PCF8523TK/1,118

Real Time Clock Overview

The PCF8523TK/1,118 is a CMOS Real-Time Clock (RTC) and calendar optimized for low power consumption. It provides year, month, day, weekday, hours, minutes, and seconds based on a 32.768 kHz quartz crystal with resolution from seconds to years. The device operates at a clock voltage of 1.0 V to 5.5 V and features a typical backup current of 150 nA at VDD = 3.0 V and Tamb = 25 °C. Data transfers occur via a 2-line bidirectional 1 MHz Fast-mode Plus (Fm+) I2C interface. Key specifications include selectable integrated oscillator load capacitors (7 pF or 12.5 pF), an offset register for frequency adjustment, and battery switch-over circuitry.

Real Time Clock Feature Summary

• I2C Interface: 2-line bidirectional 1 MHz Fast-mode Plus (Fm+) interface with read address D1h and write address D0h.
• Power Management: Low backup current of 150 nA (typical at 3.0 V); includes battery switch-over and low detection functions.
• Clock Accuracy: Programmable offset register for fine-tuning; selectable internal oscillator load capacitors (7 pF or 12.5 pF).
• Interrupts & Alarms: Freely programmable timer and alarm functions with interrupt capability on open-drain pins.

Real Time Clock Applications

• Time keeping applications
• Battery powered devices
• Metering

Real Time Clock Procurement Notes

Verify the package type HVSON8 (SOT909-1) matches the design requirements. Confirm the ordering suffix ,118 indicates tape and reel delivery in a 13-inch format. Check the product status as the component may be discontinued or subject to last-time buy notices. Ensure the I2C slave addresses (Read D1h, Write D0h) are compatible with the system bus configuration.

Real Time Clock Selection Notes

Select this part for applications requiring ultra-low power standby currents and precise timekeeping without external temperature compensation. The HVSON8 package is suitable for space-constrained designs. Verify that the host microcontroller supports I2C Fast-mode Plus speeds up to 1 MHz. Consider the available interrupt lines if multiple wake-up sources are required for the system.

Real Time Clock Part Context

The PCF8523TK/1,118 is the HVSON8 package variant of the PCF8523 RTC family. The 'TK' designation identifies the plastic thermal enhanced very thin small outline package with no leads and 8 terminals. The '/1,118' suffix specifies the standard tape and reel packaging format. This component belongs to NXP's portfolio of low-power real-time clocks designed for battery-operated consumer and industrial electronics.

Real Time Clock Replacement Considerations

Public confirmed substitute part numbers are not provided in the source material. Designers should consult NXP documentation for cross-reference options or evaluate other RTCs within the same family, such as the PCF8523T (SO8) or PCF8523TS (TSSOP14), ensuring pin compatibility and electrical specifications match.