DS1558Y+

Real Time Clock Overview

The DS1558Y+ is a 5V Real-Time Clock (RTC) with NV RAM control in a 48-pin TQFP package. It integrates an RTC, watchdog timer, and power-fail controller. The device uses a parallel interface to access BCD-coded time registers mapped into the top 16 locations of the SRAM address space. Operating voltage ranges from 4.5V to 5.5V. It supports battery backup via VBAT pins for over 10 years of data retention. Features include programmable alarms, interrupt outputs, and automatic leap-year compensation valid until 2100.

Real Time Clock Feature Summary

• Integrated RTC, watchdog timer, and NV SRAM controller with parallel interface
• BCD-coded clock/calendar with automatic leap-year compensation valid to 2100
• Programmable alarm and watchdog timer with interrupt/frequency test output
• Precise power-on reset and power-fail write protection circuitry

Real Time Clock Applications

• Industrial systems requiring precise timekeeping and data retention
• Embedded controllers needing watchdog timer functionality
• Systems utilizing external static RAM with RTC register mapping

Real Time Clock Procurement Notes

Verify lead-free status through the '+' suffix confirmation. Confirm the specific voltage variant matches system requirements, as the Y suffix denotes 5V operation. Check for available documentation regarding device errata on the manufacturer's website before finalizing procurement specifications.

Real Time Clock Selection Notes

Select the DS1558Y+ when a 5V supply is required. Ensure the design accommodates the 48-pin TQFP footprint. Verify that the external SRAM address decoding correctly isolates the upper 16 addresses for RTC access. Confirm crystal load capacitance matches the internal oscillator requirements of 6pF.

Real Time Clock Part Context

This component belongs to the DS1558 family of watchdog clocks with NV RAM control. The 'Y' designation specifically indicates the 5.0V operating voltage version. The '+' suffix confirms compliance with lead-free/RoHS standards. It shares functional similarities with the 3.3V DS1558W variant but operates at standard logic levels.

Real Time Clock Replacement Considerations

The DS1558W+ serves as a direct functional substitute if the application requires 3.3V operation instead of 5V. Both variants share identical pinouts and register maps within the 48-TQFP package.