PCF8563T/5,518: Comprehensive Analysis of Characteristics and Applications

The PCF8563T/5,518 is a high-performance, low-power CMOS real-time clock/calendar chip introduced by NXP Semiconductors, featuring an 8-pin SOIC package. It communicates with the host device via the I²C bus and offers timekeeping functions including seconds, minutes, hours, days, weeks, months, and years. This chip is suitable for various portable and embedded devices' time management requirements.

Features and Advantages

- Based on a 32.768kHz crystal oscillator, it provides year, month, day, weekday, hour, minute and second timing.

- Century flag

- Clock operating voltage: 1.0 - 5.5 V (room temperature)

- Low standby current; typical value is 0.25 μA (VDD = 3.0 V, Tamb = 25 °C)

- 400 kHz two-wire I2C bus interface (VDD = 1.8 - 5.5 V)

- Programmable clock output (32.768 kHz, 1.024 kHz, 32 Hz and 1 Hz)

- Alarm and timer functions

- Integrated crystal oscillator capacitor

- Internal power-on reset (POR)

- I2C bus slave address: read: A3h; write: A2h

- Open-drain interrupt pin

Application

◼ Mobile Phones

In smartphones and feature phones, the PCF8563T/5,518 serves as a real-time clock backup when the main system is powered down. Even when the primary battery is drained, the RTC chip can continue running using a backup battery. With its I²C interface, it integrates easily with main processors, and its ultra-low power consumption ensures minimal impact on battery life.

Use Cases:

Retain local time during shutdown

Trigger alarms or calendar events

Timestamp power failure or reboot events

◼ Portable Instruments

In portable measurement instruments (e.g., environmental sensors, handheld data loggers), the PCF8563T/5,518 acts as an independent timekeeper for data logging and event tracking. Its programmable alarms and timers support low-power system wake-up and scheduled tasks.

Use Cases:

Scheduled power-on/off for data logging

Timestamp measurement events

Timer-based wake-up for energy efficiency

◼ Electronic Metering

In smart meters (electricity, gas, water), accurate timekeeping is essential for time-based billing and logging. The PCF8563T/5,518 ensures continuous operation even during power outages. Its wide supply voltage range (1.0V–5.5V) suits variable power environments.

Use Cases:

Time-of-use (TOU) billing

Timestamp and synchronization before data upload

Real-time retention during power loss

◼ Battery-Powered Devices

For battery-operated devices like remote controls, wireless modules, and sensor nodes, PCF8563T/5,518 provides ultra-low power RTC capabilities, extending battery life. With typical current around 250nA, it's ideal for devices in deep sleep modes.

Use Cases:

Periodic wake-up for tasks

Alarm/alert system

Battery time tracking and log history

Product Packaging

Model: PCF8563T/5,518

Package Type: SOIC-8 (3.9mm wide body)

Operating Temperature Range: -40°C to +85°C

Complies with RoHS, lead-free environmentally friendly design

Conclusion

The PCF8563T/5,518 offers extremely high cost-effectiveness and availability, and is widely used globally in IoT terminals, industrial control, and wearable products. Its ultra-low power consumption feature and flexible timing mechanism make it the preferred choice for most low-power devices' RTCs.