CL = 7 pF and programmable offset register for calibration

Real Time Clock Applications

• Time keeping applications
• Battery powered devices
• Metering equipment
• High duration timers
• Low standby power applications

Real Time Clock Procurement Notes

Verify the ordering suffix ,518 corresponds to tape and reel delivery in 13-inch dry pack format as specified in the NXP datasheet. Confirm package type HVQFN16 matches the design requirements. Check for RoHS compliance status via official documentation. Ensure supply availability aligns with project timelines given potential lifecycle changes.

Real Time Clock Selection Notes

Select this component when SPI communication is preferred over I2C interfaces. Ensure the system voltage falls within the 1.1 V to 5.5 V operating range. Consider the HVQFN16 package dimensions (3 x 3 x 0.85 mm) for PCB layout constraints. Verify that the required interrupt pins (INT, CLKOUT) are available on the host microcontroller.

Real Time Clock Part Context

The PCF2123 series includes variants such as PCF2123TS (TSSOP14) and PCF2123U (bare die). The BS variant specifically utilizes the HVQFN16 package. All variants share the same core RTC functionality but differ in physical packaging and mounting methods. The datasheet revision 6 indicates updates to functional descriptions and timing characteristics compared to earlier releases.

Real Time Clock Replacement Considerations

Direct replacements must support SPI interface and similar voltage ranges. PCF2123TS/1 offers identical functionality in TSSOP14 package. Other NXP RTCs like PCF85063 use I2C and require interface adaptation. Verify pin compatibility and register mapping before substituting.