Features and key benefits Accurate timekeeping through year 2099: maintains seconds, minutes, hours, day of week, day, month and year, with automatic leap-year adjustment. Low-power backup capability: separate main and emergency power inputs preserve time and RAM during power loss. Compact, flexible packaging: available in 8-pin DIP or optional 8-pin SOIC (surface-mount) housings to suit through-hole or SMD assembly. Minimal MCU pin usage: simple 3-wire serial I/O reduces required I/O pins while providing reliable data transfer. Wide voltage range and TTL compatibility: operates from 2.0 V to 5.5 V and is compatible with TTL systems when VCC = 5 V. Industrial temperature range: specified for operation from -40°C to +85°C for stable performance in demanding environments. Low standby current: operating current at 2.0 V is less than 300 nA, conserving battery backup power. On-chip user RAM: 31 × 8-bit temporary data storage bytes for small data buffers or user variables. Flexible read/write modes: supports single-byte and multi-byte (character-group) transmission methods for clock and RAM access. Technical highlights Timekeeping: seconds, minutes, hours, day of week, date, month, year (valid through 2099), automatic leap-year correction. Memory: 31 bytes of 8-bit temporary RAM for user data storage. Interface: simple 3-wire serial interface that minimizes pin count and simplifies PCB routing. Power: dual power pins for main power supply and emergency (backup) power supply to maintain time and RAM during outages. Voltage: operating range 2.0 V to 5.5 V; TTL compatible at VCC = 5 V. Current: < 300 nA standby current at 2.0 V. Packaging: 8-pin DIP or optional 8-pin SOIC (surface-mount). Temperature: -40°C to +85°C industrial range. Data transfer: supports single-byte and multi-byte (block/character-group) transmission for reading/writing clock and RAM. Why customers choose this product Saves system resources: the 3-wire serial interface and small package reduce PCB space and free up MCU pins for other functions. Robust timekeeping without host intervention: on-chip calendar logic and leap-year handling remove the need for software time correction. Reliable battery-backed operation: dual power inputs and ultra-low standby current preserve time and data during power loss, extending backup battery life. Broad compatibility: wide voltage range and TTL compatibility allow use across 3.3 V and 5 V systems. Suitable for harsh environments: industrial temperature rating supports use in outdoor or industrial equipment. Typical applications Data loggers and meters: maintain accurate timestamps and small user buffers while consuming minimal backup power. Embedded controllers and IoT nodes: provide calendar/time services with minimal MCU pin usage and compact packaging for space-constrained designs. Industrial automation and remote monitoring: reliable timekeeping across wide temperature ranges and during power interruptions for event stamping and scheduling. Usage notes Use the specified 3-wire serial protocol for clock and RAM read/write operations; both single-byte and multi-byte methods are supported. Connect main and emergency power supplies to the appropriate power pins to ensure uninterrupted timekeeping and RAM retention. Ensure VCC level compatibility when interfacing with TTL-level systems (VCC = 5 V for TTL compatibility). Specifications (summary) Timekeeping: to year 2099, leap-year adjust RAM: 31 × 8-bit bytes Interface: 3-wire serial I/O Voltage: 2.0 V to 5.5 V (TTL compatible at VCC = 5 V) Standby current: < 300 nA at 2.0 V Temperature: -40°C to +85°C Packages: 8-pin DIP or optional 8-pin SOIC (surface mount) Power: dual power inputs for main and emergency supplies Data transfer: single-byte and multi-byte (character group) methods This description reflects the device specifications and functions as provided.