DS1685-3 Equivalent & Substitute Parts

Part Overview

The DS1685-3 is a Real Time Clock (RTC) IC with integrated Clock/Calendar functionality, manufactured by Analog Devices Inc./Maxim Integrated. This 24-DIP through-hole component provides 242 bytes of parallel interface memory with alarm, NVSRAM, square wave output, and Y2K compliance features. The DS1685-3 is classified as obsolete, making identification of functionally equivalent substitute parts essential for legacy system maintenance and new design implementations where through-hole packaging is required.

Substiute Parts

DS1685-3

Analog Devices Inc./Maxim IntegratedIn Stock: 1181DS1685-3 Datasheet

Current PartRFQ

DS1685-3+

Analog Devices Inc./Maxim IntegratedIn Stock: 2151DS1685-3+ Datasheet

DirectRFQ

DP8573AVX/NOPB

National SemiconductorIn Stock: 1484DP8573AVX/NOPB Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the DS1685-3 are identified based on the following critical parameters that determine functional compatibility:

Primary Substitution Criteria:

• Real Time Clock (RTC) with Clock/Calendar functionality
• Parallel interface architecture
• Time format support: HH:MM:SS (12/24 hr)
• Date format support: YY-MM-DD-dd
• Alarm and timekeeping features
• Non-volatile memory for calendar data

Substitute Classification:

1. Direct Pin-Compatible Substitute (DS1685-3+): Identical electrical specifications, memory size, interface, voltage ratings, and package footprint. Differs only in packaging format (Bulk vs. standard) and RoHS compliance status.

2. Functional Equivalent with Package Variation (DP8573AVX/NOPB): Provides equivalent RTC Clock/Calendar functionality with parallel interface and time/date format support. Differs in package type (28-LCC J-Lead surface mount vs. 24-DIP through-hole), voltage supply range (4.5V ~ 5.5V vs. 2.7V ~ 3.7V), and product status (Active vs. Obsolete).

Parameter Comparison

Engineering Selection Recommendations

DS1685-3+ Selection Criteria: Select DS1685-3+ when direct replacement within existing through-hole PCB layouts is required. This substitute maintains identical electrical specifications, memory capacity, and package dimensions. DS1685-3+ offers improved RoHS3 compliance status compared to the original DS1685-3, making it suitable for applications with environmental or regulatory compliance requirements. Both components share obsolete product status.

DP8573AVX/NOPB Selection Criteria: Select DP8573AVX/NOPB only when system design accommodates surface-mount 28-LCC packaging and supply voltage can be adjusted to 4.5V ~ 5.5V range. This substitute provides active product status, extended operating temperature range (-40°C ~ 85°C), and superior timekeeping current efficiency (1µA @ 5V). DP8573AVX/NOPB is suitable for new designs or legacy system redesigns where packaging transition is feasible. Direct PCB layout compatibility with DS1685-3 through-hole footprint is not possible without adapter solutions.

Frequently Asked Questions (FAQ)

Q: Can DS1685-3+ be used as a direct drop-in replacement for DS1685-3? A: Yes. DS1685-3+ maintains identical package dimensions (24-DIP, 0.600" spacing), electrical specifications (2.7V ~ 3.7V supply), memory size (242B), and parallel interface architecture. No circuit modifications are required for substitution.

Q: What are the key differences between DS1685-3 and DP8573AVX/NOPB? A: Primary differences include package type (24-DIP through-hole vs. 28-LCC surface mount), supply voltage range (2.7V ~ 3.7V vs. 4.5V ~ 5.5V), operating temperature range (0°C ~ 70°C vs. -40°C ~ 85°C), and product status (Obsolete vs. Active). DP8573AVX/NOPB requires PCB redesign and voltage regulation modifications.

Q: Is DP8573AVX/NOPB compatible with existing DS1685-3 PCB layouts? A: No. DP8573AVX/NOPB uses 28-LCC surface-mount packaging with different pin configuration and spacing. Direct substitution on through-hole PCBs designed for 24-DIP components is not possible without adapter circuitry or complete PCB redesign.

Q: Which substitute should be selected for new product designs? A: DP8573AVX/NOPB is recommended for new designs due to active product status and extended operating temperature range. DS1685-3+ is appropriate only for legacy system maintenance where through-hole packaging and 2.7V ~ 3.7V supply voltage are design constraints.

Q: Are there RoHS compliance differences between these substitutes? A: DS1685-3 is RoHS non-compliant, while DS1685-3+ is ROHS3 compliant. DP8573AVX/NOPB RoHS status is not specified in available documentation. Compliance requirements should be verified against specific application standards.

Q: What is the memory capacity difference between DS1685-3 and DP8573AVX/NOPB? A: DS1685-3 provides 242 bytes of memory. DP8573AVX/NOPB memory size is not specified in available technical data. Memory capacity should be confirmed with manufacturer documentation before substitution in applications with specific storage requirements.