AB1805-T3

Overview

The Abracon AB1805-T3 is a Real-Time Clock (RTC) IC featuring an I2C interface and 256 bytes of general-purpose RAM. It operates within a supply voltage range of 1.7V to 3.6V, with timekeeping current consumption ranging from 0.17µA to 0.22µA at 1.8V to 3V. The device supports HH:MM:SS:hh time format and YY-MM-DD-dd date format. Encased in a 16-VFQFN Exposed Pad package (3x3 mm), it functions across an operating temperature range of -40°C to 85°C.

Feature Summary

• Integrated power management including ~1 Ω power switch for off-chip components and system sleep manager
• Advanced timekeeping with programmable alarms on all counters and automatic leap year calculation
• Ultra-low power modes: 14 nA with RC oscillator, 22 nA with autocalibration, and 55 nA with crystal oscillator
• Supercapacitor trickle charger with programmable charging current and automatic switchover to VBAT

Applications

• Smart cards
• Wireless sensors and tags
• Medical electronics
• Utility meters
• Data loggers

Procurement Notes

Verify the specific suffix '-T3' against official documentation to confirm packaging details such as Tape & Reel or Cut Tape specifications. Ensure the selected variant matches the required I2C interface configuration and that the 16-VFQFN thermal pad connection requirements are met during assembly.

Selection Notes

Select the AB1805-T3 when an I2C interface is required alongside advanced power management features like the integrated power switch and sleep FSM. Consider the AB1815 if SPI communication is preferred instead. Evaluate the need for autocalibration mode to achieve ±2 ppm accuracy versus standard RC oscillator operation for lower current draw.

Part Context

The AB1805 belongs to the AB18X5 family, which utilizes Ambiq Micro's proprietary SPOT (Subthreshold Power Optimized Technology) CMOS platform. This family provides ultra-low power RTC functionality combined with sophisticated power management capabilities, distinguishing it from baseline RTCs by integrating host processor wake/sleep control and backup power switching.

Replacement Considerations

The AB0805 is software and pin compatible but lacks the advanced power management features found in the AB1805. Verify interface compatibility, as the AB0815 uses SPI instead of I2C.