The PCF2127 is a CMOS Real Time Clock (RTC) and calendar with an integratedTemperature Compensated Crystal (Xtal) Oscillator (TCXO) and a 32.768 kHz quartzcrystal optimized for very high accuracy and very low power consumption. The PCF2127has 512 bytes of general-purpose static RAM, a selectable I2C-bus or SPI-bus, a backupbattery switch-over circuit, a programmable watchdog function, a timestamp function, andmany other features.

• UL Recognized Component
• Operating temperature range from -40 °C to +85 °C
• Temperature Compensated Crystal Oscillator (TCXO) with integrated capacitors
• Typical accuracy:
  • PCF2127AT: ±3 ppm from -15 °C to +60 °C
  • PCF2127T: ±3 ppm from -30 °C to +80 °C
• Integration of a 32.768 kHz quartz crystal and oscillator in the same package
• Provides year, month, day, weekday, hours, minutes, seconds, and leap yearcorrection
• 512 bytes of general-purpose static RAM
• Timestamp function:
  • with interrupt capability
  • detection of two different events on one multilevel input pin (for example, for tamperdetection)
• Two line bidirectional 400 kHz Fast-mode I2C-bus interface
• 3 line SPI-bus with separate data input and output (maximum speed 6.5 Mbit/s)
• Battery backup input pin and switch-over circuitry
• Battery backed output voltage
• Battery low detection function
• Extra power fail detection function with input and output pins
• Power-On Reset Override (PORO)
• Oscillator stop detection function
• Interrupt output (open-drain)
• Programmable 1 second or 1 minute interrupt
• Programmable watchdog timer with interrupt
• Programmable alarm function with interrupt capability
• Programmable square wave output pin
• Programmable countdown timer with interrupt
• Clock operating voltage: 1.8 V to 4.2 V
• Low supply current: typical 0.70 μA at VDD = 3.3 V

• Electronic metering for electricity, water, and gas
• Precision timekeeping
• Access to accurate time of the day
• GPS equipment to reduce time to first fix
• Applications that require an accurate process timing
• Products with long automated unattended operation time

• P5CN081HN - 安全双接口和接触式PKI智能卡控制器
• 74LVC3G14GT - 三路反相施密特触发器，带5 V容压输入
• PUMH15 - NPN/NPN配电阻晶体管；R1 = 4.7 kΩ，R2 = 4.7 kΩ
• BZX884-C10 - 稳压器二极管
• TDA18204HN - 有线电视预处理器和低功耗硅调谐器
• 74ABT16245B - 16位总线收发器（3态）
• SSL3252UK - 闪光LED驱动器
• BSS138BK - 60 V，360 mA N沟道Trench MOSFET
• NT2H1311G0DUF - NFC Forum类型2标签兼容型IC，集成144字节用户存储器
• PZU5.1B2 - 采用SOD323F封装的单倍齐纳二极管