DS1685SN-3+ Real Time Clock IC Equivalent & Substitute Parts

Part Overview

The DS1685SN-3+ is a Real Time Clock (RTC) IC with integrated Clock/Calendar functionality, manufactured by Analog Devices Inc./Maxim Integrated. This device provides parallel interface timekeeping with 242 bytes of NVSRAM, alarm capability, and square wave output generation. The part is currently in active production status with full RoHS3 compliance and unlimited moisture sensitivity rating (MSL 1). Alternative equivalent parts are identified based on matching electrical specifications, package configuration, and functional feature sets.

Substiute Parts

DS1685SN-3+

Analog Devices Inc./Maxim IntegratedIn Stock: 1156DS1685SN-3+ Datasheet

Current PartRFQ

DS1685SN-3+

Analog Devices Inc./Maxim IntegratedIn Stock: 1156DS1685SN-3+ Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the DS1685SN-3+ is determined by strict equivalence across the following critical parameters:

Electrical Compatibility Requirements:

• Supply voltage range: 2.7V ~ 3.7V
• Battery backup voltage range: 2.5V ~ 3.7V
• Timekeeping current specification: 2mA @ 3V maximum
• Operating temperature range: -40°C ~ 85°C

Functional Requirements:

• RTC Clock/Calendar functionality with parallel interface
• Memory capacity: 242 bytes NVSRAM
• Time format: HH:MM:SS with 12/24 hour selection
• Date format: YY-MM-DD-dd
• Feature set: Alarm, NVSRAM, Square Wave Output, Y2K support

Package & Mechanical Requirements:

• Package type: 24-SOIC (0.295", 7.50mm Width)
• Mounting type: Surface Mount
• Pin configuration and footprint compatibility

Compliance & Regulatory Requirements:

• RoHS3 compliance
• Moisture Sensitivity Level 1 (Unlimited)
• Active product status

Only parts meeting all specified parameters across these categories qualify as direct substitutes.

Parameter Comparison

Engineering Selection Recommendations

The DS1685SN-3+ is an active production component with full RoHS3 compliance and unlimited moisture sensitivity rating. Component selection should be based on the following engineering criteria:

Product Status Verification: Confirm active production status with the manufacturer or authorized distributor to ensure long-term availability and supply chain continuity.

Compliance Certification: Verify RoHS3 compliance documentation for applications subject to EU Directive 2011/65/EU or equivalent regional regulations. The DS1685SN-3+ meets these requirements.

Package Footprint Validation: Confirm PCB layout compatibility with the 24-SOIC (0.295", 7.50mm Width) package specification. Surface mount assembly equipment must support this package type.

Voltage Supply Specifications: Verify that system power supply design delivers stable voltage within the 2.7V ~ 3.7V operating range and 2.5V ~ 3.7V battery backup range.

Temperature Operating Range: Confirm that the application environment remains within the -40°C ~ 85°C operating temperature specification.

Functional Feature Compatibility: Ensure that the application design utilizes or accommodates the integrated features: parallel interface, alarm functionality, NVSRAM storage, square wave output, and Y2K support.

Frequently Asked Questions (FAQ)

Q: What makes a part a direct substitute for the DS1685SN-3+?

A: A direct substitute must match all electrical specifications (supply voltage, battery voltage, timekeeping current), functional features (RTC Clock/Calendar with parallel interface, 242-byte NVSRAM, alarm, square wave output, Y2K support), package configuration (24-SOIC 0.295" width), and compliance certifications (RoHS3, MSL 1). Any deviation in these parameters disqualifies a part from direct substitution.

Q: Can I use a different package type if the electrical specifications match?

A: No. Package type is a critical substitution parameter. The DS1685SN-3+ requires 24-SOIC (0.295", 7.50mm Width) surface mount configuration. Different package types have incompatible footprints and cannot be used as direct substitutes without PCB redesign.

Q: What is the significance of the 242-byte NVSRAM specification?

A: The 242-byte NVSRAM (Non-Volatile Static RAM) provides persistent storage for user data and calendar information. This memory capacity is a functional requirement for the DS1685SN-3+. Substitute parts must provide identical memory size and non-volatile storage capability.

Q: Does the DS1685SN-3+ support both 12-hour and 24-hour time formats?

A: Yes. The device supports selectable time format operation: HH:MM:SS in either 12-hour or 24-hour mode. This flexibility is a standard feature of the DS1685SN-3+ and must be present in any substitute part.

Q: What is the difference between supply voltage and battery voltage specifications?

A: Supply voltage (2.7V ~ 3.7V) powers normal device operation. Battery voltage (2.5V ~ 3.7V) powers the timekeeping function during main power loss. The battery voltage range is slightly lower to accommodate typical battery discharge characteristics. Both ranges must be supported by substitute parts.

Q: Is the DS1685SN-3+ suitable for industrial temperature applications?

A: The operating temperature range is -40°C ~ 85°C, which covers industrial temperature specifications. Applications requiring extended temperature ranges beyond this specification require alternative components.

Q: What does RoHS3 compliance mean for this component?

A: RoHS3 compliance indicates conformance to EU Directive 2011/65/EU (as amended by Directive 2015/863/EU), which restricts hazardous substances in electrical and electronic equipment. The DS1685SN-3+ meets these restrictions and is suitable for applications subject to RoHS regulations.

Q: What is Moisture Sensitivity Level 1 (MSL 1)?

A: MSL 1 indicates unlimited floor life. The component has no moisture sensitivity restrictions and does not require special storage or handling conditions related to humidity exposure. This is the least restrictive moisture sensitivity classification.