DS17485S-3 Equivalent & Substitute Parts

Part Overview

The DS17485S-3 is a Real Time Clock (RTC) IC with Clock/Calendar functionality, manufactured by Analog Devices Inc./Maxim Integrated. This device provides 4KB of parallel interface memory with integrated timekeeping, alarm, daylight savings, leap year, NVSRAM, and square wave output capabilities. The part operates across a 2.7V to 3.7V supply range with battery backup support from 2.5V to 3.7V.

The DS17485S-3 is classified as obsolete. Equivalent and substitute parts are necessary to maintain system functionality in applications requiring RTC Clock/Calendar ICs with parallel interface architecture, particularly where the original component is no longer available through standard distribution channels.

Substiute Parts

DS17485S-3

Analog Devices Inc./Maxim IntegratedIn Stock: 845DS17485S-3 Datasheet

Current PartRFQ

BQ4802LYDW

Texas InstrumentsIn Stock: 1993BQ4802LYDW Datasheet

MFR RecommendedRFQ

BQ4802LYPW

Texas InstrumentsIn Stock: 9564BQ4802LYPW Datasheet

MFR RecommendedRFQ

M48T12-70PC1

STMicroelectronicsIn Stock: 2150M48T12-70PC1 Datasheet

MFR RecommendedRFQ

M48T35AV-10MH1F

STMicroelectronicsIn Stock: 5879M48T35AV-10MH1F Datasheet

MFR RecommendedRFQ

M48T58Y-70PC1

STMicroelectronicsIn Stock: 1732M48T58Y-70PC1 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the DS17485S-3 is determined by the following critical parameters:

• Interface Type: Parallel interface requirement
• Time/Date Format: HH:MM:SS (12/24 hr) and YY-MM-DD-dd format support
• Operating Temperature Range: 0°C ~ 70°C
• Supply Voltage Compatibility: Devices operating within or overlapping the 2.7V ~ 3.7V range
• Package Compatibility: Surface mount packages with equivalent pin counts and electrical characteristics
• Feature Set: Presence of alarm, daylight savings, and leap year functionality

Substitute parts are grouped into two categories based on package type and voltage requirements:

Group 1 - Low Voltage Surface Mount (2.7V ~ 3.6V): BQ4802LYDW and BQ4802LYPW from Texas Instruments. These devices maintain the low-voltage supply specification and parallel interface architecture with enhanced features including supervisor and watchdog timer functionality.

Group 2 - Through Hole and Alternative Surface Mount Packages (3V ~ 5.5V): M48T12-70PC1, M48T35AV-10MH1F, and M48T58Y-70PC1 from STMicroelectronics. These Timekeeper® series devices provide parallel interface RTC functionality with different package options and voltage specifications.

Parameter Comparison

Engineering Selection Recommendations

For Low-Voltage 3.3V Systems with Surface Mount Requirements:

BQ4802LYDW and BQ4802LYPW from Texas Instruments are active, ROHS3-compliant alternatives. Both maintain the 2.7V ~ 3.6V supply voltage specification compatible with the DS17485S-3 operating range. BQ4802LYDW is packaged in 28-SOIC (0.295", 7.50mm Width), while BQ4802LYPW uses 28-TSSOP (0.173", 4.40mm Width) for space-constrained applications. Both devices include supervisor and watchdog timer features in addition to core RTC functionality. Current consumption is reduced to 1.5mA typical at operating voltage.

For 5V Systems or Through-Hole Mounting:

M48T12-70PC1 and M48T58Y-70PC1 from STMicroelectronics operate at 4.5V ~ 5.5V and are available in 24-DIP and 28-DIP through-hole packages respectively. These Timekeeper® series devices are active and ROHS3-compliant. M48T12-70PC1 provides 24-pin DIP configuration, while M48T58Y-70PC1 offers 28-pin DIP configuration.

For 3.3V Systems with Alternative Surface Mount Packaging:

M48T35AV-10MH1F from STMicroelectronics operates at 3V ~ 3.6V in a 28-SOP surface mount package with SNAPHAT Sockets. This device is active and ROHS3-compliant with 2mA typical timekeeping current at operating voltage.

All substitute parts maintain parallel interface architecture, support 12/24-hour and YY-MM-DD-dd date/time formats, and operate across the 0°C ~ 70°C temperature range specified for the original device.

Frequently Asked Questions (FAQ)

Q: Can BQ4802LYDW or BQ4802LYPW directly replace DS17485S-3 in a 3.3V application?

A: Both BQ4802 variants operate within the 2.7V ~ 3.6V range, which overlaps the DS17485S-3 specification of 2.7V ~ 3.7V. Pin-level compatibility and firmware requirements must be evaluated for your specific application. The BQ4802 series includes additional supervisor and watchdog timer features not present in the DS17485S-3.

Q: What is the primary difference between BQ4802LYDW and BQ4802LYPW?

A: Both devices are functionally equivalent Texas Instruments RTC ICs with identical electrical specifications. The primary difference is packaging: BQ4802LYDW uses 28-SOIC (0.295", 7.50mm Width), while BQ4802LYPW uses 28-TSSOP (0.173", 4.40mm Width). TSSOP packaging provides a smaller footprint for space-constrained PCB layouts.

Q: Are the STMicroelectronics M48T series devices suitable for 3.3V systems?

A: M48T12-70PC1 and M48T58Y-70PC1 operate at 4.5V ~ 5.5V and are not suitable for 3.3V systems. M48T35AV-10MH1F operates at 3V ~ 3.6V and is compatible with 3.3V supply voltages.

Q: What are the package differences among substitute options?

A: BQ4802LYDW and BQ4802LYPW are surface mount packages (SOIC and TSSOP respectively). M48T12-70PC1 and M48T58Y-70PC1 are through-hole DIP modules. M48T35AV-10MH1F is a surface mount SOP package with SNAPHAT Sockets. PCB design and assembly capabilities determine which package type is appropriate.

Q: Do all substitute parts support 12/24-hour time format like the DS17485S-3?

A: BQ4802LYDW and BQ4802LYPW support 12/24-hour time format. M48T12-70PC1, M48T35AV-10MH1F, and M48T58Y-70PC1 support 24-hour time format only. Applications requiring 12-hour format must use BQ4802 variants.

Q: What is the RoHS compliance status of substitute parts?

A: All substitute parts listed are ROHS3 compliant. The original DS17485S-3 is RoHS non-compliant. Compliance requirements for your application determine whether this distinction is relevant.

Q: How do timekeeping current specifications compare?

A: DS17485S-3 draws 2mA maximum at 2.7V ~ 3.7V. BQ4802LYDW and BQ4802LYPW draw 1.5mA typical at 2.7V ~ 3.6V, providing lower power consumption. M48T12-70PC1 and M48T58Y-70PC1 draw 3mA at 4.5V ~ 5.5V. M48T35AV-10MH1F draws 2mA at 3V ~ 3.6V.