DS1678 Real Time Clock IC - Equivalent & Substitute Parts

Part Overview

The DS1678 is a Real Time Clock (RTC) Time Event Recorder IC manufactured by Analog Devices Inc./Maxim Integrated, designed for applications requiring precise timekeeping with alarm functionality and non-volatile static RAM (NVSRAM). The device operates as a 32-byte I2C/2-Wire Serial interface component in an 8-DIP through-hole package.

The DS1678 is classified as obsolete. Equivalent and substitute parts are necessary to support ongoing system maintenance, new design implementations, and supply chain continuity where original components are no longer readily available or manufactured.

Substiute Parts

DS1678

Analog Devices Inc./Maxim IntegratedIn Stock: 1049DS1678 Datasheet

Current PartRFQ

RX-8035SA:AC0 PURE SN

EPSONIn Stock: 976RX-8035SA:AC0 PURE SN Datasheet

MFR RecommendedRFQ

RX8130CE B0

EPSONIn Stock: 8065RX8130CE B0 Datasheet

MFR RecommendedRFQ

RX8130CE:BB

EPSONIn Stock: 936RX8130CE:BB Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the DS1678 is determined by the following critical parameters:

Primary Compatibility Criteria:

• I2C/2-Wire Serial interface protocol compatibility
• Time format support (HH:MM:SS with 12/24 hour capability)
• Date format support (YY-MM-DD-dd)
• Alarm functionality
• Operating temperature range (-40°C ~ 85°C)
• Supply voltage compatibility within specified ranges

Secondary Considerations:

• Package type (through-hole vs. surface mount affects PCB integration)
• RoHS compliance status (regulatory requirement for new designs)
• Product status (active vs. obsolete affects long-term availability)
• Current consumption characteristics

The substitute parts identified—RX-8035SA:AC0 PURE SN, RX8130CE B0, and RX8130CE:BB—all satisfy the core functional requirements of I2C interface, time/date format support, alarm capability, and operating temperature range. However, they differ in packaging, mounting technology, and compliance certifications.

Parameter Comparison

Engineering Selection Recommendations

For Direct Functional Replacement (Existing Through-Hole Designs):

The RX-8035SA:AC0 PURE SN provides the closest functional match to the DS1678, maintaining explicit HH:MM:SS (12/24 hour) and YY-MM-DD-dd date format support. This part is active, ROHS3 compliant, and operates within the required temperature range. The 14-SOIC package requires PCB redesign from the original 8-DIP through-hole configuration.

For Surface Mount Integration (New Designs):

The RX8130CE B0 and RX8130CE:BB are functionally equivalent alternatives optimized for surface mount assembly. Both parts are active products with ROHS3 compliance and superior low-power characteristics (0.5µA @ 3V timekeeping current). The 10-SMD no-lead package represents modern manufacturing standards. These parts are suitable for new system designs where PCB layout can accommodate surface mount technology.

Compliance Considerations:

All substitute parts are ROHS3 compliant, addressing regulatory requirements for new product development. The DS1678's RoHS non-compliant status restricts its use in applications subject to RoHS directives. Selection of substitute parts should align with target market regulatory requirements and product lifecycle phase.

Frequently Asked Questions (FAQ)

Q: Can the RX-8035SA:AC0 PURE SN directly replace the DS1678 in existing PCB designs?

A: Functional compatibility is confirmed through I2C interface, time/date format support, and alarm capability. However, package incompatibility requires PCB redesign. The DS1678 uses 8-DIP through-hole mounting, while the RX-8035SA:AC0 uses 14-SOIC surface mount. Adapter solutions or board-level redesign are necessary for physical integration.

Q: What are the key differences between RX8130CE B0 and RX8130CE:BB?

A: Both parts are electrically and functionally identical. The primary difference is packaging format: RX8130CE B0 is supplied in Tape & Reel (TR), while RX8130CE:BB is supplied in Bulk. Selection depends on procurement volume and assembly line requirements. Both use 10-SMD no-lead packages and are ROHS3 compliant.

Q: Are the RX8130CE variants suitable for battery-backed timekeeping applications?

A: The RX8130CE B0 and RX8130CE:BB datasheets do not specify battery supply voltage ranges. The RX-8035SA:AC0 PURE SN specifies 1V ~ 5.5V battery supply capability. For applications requiring battery backup, the RX-8035SA:AC0 PURE SN is the recommended substitute.

Q: What is the impact of switching from through-hole to surface mount packaging?

A: Surface mount packages (14-SOIC and 10-SMD) require different PCB layout, assembly processes, and test fixtures compared to through-hole 8-DIP packages. Surface mount technology offers improved density, automated assembly compatibility, and modern manufacturing alignment. Through-hole designs require manual or specialized assembly equipment.

Q: How does the operating voltage range affect substitution decisions?

A: The DS1678 operates at 4.5V ~ 5.5V. All substitute parts accept this range and extend compatibility to lower voltages (RX-8035SA:AC0 at 2.4V minimum; RX8130CE variants at 1.25V minimum). This expanded voltage range provides design flexibility but does not restrict substitution in existing 5V systems.

Q: Are there any memory or feature limitations with the substitute parts?

A: The DS1678 includes 32 bytes NVSRAM and Y2K/Leap Year features. The substitute parts specify alarm functionality but do not document equivalent NVSRAM capacity or Y2K features in the provided parameters. System-level verification is required if these specific features are critical to application requirements.