DS1501YS Equivalent & Substitute Parts

Part Overview

The DS1501YS is a Real Time Clock (RTC) IC with integrated Clock/Calendar functionality, manufactured by Analog Devices Inc./Maxim Integrated. This 28-SOIC surface mount device provides 256 bytes of parallel interface memory with features including alarm capability, leap year compensation, non-volatile SRAM, square wave output, watchdog timer, and Y2K compliance. The device operates from a 4.5V to 5.5V supply with battery backup support from 2.5V to 3.7V.

The DS1501YS is classified as obsolete. Locating equivalent substitute parts is necessary to maintain design continuity, ensure component availability for production, and support long-term system maintenance where original inventory is depleted.

Substiute Parts

DS1501YS

Analog Devices Inc./Maxim IntegratedIn Stock: 930DS1501YS Datasheet

Current PartRFQ

DP8573AVX/NOPB

National SemiconductorIn Stock: 1484DP8573AVX/NOPB Datasheet

MFR RecommendedRFQ

M48T02-150PC1

STMicroelectronicsIn Stock: 1525M48T02-150PC1 Datasheet

MFR RecommendedRFQ

M48T08-150PC1

STMicroelectronicsIn Stock: 1658M48T08-150PC1 Datasheet

MFR RecommendedRFQ

M48T35AV-10MH1F

STMicroelectronicsIn Stock: 5879M48T35AV-10MH1F Datasheet

MFR RecommendedRFQ

M48T37Y-70MH1F

STMicroelectronicsIn Stock: 2256M48T37Y-70MH1F Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the DS1501YS is determined by the following critical parameters:

Primary Substitution Criteria:

• Parallel interface architecture
• Clock/Calendar functionality with 24-hour time format and YY-MM-DD-dd date format
• Supply voltage compatibility within 4.5V ~ 5.5V range
• Operating temperature range of 0°C ~ 70°C or broader
• Presence of core features: Leap Year compensation and Alarm capability
• Surface mount or through-hole mounting compatibility with circuit board design

Secondary Compatibility Factors:

• Battery backup voltage support (2.5V ~ 3.7V preferred but not mandatory)
• Watchdog timer functionality (present in DS1501YS but not all substitutes)
• NVSRAM and square wave output (feature-dependent substitution)
• Package footprint and pin count alignment

The five substitute parts identified below meet the primary criteria. Variations in secondary features, package type, and electrical characteristics are noted in the parameter comparison table.

Parameter Comparison

Engineering Selection Recommendations

DP8573AVX/NOPB (National Semiconductor) This part maintains surface mount configuration and 28-pin LCC packaging. It provides active product status with extended operating temperature range (-40°C to 85°C). Supply voltage and date/time format compatibility are confirmed. The primary trade-off is reduced feature set (Alarm and Leap Year only) and lower timekeeping current consumption (1µA vs. 5mA). This substitute is suitable for applications where extended temperature operation and low power consumption are beneficial and where NVSRAM and square wave output are not required.

M48T02-150PC1 (STMicroelectronics) This Timekeeper® series part offers active product status and ROHS3 compliance. Through-hole 24-DIP packaging requires circuit board redesign. Supply voltage range (4.75V ~ 5.5V) is compatible with the original specification. Leap Year feature is present. This substitute is appropriate for applications where through-hole mounting is acceptable and where reduced pin count (24 vs. 28) does not conflict with circuit requirements.

M48T08-150PC1 (STMicroelectronics) This Timekeeper® series part provides active product status, ROHS3 compliance, and through-hole 28-DIP packaging with pin count matching the original device. Watchdog Timer feature is retained. Supply voltage compatibility is confirmed (4.75V ~ 5.5V). This substitute is suitable for applications where through-hole mounting is acceptable and where feature parity with the original device is prioritized.

M48T35AV-10MH1F (STMicroelectronics) This Timekeeper® series part offers active product status, ROHS3 compliance, and surface mount 28-SOP packaging. Supply voltage operates at 3V ~ 3.6V, which differs from the original 4.5V ~ 5.5V specification. This part is suitable only for applications designed for 3V operation and where the lower supply voltage is compatible with system architecture. SNAPHAT socket requirement must be accommodated in circuit design.

M48T37Y-70MH1F (STMicroelectronics) This Timekeeper® series part provides active product status, ROHS3 compliance, and surface mount 44-BSOP packaging. Supply voltage (4.5V ~ 5.5V) and feature set (Alarm, Leap Year, Watchdog Timer) align closely with the original device. Pin count increases to 44, requiring circuit board redesign. This substitute is appropriate for applications where increased pin count is accommodated and where feature retention is critical. SNAPHAT socket requirement must be integrated into the design.

Frequently Asked Questions (FAQ)

Q: Can the DP8573AVX/NOPB directly replace the DS1501YS without circuit modification?

A: The DP8573AVX/NOPB maintains parallel interface, 28-pin configuration, and surface mount mounting type. However, the package type differs (28-LCC vs. 28-SOIC), requiring PCB footprint verification. Feature set is reduced (Alarm and Leap Year only; NVSRAM, square wave output, and watchdog timer are absent). Electrical compatibility is confirmed for supply voltage and time/date format. Circuit-level testing is required to validate functional equivalence.

Q: Which substitute parts require circuit board redesign?

A: M48T02-150PC1 and M48T08-150PC1 require redesign due to through-hole mounting versus surface mount. M48T35AV-10MH1F and M48T37Y-70MH1F require SNAPHAT socket integration. DP8573AVX/NOPB requires footprint verification due to package type change (LCC vs. SOIC).

Q: Is the M48T35AV-10MH1F compatible with 5V systems?

A: No. The M48T35AV-10MH1F operates at 3V ~ 3.6V supply voltage, which is incompatible with the original DS1501YS specification of 4.5V ~ 5.5V. This part is suitable only for systems designed for 3V operation.

Q: What is the primary difference between M48T08-150PC1 and M48T02-150PC1?

A: Both are through-hole Timekeeper® series parts with active product status and ROHS3 compliance. M48T08-150PC1 provides 28-DIP packaging with Watchdog Timer feature, matching the original pin count and feature set more closely. M48T02-150PC1 provides 24-DIP packaging with Leap Year feature only. Pin count and feature set determine selection based on circuit requirements.

Q: Do all substitute parts support the same battery backup voltage range as the DS1501YS?

A: No. The DS1501YS specifies 2.5V ~ 3.7V battery backup. Only DP8573AVX/NOPB provides battery backup support (2.2V ~ 5.1V). M48T02-150PC1, M48T08-150PC1, M48T35AV-10MH1F, and M48T37Y-70MH1F do not specify battery backup voltage, indicating this feature may not be supported or is not documented in the provided specifications.

Q: Which substitute part offers the best compliance status?

A: All active substitute parts (DP8573AVX/NOPB, M48T02-150PC1, M48T08-150PC1, M48T35AV-10MH1F, M48T37Y-70MH1F) are classified as Active product status. STMicroelectronics parts (M48T02-150PC1, M48T08-150PC1, M48T35AV-10MH1F, M48T37Y-70MH1F) carry ROHS3 compliance certification, whereas the original DS1501YS is RoHS non-compliant. All parts share identical ECCN (EAR99) and HTSUS (8542.39.0001) classifications.

Q: Can the M48T37Y-70MH1F be used as a direct pin-for-pin replacement?

A: No. The M48T37Y-70MH1F uses 44-pin BSOP packaging versus the original 28-pin SOIC, requiring complete circuit board redesign. Pin assignments and functionality differ significantly. This part is suitable only for new designs where the increased pin count and feature set are beneficial.