PCF85063ATT/AJ

The PCF85063ATT/AJ from NXP is an ultra-low-power I2C real-time clock and calendar in an 8-XSON (2.0×1.5mm) package. It draws only 110nA typical backup current on VBAT, extending coin-cell battery life to over 10 years. The device provides seconds through century calendar with leap year compensation. Features include a programmable alarm, countdown timer, and event timestamp that records the time when VDD drops below a threshold. The automatic battery switchover seamlessly transitions between VDD and VBAT supplies. The AJ grade supports -40C to +85C operation.

The PCF85063ATT/AJ integrates a 32.768kHz crystal oscillator with a divider chain that generates 1Hz timekeeping pulses. These pulses increment the seconds register, which cascades to minutes, hours, days, weekdays, months, and years with automatic leap year correction. Time data is accessed via I2C at addresses 0x51. The alarm function compares alarm registers with current time and asserts the interrupt pin on match. The countdown timer decrements from a programmed value and generates an interrupt on underflow. The timestamp function captures the current time when VDD falls below a threshold, allowing reconstruction of power-failure timing. Battery switchover automatically connects VBAT when VDD drops below the threshold.

• Portable and battery-powered timekeeping (coin cell backup)
• Smart meter power-failure timestamp logging
• Industrial PLC and controller real-time scheduling
• Medical wearable device time and date
• Automotive telematics and event logging