DS1501YS+ Real Time Clock IC - 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 device provides 256 bytes of parallel interface memory with comprehensive timekeeping features including alarm capability, leap year compensation, non-volatile SRAM, square wave output, and watchdog timer functionality. The part is classified as obsolete, making equivalent substitute components necessary for new designs and ongoing system support. Substitute parts must maintain functional compatibility across timekeeping accuracy, memory capacity, interface protocol, and electrical operating parameters.

Substiute Parts

DS1501YS+

Analog Devices Inc./Maxim IntegratedIn Stock: 1026DS1501YS+ 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 logic for the DS1501YS+ is based on the following critical parameters that must be maintained or exceeded:

Primary Compatibility Criteria:

• Interface type: Parallel (required for pin-level compatibility)
• Time format: HH:MM:SS with 24-hour capability
• Date format: YY-MM-DD-dd support
• Supply voltage range: Must support 4.5V ~ 5.5V operation
• Operating temperature range: Minimum 0°C ~ 70°C
• Product status: Active preferred (obsolete parts present supply risk)
• RoHS compliance: ROHS3 Compliant

Secondary Considerations:

• Memory capacity: 256B or greater
• Mounting type: Surface Mount preferred for design continuity
• Package compatibility: Pin count and electrical interface alignment
• Feature set: Alarm, Leap Year, and Watchdog Timer support

The substitute parts listed below meet these criteria with varying package configurations and electrical specifications. Selection depends on specific application requirements for mounting technology, power consumption, and feature requirements.

Parameter Comparison

Engineering Selection Recommendations

DP8573AVX/NOPB (National Semiconductor)

• Active product status provides long-term supply assurance
• Surface mount package maintains design continuity with DS1501YS+
• Extended operating temperature range (-40°C ~ 85°C) exceeds original specification
• Significantly lower timekeeping current (1µA vs 5mA) reduces power consumption
• Package change from 28-SOIC to 28-LCC requires PCB layout modification
• Reduced feature set (Alarm, Leap Year only) may require design evaluation

M48T02-150PC1 (STMicroelectronics)

• Active product status with established supply chain
• Through-hole mounting requires PCB redesign from surface mount
• Timekeeper® series provides proven reliability
• Reduced feature set (Leap Year only) compared to original
• 24-pin DIP package differs from 28-pin original

M48T08-150PC1 (STMicroelectronics)

• Active product status with established supply chain
• Through-hole mounting requires PCB redesign from surface mount
• Timekeeper® series provides proven reliability
• Retains Watchdog Timer feature from original
• 28-pin DIP package maintains pin count but requires layout modification

M48T35AV-10MH1F (STMicroelectronics)

• Active product status with established supply chain
• Surface mount package maintains design continuity
• Timekeeper® series provides proven reliability
• Operates at lower voltage range (3V ~ 3.6V) requires power supply evaluation
• Reduced feature set (Leap Year only)
• SNAPHAT socket requirement adds assembly consideration

M48T37Y-70MH1F (STMicroelectronics)

• Active product status with established supply chain
• Surface mount package maintains design continuity
• Timekeeper® series provides proven reliability
• Retains Alarm and Watchdog Timer features
• 44-pin package increases pin count and requires PCB redesign
• SNAPHAT socket requirement adds assembly consideration

Frequently Asked Questions (FAQ)

Q: Can DS1501YS+ be directly replaced with DP8573AVX/NOPB without PCB modification? A: No. While both are 28-pin surface mount devices, the DS1501YS+ uses 28-SOIC packaging while DP8573AVX/NOPB uses 28-LCC (J-Lead) packaging. Pin pitch and footprint differ, requiring PCB layout modification. Electrical interface compatibility is maintained.

Q: Which substitute part best preserves the original feature set? A: M48T37Y-70MH1F retains Alarm and Watchdog Timer features from the DS1501YS+. However, it uses a 44-pin package versus the original 28-pin, requiring significant PCB redesign.

Q: Are the through-hole M48T02-150PC1 and M48T08-150PC1 suitable for surface mount applications? A: No. These parts require through-hole mounting technology. They are suitable only for designs that can accommodate DIP package mounting. M48T08-150PC1 maintains the 28-pin count but in DIP format.

Q: What is the impact of voltage range differences in M48T35AV-10MH1F? A: M48T35AV-10MH1F operates at 3V ~ 3.6V versus the original 4.5V ~ 5.5V. This requires evaluation of system power supply architecture. The part is not suitable for 5V-only systems without voltage regulation.

Q: Do all substitute parts support 24-hour time format? A: Yes. All substitute parts listed support HH:MM:SS 24-hour time format and YY-MM-DD-dd date format, maintaining compatibility with the original timekeeping protocol.

Q: What is the significance of SNAPHAT socket requirements in M48T35AV-10MH1F and M48T37Y-70MH1F? A: SNAPHAT sockets are specialized test and programming interfaces. Their requirement indicates these parts may need specific handling during manufacturing and programming phases. Standard surface mount assembly processes may require adapter tooling.

Q: Which substitute offers the lowest power consumption? A: DP8573AVX/NOPB provides the lowest timekeeping current at 1µA @ 5V, compared to 5mA for the original DS1501YS+. This represents a 5000x reduction in standby power consumption.

Q: Are all substitute parts RoHS3 compliant? A: M48T02-150PC1, M48T08-150PC1, M48T35AV-10MH1F, and M48T37Y-70MH1F are confirmed ROHS3 Compliant. DP8573AVX/NOPB compliance status is not specified in available documentation.