PCF2127AT/1,512

Real Time Clock Overview

The PCF2127AT/1,512 is a CMOS Real Time Clock (RTC) and calendar IC featuring an integrated Temperature Compensated Crystal Oscillator (TCXO) and a 32.768 kHz quartz crystal. It provides high accuracy with typical precision of ±3 ppm from -15°C to +60°C and low power consumption, drawing a typical current of 0.65 µA at VDD = 3.0 V and Tamb = 25°C. The device includes 512 bytes of general-purpose static RAM, selectable I²C or SPI interfaces, and a backup battery switch-over circuit. It supports programmable alarms, watchdog timers, countdown timers, and timestamp functions with interrupt capabilities.

Real Time Clock Feature Summary

• Integrated TCXO with 32.768 kHz quartz crystal for high accuracy (±3 ppm typical)
• Selectable 400 kHz Fast-mode I²C bus or 3-line SPI bus interface
• 512 bytes of battery-backed general-purpose static RAM
• Programmable watchdog timer, countdown timer, and alarm function with interrupts

Real Time Clock Applications

• Electronic metering for electricity, water, and gas
• Precision timekeeping and access to accurate time of day
• GPS equipment to reduce time to first fix
• Products requiring long automated unattended operation

Real Time Clock Procurement Notes

Verify the ordering suffix /1,512 corresponds to IC revision 1. Note that this part is not recommended for new designs; the replacement part is PCF2127AT/2. Confirm package type is SO20 (SOT163-1). Check delivery form options such as tube dry pack or tape and reel.

Real Time Clock Selection Notes

Select this component when high timing accuracy within industrial temperature ranges is required without external crystals. Ensure the system voltage falls within the 1.2 V to 4.2 V operating range. Verify interface compatibility with either I²C or SPI modes via the IFS pin configuration.

Real Time Clock Part Context

The PCF2127AT/1,512 belongs to the PCF2127 family of RTCs. It is distinguished by its integrated TCXO and quartz crystal, eliminating the need for external components typically required for frequency stability. This integration simplifies PCB layout and improves reliability compared to discrete oscillator solutions.

Real Time Clock Replacement Considerations

The datasheet explicitly states that the PCF2127AT/1 is not to be used for new designs. The confirmed replacement part number is PCF2127AT/2.