NXP Semiconductors PCF8564AU/5GB/1,01

Overview

PCF8564AU/5GB/1,01 from NXP Semiconductors is a CMOS real-time clock and calendar IC with I²C interface, 32.768 kHz crystal oscillator, programmable clock output (32.768 kHz / 1.024 kHz / 32 Hz / 1 Hz), interrupt output, and voltage low detector. It operates from 1.0 V to 5.5 V and draws only 250 nA typical backup current at 3.0 V - enabling long-term timekeeping in battery-powered portable instruments and electronic metering systems.

For engineers reviewing the PCF8564AU/5GB/1,01 datasheet, PCF8564AU/5GB/1,01 pinout, PCF8564AU/5GB/1,01 application, or PCF8564AU/5GB/1,01 equivalent, this device delivers BCD-coded time/date registers (seconds through years), alarm and 8-bit countdown timer functions, auto-incrementing I²C address register, and integrated oscillator capacitors - all in a bare-die format optimized for wafer-level integration.

Technical Context

The PCF8564AU/5GB/1,01 implements a 32.768 kHz crystal-based timing core with on-chip oscillator and dual-stage prescaler chain (F0–F14) to generate 1 Hz for RTC counting. Its I²C interface supports 400 kbit/s operation across 1.8 V–5.5 V, with slave addresses A2h (write) and A3h (read).

Time and alarm registers (02h–0Ch) are BCD-encoded; the 8-bit timer (0Fh) uses selectable source clocks (4.096 kHz, 64 Hz, 1 Hz, or 1/60 Hz); CLKOUT is a push-pull output enabled via CLKOE pin and controlled by FD[1:0] bits in register 0Dh. The STOP bit halts RTC counting while preserving CLKOUT at 32.768 kHz.

Key Specifications

Pinout & Package

Bare die (unsawn wafer) with 9 bonding pads; substrate (rear side) connected to VSS potential per NXP mechanical specification.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar real-time clock applications.

Compared with PCF8564AU/5GB/1,01, the PCF8563T/5,118 offers identical functionality in a standard package but requires external capacitors, while the MCP7940M-I/SN adds EEPROM and SRAM at the cost of higher current and no CLKOUT programmability - making PCF8564AU/5GB/1,01 optimal for ultra-low-power wafer-level designs needing flexible clock outputs.

Availability

PCF8564AU/5GB/1,01 is available at Aetrix Electronics and suitable for electronic metering, portable medical devices, industrial data loggers, and smart home sensors requiring stable component supply across extended production lifecycles.

Supply support for PCF8564AU/5GB/1,01 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

NXP Semiconductors is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and IoT applications.

The PCF8564A product line was designed specifically for ultra-low-power, battery-backed real-time clock applications where long-term accuracy, minimal standby current, and wafer-level integration are critical - targeting metering, portable instrumentation, and energy-harvesting systems.

FAQ

What is the primary function of the PCF8564AU/5GB/1,01?

The PCF8564AU/5GB/1,01 is a real-time clock and calendar IC that maintains accurate time and date information using an internal 32.768 kHz oscillator circuit. It provides BCD-coded registers for seconds, minutes, hours, days, weekdays, months, and years, along with alarm, timer, and programmable clock output functions - all operating down to 1.0 V with 250 nA typical backup current. This makes PCF8564AU/5GB/1,01 ideal for long-life battery-powered applications.

Does the PCF8564AU/5GB/1,01 require external load capacitors for the crystal?

No, the PCF8564AU/5GB/1,01 integrates two oscillator load capacitors internally, eliminating the need for external 12.5 pF capacitors typically required with 32.768 kHz tuning-fork crystals. This reduces bill-of-materials count and PCB footprint - a key advantage for space-constrained and wafer-level packaging implementations of PCF8564AU/5GB/1,01.

How does the voltage low (VL) detection work in the PCF8564AU/5GB/1,01?

The PCF8564AU/5GB/1,01 includes an on-chip voltage low detector that monitors VDD. When supply voltage drops below the threshold, the VL (Voltage Low) flag in the Seconds register (bit 7, address 02h) is set to 1, indicating time integrity may be compromised. The VL flag remains set until cleared by firmware write and serves as a reliable indicator for discarding potentially corrupted time data after brownout events - a critical safeguard in PCF8564AU/5GB/1,01 deployments.

Can the PCF8564AU/5GB/1,01 generate multiple clock frequencies simultaneously?

No, the PCF8564AU/5GB/1,01 provides only one CLKOUT signal, programmable to 32.768 kHz, 1.024 kHz, 32 Hz, or 1 Hz via FD[1:0] bits in register 0Dh. The selected frequency is output on the CLKOUT pin when CLKOE is high; otherwise, CLKOUT is driven low. There is no hardware support for concurrent multiple frequencies - PCF8564AU/5GB/1,01 prioritizes ultra-low power over multi-output flexibility.

What is the I²C slave address used to communicate with the PCF8564AU/5GB/1,01?

The PCF8564AU/5GB/1,01 uses fixed I²C slave addresses: 0xA2 (10100010b) for write operations and 0xA3 (10100011b) for read operations. These addresses are hardwired and not configurable. Communication follows standard I²C protocol with 7-bit addressing, supporting up to 400 kbit/s bus speed across 1.8 V–5.5 V VDD - ensuring compatibility with most microcontrollers interfacing with PCF8564AU/5GB/1,01.