NXP Semiconductors PCF85263ATT1/AZ

Overview

PCF85263ATT1/AZ from NXP Semiconductors is a CMOS real-time clock (RTC) and calendar IC with battery switch-over, dual alarms, three timestamp registers, and I²C-bus interface. It operates from 0.9 V to 5.5 V, draws just 0.28 µA at 3.0 V, and supports stop-watch mode up to 999 999 hours - used in battery-backed data loggers and network-powered devices.

For engineers reviewing the PCF85263ATT1/AZ datasheet, PCF85263ATT1/AZ pinout, PCF85263ATT1/AZ application, or PCF85263ATT1/AZ equivalent, key selection factors include TSSOP10 package compatibility, I²C timing at 400 kHz, battery-failover behavior, and timestamp-triggered interrupt generation on TS/INTB.

Technical Context

The PCF85263ATT1/AZ implements a fully autonomous RTC core with BCD-coded time/date registers (year–100th second), configurable 32.768 kHz oscillator (CL = 6/7/12.5 pF), and programmable clock output (32.768 kHz to 1 Hz). Its dual alarm system supports independent enable/disable per time field and outputs via open-drain INTA and push-pull INTB/CLK pins.

It features three timestamp registers triggered by battery switch-over or external TS input, plus a watchdog timer and offset calibration register for quartz frequency trimming. The device switches automatically to VBAT when VDD drops below threshold and maintains timekeeping down to 0.9 V supply.

Key Specifications

Pinout & Package

TSSOP10 package (SOT552-1), 3 mm body width, 0.5 mm pitch, lead-free and RoHS compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCF85263ATT1/AZ, PCF85263ATT/AJ sacrifices timestamp capability and clock output for reduced size, while PCF85263ATL/AX retains full functionality in a smaller DFN package but demands layout changes - making PCF85263ATT1/AZ optimal for drop-in TSSOP10 upgrades with legacy pin compatibility.

Availability

PCF85263ATT1/AZ is available at Aetrix Electronics and suitable for electronic metering, data loggers, and network-powered devices requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for PCF85263ATT1/AZ 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 specializing in secure connectivity solutions for automotive, industrial, and IoT applications.

The PCF85263A product line delivers ultra-low-power, feature-rich RTCs for applications demanding high-accuracy timekeeping, battery resilience, and intelligent event logging - designed specifically for metering, industrial sensing, and always-on edge devices.

FAQ

What is the primary function of the PCF85263ATT1/AZ?

The PCF85263ATT1/AZ is a real-time clock and calendar IC that maintains accurate time and date information with battery backup, dual alarms, three timestamp registers, and I²C interface. It serves as the timekeeping engine in systems requiring reliable, low-power, and event-aware timing - such as smart meters and data loggers. The PCF85263ATT1/AZ supports both RTC and stop-watch modes, enabling flexible elapsed-time measurement alongside calendar functions.

Does the PCF85263ATT1/AZ support automatic battery switchover?

Yes, the PCF85263ATT1/AZ includes an integrated battery switch-over circuit that automatically transfers power from VDD to VBAT when main supply voltage drops below the threshold. This ensures uninterrupted timekeeping during power failures. The PCF85263ATT1/AZ maintains full RTC functionality down to 0.9 V on VBAT and records timestamp events at the moment of switchover - a key capability confirmed in its datasheet Section 7.11 and Figure 1.

How many timestamp registers does the PCF85263ATT1/AZ provide, and what triggers them?

The PCF85263ATT1/AZ provides three dedicated timestamp registers (TSR1, TSR2, TSR3), each capturing full time/date data. They are triggered either by battery switch-over (power-loss event) or by a rising/falling edge on the TS pin. These registers are independently configurable via the TSR_mode register (address 23h), and their flags (TSR1F–TSR3F) are readable in the Flags register (2Bh). This functionality is explicitly documented in Sections 7.7 and Figure 1 of the PCF85263ATT1/AZ datasheet.

What package type is used for the PCF85263ATT1/AZ?

The PCF85263ATT1/AZ uses the TSSOP10 package (SOT552-1), a 10-lead plastic thin shrink small outline package with 3 mm body width and 0.5 mm pitch. Pin configuration matches Figure 5 in the datasheet: OSCI (1), OSCO (2), VBAT (3), TS/INTB (4), VSS (5), SDA (6), SCL (7), CLK (8), INTA/CLK (9), VDD (10). This package is RoHS-compliant and optimized for automated assembly in high-volume production.

Can the PCF85263ATT1/AZ generate a clock signal for other components?

Yes, the PCF85263ATT1/AZ provides a programmable clock output on the CLK pin (Pin 8), offering seven selectable frequencies: 32.768 kHz, 16.384 kHz, 8.192 kHz, 4.096 kHz, 2.048 kHz, 1.024 kHz, and 1 Hz. This output is push-pull and configurable via the CLKPM bits in the Pin_IO register (27h). It eliminates the need for external clock generators in systems requiring synchronized timing for ADC sampling, LED blinking, or communication interfaces - a feature confirmed in Section 2.2 and Table 2 of the datasheet.