PCF8802AUG中文资料Smartcard RTC; ultra low power oscillator with integrated counter for initiating one time password generation数据手册恩XP规格书

描述 Description

The PCF8802 is a CMOS integrated circuit for battery operation, typically supplied bybutton cells or flexible polymer batteries. Incorporated is a 32.768 kHz quartz crystaloscillator circuit including the two load capacitors. The circuit is optimized for a quartz with6 pF load capacitance specification. Higher values can also be used with the addition ofexternal load capacitors.
The main function of the oscillator is to generate a 1⁄32 Hz clock signal which is used toincrement a 24 bit binary counter. The counter can be read over the serial interface andcan also be set to any desired value. Control over the divider chain also allows foraccurate starting of the counter. Incrementing of the counter value during read isprevented by freezing of the counter during access.
An interrupt signal is also available and is triggered coincident with the counter updating.This signal can be used as a wake-up for a microcontroller.

特性 Features

32.768 kHz quartz oscillator, amplitude regulated with excellent frequency stability andhigh immunity to leakage currents
Two integrated quartz crystal oscillator capacitors
Very low current consumption: typically 130 nA
Two-wire serial interface (I²C-bus)
Integrated 24-bit counter with auto increment every 32 seconds
Interrupt output for processor wake-up
Stop function for accurate time setting and current saving during shelf life
User test modes for accelerated application testing and development

应用 Application

One time password function generators
Ultra low-power time keeper circuit