DS1687-3 Real Time Clock IC Equivalent & Substitute Parts

Part Overview

The DS1687-3 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 242 bytes of NVSRAM, alarm capability, square wave output, and Y2K compliance. The DS1687-3 is classified as obsolete, making equivalent and substitute parts necessary for ongoing system support, maintenance, and new design implementations where through-hole or low-voltage operation is required.

Substiute Parts

DS1687-3

Analog Devices Inc./Maxim IntegratedIn Stock: 1461DS1687-3 Datasheet

Current PartRFQ

DS1685SN-5+

Analog Devices Inc./Maxim IntegratedIn Stock: 979DS1685SN-5+ Datasheet

DirectRFQ

DS1687-3+

Analog Devices Inc./Maxim IntegratedIn Stock: 1723DS1687-3+ Datasheet

DirectRFQ

M48T02-70PC1

STMicroelectronicsIn Stock: 1276M48T02-70PC1 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

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

Functional Compatibility: Clock/Calendar type, parallel interface, 242B memory, alarm and square wave output features, and Y2K compliance.

Electrical Compatibility: Supply voltage range (primary and battery), timekeeping current consumption, and operating temperature range.

Physical Compatibility: Package type (24-DIP through-hole form factor with 0.600" width).

Regulatory Compliance: RoHS and REACH status for applications requiring modern component standards.

Two substitute categories exist:

Direct Functional Equivalent (Same Package): DS1687-3+ maintains identical electrical specifications and through-hole 24-DIP packaging, differing only in product status (Active vs. Obsolete) and RoHS compliance.

Cross-Family Substitute (Different Package): DS1685SN-5+ provides equivalent Clock/Calendar functionality with identical memory and features but uses surface-mount 24-SOIC packaging and operates at 4.5V ~ 5.5V supply voltage.

Manufacturer-Recommended Substitute (Different Voltage/Manufacturer): M48T02-70PC1 from STMicroelectronics maintains through-hole 24-DIP packaging and operating temperature range but operates at 4.75V ~ 5.5V supply voltage and lacks battery backup voltage specification.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Recommended Primary Option): DS1687-3+ is the optimal substitute. It maintains identical electrical specifications (2.7V ~ 3.7V supply, 2mA timekeeping current, 0°C ~ 70°C operating range), identical package geometry (24-DIP through-hole), and all functional features (Alarm, NVSRAM, Square Wave Output, Y2K). The primary advantage is Active product status and ROHS3 compliance, eliminating obsolescence risk and meeting modern regulatory requirements.

For Surface-Mount Applications: DS1685SN-5+ provides equivalent Clock/Calendar functionality with identical memory and features but requires circuit redesign for surface-mount implementation. This substitute operates at higher supply voltage (4.5V ~ 5.5V) and extended temperature range (-40°C ~ 85°C), making it suitable for applications with different power budgets and thermal requirements.

For Voltage-Flexible Designs: M48T02-70PC1 maintains through-hole 24-DIP packaging and operating temperature range but operates at 4.75V ~ 5.5V supply voltage. This substitute is applicable only to systems designed for 5V operation. Battery backup voltage specification is not provided for this part.

Compliance Consideration: All active substitutes (DS1687-3+, DS1685SN-5+, M48T02-70PC1) are ROHS3 compliant, addressing regulatory requirements for new designs and system upgrades where RoHS compliance is mandatory.

Frequently Asked Questions (FAQ)

Q: Can DS1687-3+ directly replace DS1687-3 without circuit modification?

A: Yes. DS1687-3+ is a direct equivalent with identical supply voltage (2.7V ~ 3.7V), timekeeping current (2mA @ 3V), operating temperature (0°C ~ 70°C), and 24-DIP through-hole package geometry. No circuit redesign is required.

Q: What is the primary difference between DS1687-3 and DS1687-3+?

A: DS1687-3 is obsolete with RoHS non-compliant status. DS1687-3+ is Active with ROHS3 compliance. Electrical and functional specifications are identical.

Q: Can DS1685SN-5+ replace DS1687-3 in existing through-hole designs?

A: No direct board-level replacement is possible. DS1685SN-5+ uses surface-mount 24-SOIC packaging (0.295" width) versus through-hole 24-DIP (0.600" width). Circuit board redesign and rework are required. Additionally, supply voltage differs (4.5V ~ 5.5V vs. 2.7V ~ 3.7V), requiring power supply circuit modification.

Q: Is M48T02-70PC1 suitable for 3V systems?

A: No. M48T02-70PC1 requires 4.75V ~ 5.5V supply voltage and is not rated for 3V operation. It is applicable only to systems designed for 5V supply.

Q: What are the key parameters that determine substitution compatibility?

A: Supply voltage range, timekeeping current consumption, operating temperature range, package type (through-hole vs. surface-mount), memory size, interface type (parallel), and functional features (Alarm, NVSRAM, Square Wave Output, Y2K compliance).

Q: Are all substitute parts ROHS3 compliant?

A: Yes. DS1687-3+, DS1685SN-5+, and M48T02-70PC1 are all ROHS3 compliant. The original DS1687-3 is RoHS non-compliant.

Q: Which substitute is recommended for new designs?

A: DS1687-3+ is recommended for new designs requiring through-hole mounting and low-voltage operation (2.7V ~ 3.7V). It provides identical functionality to the obsolete DS1687-3 with Active product status and modern compliance certifications.