NXP Semiconductors PCF85053A CMOS Real-Time Clock (RTC)

NXP Semiconductors PCF85053A CMOS Real-Time Clock (RTC) is optimized for low power consumption and automatic switching to battery on primary power loss. The NXP Semiconductors PCF85053A features clock output, alert interrupt output, a 128-byte battery backed-up SRAM, and two I²C buses. Its clock output calibration-related registers set the PCF85053A apart from other RTCs, which allows for crystal capacitive load (CL) configuration and offset register setting.

Features

1.7V to 3.6V supply voltage
1.55V to 3.6V battery supply voltage
Provides year, month, day, weekday, hours, minutes, and seconds based on a 32.768kHz quartz crystal
Device addresses
- 1101 111 RTC
- 1010 111 SRAM
Two independent I²C with speed 400kHz max
- I²C clock timeout 35ms max
- Primary I²C bus
  - Read/write capability on RTC and SRAM registers
  - Active low ALRT (interrupt) output
- Second I²C bus
  - Read/write capability on RTC and SRAM registers enabled by primary I²C
I²C bus not active during battery switchover

Real-time clock and calendar
Align to MC146818B register definition for offset 0 to 09h
Supports both binary mode and BCD mode
Supports 24-hour and 12-hour mode
Support daylight saving mode
Interrupt flag support
RTC_CLR flag
Alarm flag
RTC fail flag
Oscillator fail flag
Battery-backed 128-byte SRAM
SRAM clear to ‘0’ by RTC_CLR Pin
Frequency adjustment via programmable offset register
Configurable oscillator circuit for a wide variety of quartzes like CL = 6pF, CL = 7pF, and CL = 12.5pF
-40°C to 85°C operating temperature range

Applications

Server and computer precision timekeeping
Network-powered and industrial electronics

Products with long automated unattended operation time
White goods

NXP Semiconductors PCF85053A CMOS Real-Time Clock (RTC)

Features

Applications

Block Diagram

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