DS1742-70+ Real Time Clock IC Equivalent & Substitute Parts

Part Overview

The DS1742-70+ is a Real Time Clock (RTC) IC with integrated Clock/Calendar functionality and 2KB of Nonvolatile Static RAM (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 24-DIP Module (0.600", 15.24mm) through-hole configuration. The device is classified as obsolete, making equivalent and substitute parts necessary for ongoing system support and new design implementations.

Substiute Parts

DS1742-70+

Analog Devices Inc./Maxim IntegratedIn Stock: 3928DS1742-70+ Datasheet

Current PartRFQ

BQ3285S-SB2

Texas InstrumentsIn Stock: 1987BQ3285S-SB2 Datasheet

MFR RecommendedRFQ

BQ4802LYDWR

Texas InstrumentsIn Stock: 3828BQ4802LYDWR Datasheet

MFR RecommendedRFQ

M48T08Y-10MH1F

STMicroelectronicsIn Stock: 1165M48T08Y-10MH1F Datasheet

MFR RecommendedRFQ

M48T12-150PC1

STMicroelectronicsIn Stock: 2537M48T12-150PC1 Datasheet

MFR RecommendedRFQ

M48T35AV-10PC1

STMicroelectronicsIn Stock: 1390M48T35AV-10PC1 Datasheet

MFR RecommendedRFQ

M48T58-70PC1

STMicroelectronicsIn Stock: 1546M48T58-70PC1 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the DS1742-70+ is determined by the following critical parameters:

Primary Substitution Criteria:

• Parallel interface for direct pin compatibility
• 24-hour time format (HH:MM:SS)
• YY-MM-DD-dd date format
• Operating temperature range: 0°C ~ 70°C
• RoHS3 compliance
• Through-hole mounting (24-DIP package preferred for direct replacement)

Secondary Compatibility Factors:

• Supply voltage range (4.5V ~ 5.5V preferred; 3V ~ 3.6V acceptable with design review)
• Timekeeping current consumption
• Memory capacity and NVSRAM functionality
• Leap year support

Substitute parts are grouped into two categories:

Category A - Direct Package Replacement (24-DIP Through-Hole): Parts maintaining identical 24-DIP through-hole packaging for direct PCB substitution without layout modification.

Category B - Functional Equivalents (Alternative Packages): Parts providing equivalent RTC/Clock-Calendar functionality with different package types (SOIC, SOP) requiring PCB redesign or adapter solutions.

Parameter Comparison

Engineering Selection Recommendations

For Direct PCB Replacement (No Layout Modification):

M48T12-150PC1 is the primary substitute for DS1742-70+. Both components feature identical 24-DIP through-hole packaging (0.600", 15.24mm), matching supply voltage range (4.5V ~ 5.5V), 24-hour time format, and equivalent timekeeping current consumption (3mA @ 5V). M48T12-150PC1 is manufactured by STMicroelectronics and maintains active product status with ROHS3 compliance. This part enables direct socket substitution without PCB redesign.

M48T58-70PC1 provides functional equivalence with 28-DIP through-hole packaging. The supply voltage range (4.75V ~ 5.5V) is compatible with 5V systems. The 28-pin package requires PCB layout modification but maintains parallel interface and 24-hour time format compatibility.

For Systems Requiring Surface Mount Technology:

BQ3285S-SB2 (Texas Instruments, 24-SOIC) and M48T08Y-10MH1F (STMicroelectronics, 28-SOP) provide surface-mount alternatives. Both maintain 4.5V ~ 5.5V supply compatibility and parallel interface operation. These options require PCB redesign and are suitable for new designs or systems undergoing modernization.

BQ4802LYDWR operates at reduced supply voltage (2.7V ~ 3.6V) and includes additional features (Supervisor, Watchdog Timer). This part is appropriate for low-power applications but requires design verification for voltage compatibility.

M48T35AV-10PC1 operates at 3V ~ 3.6V supply range and is packaged in 28-DIP through-hole format. This option is suitable for 3.3V systems with through-hole mounting requirements.

Compliance and Availability:

All substitute parts maintain ROHS3 compliance and active product status, ensuring long-term availability and regulatory compliance. Selection should prioritize parts matching the original supply voltage specification (4.5V ~ 5.5V) unless system redesign permits voltage adjustment.

Frequently Asked Questions (FAQ)

Q: Can M48T12-150PC1 replace DS1742-70+ without PCB modification?

A: Yes. M48T12-150PC1 is packaged in identical 24-DIP through-hole format (0.600", 15.24mm) with matching pin count and supply voltage range (4.5V ~ 5.5V). Direct socket substitution is possible without layout changes.

Q: What is the key difference between 24-DIP and 28-DIP packages?

A: The 24-DIP package contains 24 pins while the 28-DIP package contains 28 pins. Direct substitution between these packages requires PCB redesign. M48T58-70PC1 and M48T35AV-10PC1 use 28-DIP packaging and cannot be directly inserted into 24-DIP sockets.

Q: Are surface-mount alternatives (BQ3285S-SB2, BQ4802LYDWR, M48T08Y-10MH1F) compatible with existing through-hole PCBs?

A: No. Surface-mount packages (SOIC, SOP) require different PCB footprints and soldering processes. These parts are suitable for new designs or systems undergoing PCB redesign. Adapter boards may provide temporary compatibility but are not recommended for production use.

Q: Does BQ4802LYDWR operate at the same voltage as DS1742-70+?

A: No. BQ4802LYDWR operates at 2.7V ~ 3.6V supply range, while DS1742-70+ requires 4.5V ~ 5.5V. BQ4802LYDWR is suitable for 3.3V systems only and requires design verification before substitution.

Q: Which substitute part has the closest electrical specifications to DS1742-70+?

A: M48T12-150PC1 provides the closest match with identical 24-DIP packaging, 4.5V ~ 5.5V supply range, 24-hour time format, and equivalent timekeeping current (3mA @ 5V). This part is the recommended primary substitute.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts maintain ROHS3 compliance, matching the environmental and regulatory status of DS1742-70+.

Q: What is the significance of "Active" product status for substitute parts?

A: Active product status indicates ongoing manufacturing and long-term availability. All substitute parts listed maintain active status, ensuring continued supply and support compared to the obsolete DS1742-70+.