BQ4845S-A4TR

Overview

The BQ4845S-A4TR is a parallel real-time clock (RTC) integrated circuit manufactured by Texas Instruments. It features an on-chip non-volatile static RAM (NVSRAM) and a CPU supervisor function. The device operates within a supply voltage range of 4.75 V to 5.5 V and supports a time format of HH:MM:SS (24-hour). Key functional capabilities include alarm, calendar, clock, and timer interrupt features. The component is housed in a SOIC-28 surface-mount package and is designed for industrial temperature ranges from -40°C to +85°C.

Feature Summary

• Integrated Non-Volatile Static RAM (NVSRAM) with 16-byte storage capacity
• Parallel bus interface for direct connection to host processors
• Built-in CPU supervisor circuit for system monitoring
• Supports alarm, calendar, clock, and timer interrupt functions

Applications

• Industrial control systems requiring precise timekeeping
• Data logging equipment needing backup memory
• Embedded systems with CPU supervision requirements

Procurement Notes

Verify the specific suffix 'A4TR' against the official Texas Instruments datasheet to confirm tape-and-reel packaging and exact electrical characteristics. Ensure compatibility with existing PCB footprints for the SOIC-28 package. Confirm that the parallel interface timing matches the host controller specifications before integration.

Selection Notes

Select this component when a parallel interface RTC with integrated NVSRAM and CPU supervision is required. Compare pinout and voltage levels with alternative TI models like the BQ4845P or BQ4845YS if different packaging or serial interfaces are preferred. Verify that the 5V operation aligns with the target system power rails.

Part Context

This part belongs to the BQ4845 family of real-time clocks from Texas Instruments. The family includes variants with different packages such as PDIP and SOIC, and interfaces including parallel connections. The BQ4845S-A4TR specifically denotes the SOIC-28 surface-mount variant with the A4TR ordering suffix.

Replacement Considerations

Check for equivalent parts within the BQ4845 series, such as BQ4845S-A4 or BQ4845P-A4, ensuring package and interface compatibility. Cross-reference with other parallel RTCs if pinouts differ.