DS1558W+TRL

Real Time Clock Overview

The DS1558W+TRL is a year 2000-compliant real-time clock/calendar with NV SRAM control, operating at 3.3V in a 48-pin TQFP package. It features a byte-wide parallel interface mapping RTC registers to the top 16 SRAM locations. Key functions include an alarm, watchdog timer, power-on reset, and battery monitor. Timekeeping uses BCD-coded data with automatic leap-year compensation valid until 2100. The device supports dual lithium coin cells for over 10 years of retention. Electrical characteristics specify active current up to 15mA at 3.3V and standby current under 6mA.

Real Time Clock Feature Summary

• Integrated RTC, NV SRAM controller, and power-fail protection circuit
• BCD-coded time/date with automatic leap-year correction valid to 2100
• Programmable watchdog timer and RTC alarm with interrupt output
• Dual battery inputs (VBAT1/VBAT2) for seamless switchover

Real Time Clock Applications

• Systems requiring precise timekeeping during power failures
• Data logging applications needing non-volatile memory backup
• Industrial controllers utilizing watchdog timer functionality
• Embedded systems with 3.3V logic interfaces

Real Time Clock Procurement Notes

Verify the specific ordering suffix +TRL indicates tape-and-reel packaging. Confirm the voltage variant W corresponds to the 3.3V specification. Ensure compatibility with the 48-LQFP/TQFP footprint dimensions. Check for lead-free/RoHS compliance status indicated by the plus sign. Validate that the manufacturer source matches Analog Devices or Maxim Integrated documentation.

Real Time Clock Selection Notes

Select this model for 3.3V systems requiring integrated NV RAM control. Compare against the DS1558Y+ for 5V applications. Consider the DS1558W+ for tray packaging if reel quantities are not required. Verify crystal load capacitance requirements match the internal oscillator design. Ensure address lines A0-A18 are correctly terminated for proper register mapping.

Real Time Clock Part Context

This component belongs to the DS1558 family of watchdog clocks with NV RAM control. It shares architectural similarities with the DS1558Y but operates at a lower supply voltage. The device integrates timing, memory control, and system management functions into a single parallel interface IC.

Real Time Clock Replacement Considerations

DS1558W+ serves as the tray-packaged equivalent. DS1558Y+ provides identical functionality at 5V. DS1558Y+TRL offers the same 5V performance in tape-and-reel format. Cross-verification of pinout and register maps is required when substituting voltage variants.