DS1643-100 Equivalent & Substitute Parts

Part Overview

The DS1643-100 is a Real Time Clock (RTC) IC with integrated Clock/Calendar functionality and 8KB parallel NVSRAM, manufactured by Analog Devices Inc./Maxim Integrated. This component operates in the 4.5V to 5.5V supply range and is packaged in a 28-DIP module (0.600", 15.24mm) with through-hole mounting. The DS1643-100 is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing system support.

Substiute Parts

DS1643-100

Analog Devices Inc./Maxim IntegratedIn Stock: 2254DS1643-100 Datasheet

Current PartRFQ

BQ4802LYDWR

Texas InstrumentsIn Stock: 3828BQ4802LYDWR Datasheet

MFR RecommendedRFQ

DP8573AV/NOPB

Texas InstrumentsIn Stock: 4247DP8573AV/NOPB Datasheet

MFR RecommendedRFQ

M48T08-100PC1

STMicroelectronicsIn Stock: 1683M48T08-100PC1 Datasheet

MFR RecommendedRFQ

M48T58-70PC1

STMicroelectronicsIn Stock: 1546M48T58-70PC1 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the DS1643-100 is determined by the following critical parameters:

Primary Substitution Criteria:

• Parallel interface for direct pin compatibility
• 28-pin package configuration
• Clock/Calendar functionality with HH:MM:SS (24 hr) time format and YY-MM-DD-dd date format
• Operating temperature range of 0°C ~ 70°C
• Supply voltage compatibility within 4.5V ~ 5.5V range

Substitution Groups:

Group 1: Direct Package Match (28-DIP Through Hole)

• M48T08-100PC1 (STMicroelectronics)
• M48T58-70PC1 (STMicroelectronics)

These parts maintain identical 28-DIP through-hole packaging, matching mechanical and electrical interface requirements. Both support 24-hour time format and YY-MM-DD-dd date format with operating temperature range 0°C ~ 70°C and supply voltage 4.75V ~ 5.5V.

Group 2: Functional Equivalents (Different Package)

• BQ4802LYDWR (Texas Instruments) - 28-SOIC surface mount
• DP8573AV/NOPB (Texas Instruments) - 28-LCC (J-Lead) surface mount

These parts provide equivalent clock/calendar functionality with parallel interface but require PCB redesign due to surface-mount packaging. BQ4802LYDWR operates at 2.7V ~ 3.6V supply. DP8573AV/NOPB maintains 4.5V ~ 5.5V supply compatibility and extended operating temperature range (-40°C ~ 85°C).

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (No PCB Redesign Required):

M48T08-100PC1 and M48T58-70PC1 are the primary substitutes for through-hole applications. Both maintain identical 28-DIP packaging and mechanical compatibility. M48T08-100PC1 includes watchdog timer functionality, while M48T58-70PC1 provides a streamlined feature set. Both are ROHS3 compliant and actively manufactured, addressing the obsolescence of the DS1643-100. Supply voltage range (4.75V ~ 5.5V) is compatible with systems designed for 4.5V ~ 5.5V operation.

For New Designs with PCB Redesign:

DP8573AV/NOPB offers extended operating temperature range (-40°C ~ 85°C) and significantly lower timekeeping current (1µA @ 5V), making it suitable for applications requiring enhanced thermal performance or reduced power consumption. This part maintains 4.5V ~ 5.5V supply compatibility and ROHS3 compliance.

BQ4802LYDWR is suitable only for systems operating at 2.7V ~ 3.6V supply voltage. This part is not compatible with 5V systems and requires complete circuit redesign.

Frequently Asked Questions (FAQ)

Q: Can M48T08-100PC1 or M48T58-70PC1 be used as direct pin-for-pin replacements for DS1643-100?

A: Yes. Both parts are packaged in 28-DIP modules with 0.600" (15.24mm) spacing, matching the DS1643-100 footprint exactly. Parallel interface, time format (HH:MM:SS 24 hr), date format (YY-MM-DD-dd), and operating temperature range (0°C ~ 70°C) are functionally equivalent. Supply voltage range (4.75V ~ 5.5V) is compatible with 4.5V ~ 5.5V systems.

Q: What is the key difference between M48T08-100PC1 and M48T58-70PC1?

A: M48T08-100PC1 includes watchdog timer functionality, while M48T58-70PC1 does not. Both provide identical clock/calendar performance, parallel interface, and 28-DIP packaging. Selection depends on whether watchdog timer capability is required in the application.

Q: Why is BQ4802LYDWR not recommended as a direct replacement?

A: BQ4802LYDWR operates at 2.7V ~ 3.6V supply voltage, incompatible with the DS1643-100 specification of 4.5V ~ 5.5V. Additionally, it is packaged in 28-SOIC surface mount, requiring PCB redesign. This part is suitable only for new 3.3V designs.

Q: Can DP8573AV/NOPB be used in existing DS1643-100 applications?

A: DP8573AV/NOPB provides functional equivalence in clock/calendar operation and maintains 4.5V ~ 5.5V supply compatibility. However, it is packaged in 28-LCC (J-Lead) surface mount, requiring PCB redesign. The extended operating temperature range (-40°C ~ 85°C) and reduced timekeeping current (1µA @ 5V) make it suitable for new designs with enhanced thermal or power requirements.

Q: Are all substitute parts RoHS compliant?

A: M48T08-100PC1, M48T58-70PC1, BQ4802LYDWR, and DP8573AV/NOPB are all ROHS3 compliant. The original DS1643-100 is RoHS non-compliant. Substitution addresses both obsolescence and regulatory compliance requirements.

Q: What is the moisture sensitivity level (MSL) for substitute parts?

A: M48T08-100PC1 and M48T58-70PC1 have MSL 1 (Unlimited). BQ4802LYDWR has MSL 1 (Unlimited). DP8573AV/NOPB has MSL 2A (4 Weeks). All parts are suitable for standard handling and storage conditions.