PCF2129AT/1,518

Real Time Clock Overview

The PCF2129AT/1,518 is a CMOS Real Time Clock (RTC) and calendar IC from NXP Semiconductors. It features an integrated Temperature Compensated Crystal Oscillator (TCXO) with a 32.768 kHz quartz crystal, optimized for high accuracy and low power consumption. The device supports selectable I²C or SPI interfaces and operates within a voltage range of 1.8 V to 4.2 V. It provides complete calendar functions including leap year correction and timestamp capabilities. The component is housed in a 20-lead SO package (SOT163-1) and is designed for industrial applications with an operating temperature range of -40 °C to +85 °C.

Real Time Clock Feature Summary

• Integrated TCXO with ±3 ppm typical accuracy (-15 °C to +60 °C)
• Selectable I²C (400 kHz Fast-mode) or SPI (up to 6.5 Mbit/s) interface
• Battery backup switch-over circuitry with battery low detection
• Programmable watchdog timer, alarm function, and interrupt outputs

Real Time Clock Applications

• Electronic metering for electricity, water, and gas
• GPS equipment to reduce time to first fix
• Products requiring long automated unattended operation

Real Time Clock Procurement Notes

Verify the ordering suffix /1,518 against official documentation, as standard reel quantities are typically listed as /2,518. Confirm package type SOT163-1 matches design requirements. Ensure interface selection via IFS pin aligns with system architecture before integration.

Real Time Clock Selection Notes

Select this model for applications demanding high timing precision without external crystals. The integrated TCXO eliminates layout sensitivity issues associated with discrete components. Verify that the 1.8 V to 4.2 V supply range covers both main and backup power scenarios.

Real Time Clock Part Context

This part belongs to the PCF2129 series, which includes variants like PCF2129T (SO16 package). The AT variant specifically denotes the 20-lead SO package configuration. It is distinct from automotive-qualified versions such as the PCA2129.

Real Time Clock Replacement Considerations

PCF2129T/2,518 offers similar functionality but uses an SO16 package. PCA2129 is an automotive-grade equivalent with AEC-Q100 qualification. Check pin compatibility and register mapping when substituting.