DS1685QN-5 Real Time Clock IC - Equivalent & Substitute Parts

Part Overview

The DS1685QN-5 is a Real Time Clock (RTC) IC with integrated Clock/Calendar functionality, 242 bytes of NVSRAM, and parallel interface. Manufactured by Analog Devices Inc./Maxim Integrated, this component operates across -40°C to 85°C with dual power supply support (main: 4.5V–5.5V, battery: 2.5V–3.7V). The part is classified as obsolete, making equivalent substitutes necessary for new designs and legacy system maintenance. Substitute parts must maintain functional equivalence in timekeeping accuracy, memory capacity, alarm capability, and interface protocol while accommodating modern compliance requirements.

Substiute Parts

DS1685QN-5

Analog Devices Inc./Maxim IntegratedIn Stock: 1110DS1685QN-5 Datasheet

Current PartRFQ

DS1685QN-5+

Analog Devices Inc./Maxim IntegratedIn Stock: 780DS1685QN-5+ Datasheet

DirectRFQ

M48T02-70PC1

STMicroelectronicsIn Stock: 1276M48T02-70PC1 Datasheet

MFR RecommendedRFQ

M48T12-70PC1

STMicroelectronicsIn Stock: 2150M48T12-70PC1 Datasheet

MFR RecommendedRFQ

M48T37V-10MH1F

STMicroelectronicsIn Stock: 1945M48T37V-10MH1F Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility is determined by strict alignment across the following critical parameters:

• Interface Type: Parallel interface required for direct pin compatibility
• Memory Capacity: 242 bytes NVSRAM for data storage equivalence
• Time/Date Format: HH:MM:SS (12/24 hr) and YY-MM-DD-dd format support
• Core Features: Alarm and NVSRAM functionality
• Supply Voltage Range: Compatibility with 4.5V–5.5V main supply and battery backup capability
• Operating Temperature Range: Support for -40°C to 85°C operational envelope
• Package Type: Physical form factor and pin count

The DS1685QN-5+ represents a direct form, fit, and function equivalent with improved compliance status. The STMicroelectronics M48T02-70PC1, M48T12-70PC1, and M48T37V-10MH1F are manufacturer-recommended alternatives that maintain core RTC/Calendar functionality with parallel interface but may require design accommodation for package differences and operating temperature ranges.

Parameter Comparison

Engineering Selection Recommendations

DS1685QN-5+ (Direct Equivalent) Select this part for direct replacement in existing designs. Maintains identical electrical specifications, package form factor, and pin configuration as the original DS1685QN-5. Achieves ROHS3 compliance, addressing modern regulatory requirements while preserving full backward compatibility.

M48T12-70PC1 (Functional Equivalent - Through Hole) Suitable for applications where through-hole mounting is preferred or required. Maintains parallel interface, 24-hour time format, and YY-MM-DD-dd date format. Operates across 4.5V–5.5V supply range matching the original specification. Requires PCB redesign to accommodate 24-DIP Module package. ROHS3 compliant and actively manufactured.

M48T02-70PC1 (Functional Equivalent - Through Hole) Alternative through-hole option with identical package footprint to M48T12-70PC1. Operates across 4.75V–5.5V supply range (narrower than original). Includes leap year support. Requires PCB redesign. ROHS3 compliant and actively manufactured.

M48T37V-10MH1F (Functional Equivalent - Low Voltage Surface Mount) Designed for 3V–3.6V supply operation, suitable for battery-powered or low-voltage applications. Maintains surface mount form factor. Includes alarm and watchdog timer features. Operating temperature range limited to 0°C–70°C (narrower than original -40°C–85°C). Requires design accommodation for 44-BSOP package and SNAPHAT requirement. ROHS3 compliant and actively manufactured.

Frequently Asked Questions (FAQ)

Q: Can DS1685QN-5+ be used as a direct drop-in replacement for DS1685QN-5? A: Yes. The DS1685QN-5+ maintains identical electrical specifications, package dimensions, pin configuration, and functional features. The primary difference is active product status and ROHS3 compliance.

Q: What are the key differences between the Analog Devices and STMicroelectronics options? A: Analog Devices parts (DS1685QN-5+) maintain the original 28-LCC surface mount package and -40°C to 85°C operating range. STMicroelectronics Timekeeper® series parts offer different package options (24-DIP through-hole or 44-BSOP surface mount) and narrower operating temperature ranges (0°C–70°C). All maintain parallel interface and core RTC/Calendar functionality.

Q: Can M48T02-70PC1 or M48T12-70PC1 replace DS1685QN-5 in existing designs? A: Functional replacement is possible but requires PCB redesign. Both parts use 24-DIP Module through-hole packages versus the original 28-LCC surface mount. Electrical specifications are compatible (parallel interface, 24-hour time format, YY-MM-DD-dd date format, 4.5V–5.5V supply). Operating temperature range is limited to 0°C–70°C.

Q: Is M48T37V-10MH1F suitable for high-temperature applications? A: No. This part operates only across 0°C–70°C, which is narrower than the original DS1685QN-5 specification of -40°C–85°C. It is suitable for standard industrial and commercial temperature ranges but not extended temperature applications.

Q: What compliance certifications apply to substitute parts? A: DS1685QN-5+ and all STMicroelectronics alternatives (M48T02-70PC1, M48T12-70PC1, M48T37V-10MH1F) are ROHS3 compliant. All parts are REACH unaffected and classified under ECCN EAR99 with HTSUS code 8542.39.0001.

Q: Which substitute part requires additional mechanical accommodation? A: M48T37V-10MH1F requires SNAPHAT mechanical support for the 44-BSOP package. M48T02-70PC1 and M48T12-70PC1 require PCB redesign for 24-DIP Module footprint and through-hole mounting.