DS1687-3IND Real Time Clock IC Equivalent & Substitute Parts

Part Overview

The DS1687-3IND is a Real Time Clock (RTC) IC with integrated Clock/Calendar functionality, manufactured by Analog Devices Inc./Maxim Integrated. This 24-DIP through-hole component provides 242B of memory with parallel interface, supporting 12/24-hour time format and YY-MM-DD-dd date format. The device is classified as obsolete, making equivalent and substitute parts necessary for ongoing system support and new design implementations.

Substiute Parts

DS1687-3IND

Analog Devices Inc./Maxim IntegratedIn Stock: 2093DS1687-3IND Datasheet

Current PartRFQ

DS1687-3IND+

Analog Devices Inc./Maxim IntegratedIn Stock: 2181DS1687-3IND+ Datasheet

DirectRFQ

BQ4845S-A4TR

Texas InstrumentsIn Stock: 910BQ4845S-A4TR Datasheet

MFR RecommendedRFQ

M48T08-100PC1

STMicroelectronicsIn Stock: 1683M48T08-100PC1 Datasheet

MFR RecommendedRFQ

M48T08-150PC1

STMicroelectronicsIn Stock: 1658M48T08-150PC1 Datasheet

MFR RecommendedRFQ

M48T18-150PC1

STMicroelectronicsIn Stock: 1310M48T18-150PC1 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the DS1687-3IND is determined by the following critical parameters:

Primary Substitution Criteria:

• Interface type (Parallel)
• Time format support (HH:MM:SS with 12/24-hour capability)
• Date format support (YY-MM-DD-dd)
• Mounting type compatibility (Through Hole preferred for direct replacement)
• Package footprint (24-DIP or 28-DIP with pin compatibility considerations)
• Operating temperature range (-40°C ~ 85°C or compatible subset)
• RTC with Clock/Calendar functionality

Substitute Categories:

1. Direct Equivalent (Same Package): DS1687-3IND+ maintains identical electrical and mechanical specifications with active product status and improved RoHS compliance.

2. Functional Equivalents (Different Package): BQ4845S-A4TR, M48T08-100PC1, M48T08-150PC1, and M48T18-150PC1 provide equivalent RTC Clock/Calendar functionality with parallel interface but differ in package type (28-SOIC or 28-DIP), voltage supply ranges, and operating temperature specifications.

Parameter Comparison

Engineering Selection Recommendations

DS1687-3IND+ (Direct Equivalent): This part is the primary substitute for DS1687-3IND. It maintains identical electrical specifications, package footprint, and functional characteristics while offering active product status and ROHS3 compliance. This part is suitable for direct replacement in existing designs without circuit modification.

BQ4845S-A4TR (Texas Instruments): This substitute provides equivalent RTC Clock/Calendar functionality with parallel interface and active product status. However, it requires surface-mount assembly (28-SOIC package) instead of through-hole mounting, necessitating PCB redesign. The operating temperature range is limited to 0°C ~ 70°C, which does not cover the full -40°C ~ 85°C range of the original part. Supply voltage operates at 4.75V ~ 5.5V, requiring circuit voltage adjustment from the original 2.7V ~ 3.7V specification.

M48T08-100PC1 and M48T08-150PC1 (STMicroelectronics): These parts provide equivalent RTC Clock/Calendar functionality in 28-DIP through-hole packages with active product status and ROHS3 compliance. Operating temperature range is limited to 0°C ~ 70°C. Supply voltage operates at 4.75V ~ 5.5V, requiring circuit voltage adjustment. The 28-DIP package requires PCB layout modification compared to the 24-DIP original.

M48T18-150PC1 (STMicroelectronics): This part provides equivalent RTC Clock/Calendar functionality in 28-DIP through-hole package with active product status and ROHS3 compliance. Operating temperature range is limited to 0°C ~ 70°C. Supply voltage operates at 4.5V ~ 5.5V, requiring circuit voltage adjustment. The 28-DIP package requires PCB layout modification compared to the 24-DIP original.

Frequently Asked Questions (FAQ)

Q: Can DS1687-3IND+ be used as a direct replacement for DS1687-3IND?

A: Yes. DS1687-3IND+ maintains identical electrical specifications, package footprint (24-DIP), mounting type (through-hole), voltage supply ranges (2.7V ~ 3.7V), operating temperature range (-40°C ~ 85°C), and functional characteristics. No circuit modification is required.

Q: What are the key differences between DS1687-3IND and the STMicroelectronics M48T series substitutes?

A: The primary differences are package type (24-DIP vs. 28-DIP), supply voltage (2.7V ~ 3.7V vs. 4.75V ~ 5.5V or 4.5V ~ 5.5V), and operating temperature range (-40°C ~ 85°C vs. 0°C ~ 70°C). These differences require circuit redesign and voltage supply adjustment.

Q: Is BQ4845S-A4TR suitable for through-hole PCB assembly?

A: No. BQ4845S-A4TR uses 28-SOIC surface-mount package, requiring surface-mount assembly and PCB redesign. It is not compatible with through-hole mounting applications.

Q: Do all substitute parts support 12/24-hour time format like the original DS1687-3IND?

A: No. DS1687-3IND and DS1687-3IND+ support 12/24-hour time format. The STMicroelectronics M48T08 and M48T18 series support 24-hour time format only. BQ4845S-A4TR supports 12/24-hour time format.

Q: What is the operating temperature limitation when using M48T series substitutes?

A: M48T08-100PC1, M48T08-150PC1, and M48T18-150PC1 operate within 0°C ~ 70°C range, which does not cover the full -40°C ~ 85°C range of the original DS1687-3IND. Applications requiring extended temperature operation must use DS1687-3IND+ or evaluate alternative solutions.

Q: Are all substitute parts RoHS3 compliant?

A: DS1687-3IND+ is ROHS3 compliant. BQ4845S-A4TR, M48T08-100PC1, M48T08-150PC1, and M48T18-150PC1 are all ROHS3 compliant. The original DS1687-3IND is RoHS non-compliant.