BQ4802LYDSH

Overview

The BQ4802LYDSH is a parallel real-time clock with CPU supervisor and external SRAM nonvolatile memory backup, manufactured by Texas Instruments. It operates at 3.3 V within a supply voltage range of 2.7 V to 3.6 V. The device integrates a time-of-day clock, century-based calendar, and watchdog timer in a 28-pin SNAPHAT package (DSH). It features less than 500 nA of clock operation current in backup mode and includes an on-chip battery-backup switchover circuit for external SRAM. The RTC counts seconds through centuries in BCD format and supports independent periodic and alarm interrupts active in battery-backup mode.

Feature Summary

• Parallel interface with 16 bytes of clock and control registers
• On-chip battery-backup switchover circuit with nonvolatile control for external SRAM
• Microprocessor reset with push-button override and programmable watchdog timer
• Power-fail interrupt warning and battery-low warning

Applications

• Telecommunications base stations
• Servers
• Handheld data collection equipment
• Medical equipment
• Test equipment

Procurement Notes

Verify the specific ordering suffix against the manufacturer's latest documentation to confirm package type and availability status. The DSH package requires the bq48SH-28x6 component to complete the two-piece module. Check for end-of-life notifications as older revisions may be discontinued.

Selection Notes

Select the BQ4802LY variant for 3.3-V systems; use BQ4802Y for 5-V applications. Ensure the external crystal meets the specified load capacitance of 6 pF. Confirm that the system design accommodates the SNAPHAT socket requirements and that the BC pin is connected to a valid 3-V backup cell upon power-up.

Part Context

This part belongs to the BQ4802 family of parallel real-time clocks. The LY designation indicates 3.3-V operation, while the DSH suffix denotes the SNAPHAT package option. This package is distinct from standard SOIC or TSSOP variants and requires specific mounting considerations.

Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided source material.