描述 Description

The PT7C43390 is a CMOS I2C-bus real-time clock IC,which operates with the very low current consumptionand in the wide range of operation voltage. Theoperation voltage is 1.35 V to 5.5 V so that the RTC canbe used for various power supplies from main supply tobackup battery. In the system which operates with abackup battery, the included free registers can be used asthe function for user’s backup memory. Users alwayscan take back the information in the registers which isstored before power-off the main power supply, after thevoltage is restored.The IC has the function to correct advance / delay of theclock data speed, in the wide range, which is caused bythe oscillation circuit’s frequency deviation. Correctingaccording to the temperature change by combining thisfunction and a temperature sensor, it is possible to makea high precise clock function which is not affected bythe ambient temperature.

特性 Features

Low current consumption: 0.3μA typ. (VDD=3.0V, TA = 25°C)
Wide operating voltage range: 1.35 to 5.5 V
Minimum time keeping operation voltage: 1.25 V
Built-in clock adjustment function
Built-in free user register
2-wire (I2C-bus) CPU interface
Built-in alarm interrupter
Built-in flag generator at power down or power on
Auto calendar up to the year 2099, automatic leap year calculation function
Built-in constant voltage circuit
Built-in 32 kHz crystal oscillator circuit
Package: SOIC-8L, TSSOP-8L, and TDFN2x3-8L