DS1742-70 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 through-hole 24-DIP module operates at 4.5V to 5.5V supply voltage and includes features such as leap year support, Y2K compliance, and parallel interface connectivity. The product is currently obsolete, making equivalent and substitute parts necessary for legacy system maintenance, board redesigns, and component sourcing.

Substiute Parts

DS1742-70

Analog Devices Inc./Maxim IntegratedIn Stock: 1281DS1742-70 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 Compatibility Criteria:

• Parallel interface connectivity
• 24-hour time format (HH:MM:SS)
• Date format support (YY-MM-DD-dd)
• Operating temperature range (0°C ~ 70°C)
• Supply voltage compatibility (4.5V ~ 5.5V or overlapping range)
• RoHS3 compliance and REACH unaffected status

Package Considerations:

• Through-hole mounting is preferred for direct socket replacement
• Surface-mount alternatives require PCB redesign and adapter solutions

Substitute Parts Grouped by Mounting Type:

Group 1: Through-Hole Direct Replacements (24-DIP)

• M48T12-150PC1 (STMicroelectronics) – Identical package, matching voltage and current specifications
• M48T58-70PC1 (STMicroelectronics) – 28-DIP package, requires pin mapping verification

Group 2: Surface-Mount Alternatives (24-SOIC)

• BQ3285S-SB2 (Texas Instruments) – Reduced pin count, requires circuit redesign

Group 3: Surface-Mount Alternatives (28-SOIC/28-SOP)

• BQ4802LYDWR (Texas Instruments) – Lower voltage operation (2.7V ~ 3.6V), requires power supply modification
• M48T08Y-10MH1F (STMicroelectronics) – 28-SOP with SNAPHAT sockets, requires mechanical adaptation

Parameter Comparison

Engineering Selection Recommendations

For Direct Socket Replacement (Preferred): Select M48T12-150PC1 (STMicroelectronics). This part maintains identical 24-DIP through-hole packaging, matching supply voltage range (4.5V ~ 5.5V), equivalent timekeeping current (3mA @ 4.5V ~ 5.5V), and active product status. RoHS3 compliance and unlimited MSL rating ensure regulatory and environmental compatibility with the original DS1742-70.

For Pin-Compatible Through-Hole Substitution: M48T58-70PC1 (STMicroelectronics) provides a 28-DIP through-hole alternative with matching voltage specifications and active product status. Pin mapping verification is required due to increased pin count.

For Surface-Mount Redesigns: BQ3285S-SB2 (Texas Instruments) offers a 24-SOIC package with parallel interface, 24-hour time format support, and active product status. This option requires PCB layout modification but maintains voltage compatibility (4.5V ~ 5.5V).

For Low-Power Applications: BQ4802LYDWR (Texas Instruments) operates at reduced supply voltage (2.7V ~ 3.6V) with lower timekeeping current (1.5mA typical). This part requires power supply redesign and is suitable only for systems capable of operating at 2.7V to 3.6V.

All recommended substitutes maintain ROHS3 compliance, REACH unaffected status, and operating temperature range (0°C ~ 70°C) alignment with the original part.

Frequently Asked Questions (FAQ)

Q: Can M48T12-150PC1 replace DS1742-70 without circuit modification? A: Yes. M48T12-150PC1 matches the 24-DIP through-hole package, supply voltage range (4.5V ~ 5.5V), and parallel interface specifications. Direct socket substitution is possible without circuit redesign.

Q: What is the primary difference between M48T12-150PC1 and M48T58-70PC1? A: M48T12-150PC1 uses a 24-DIP package with 24 pins, while M48T58-70PC1 uses a 28-DIP package with 28 pins. Both maintain through-hole mounting and 4.5V ~ 5.5V supply voltage compatibility. Pin mapping must be verified before substitution.

Q: Why does BQ4802LYDWR require power supply modification? A: BQ4802LYDWR operates at 2.7V ~ 3.6V supply voltage, whereas DS1742-70 requires 4.5V ~ 5.5V. Systems designed for 5V operation must be redesigned to accommodate the lower voltage range.

Q: Are surface-mount alternatives suitable for legacy board designs? A: Surface-mount alternatives (BQ3285S-SB2, BQ4802LYDWR, M48T08Y-10MH1F) require PCB redesign and are not suitable for direct socket replacement in through-hole designs. These options are applicable only for new board layouts or retrofit designs with adapter solutions.

Q: What does MSL rating indicate for component handling? A: Moisture Sensitivity Level (MSL) specifies the maximum time a component can be exposed to ambient conditions before soldering. DS1742-70 and most substitutes carry MSL 1 (Unlimited), indicating no moisture sensitivity restrictions. M48T08Y-10MH1F carries MSL 3 (168 Hours), requiring controlled storage and handling procedures.

Q: Are all substitute parts RoHS3 compliant? A: Yes. All listed substitute parts (M48T12-150PC1, M48T58-70PC1, BQ3285S-SB2, BQ4802LYDWR, M48T08Y-10MH1F) are ROHS3 compliant and REACH unaffected, matching the regulatory status of DS1742-70.

Q: What is the significance of active product status for substitutes? A: Active product status indicates ongoing manufacturing and availability from the supplier. All recommended substitutes maintain active status, ensuring long-term component availability and supply chain reliability compared to the obsolete DS1742-70.