DS1685EN-3 Real Time Clock IC Equivalent & Substitute Parts

Part Overview

The DS1685EN-3 is a Real Time Clock (RTC) IC with integrated Clock/Calendar functionality, manufactured by Analog Devices Inc./Maxim Integrated. This device provides 242 bytes of NVSRAM, parallel interface, and features including alarm capability, square wave output, and Y2K compliance. The DS1685EN-3 is classified as obsolete, making identification of active equivalent and substitute parts essential for ongoing system support and new design implementations.

Substiute Parts

DS1685EN-3

Analog Devices Inc./Maxim IntegratedIn Stock: 2371DS1685EN-3 Datasheet

Current PartRFQ

DS1685EN-3+

Analog Devices Inc./Maxim IntegratedIn Stock: 2562DS1685EN-3+ Datasheet

DirectRFQ

BQ4802YDW

BenchmarqIn Stock: 1824BQ4802YDW Datasheet

MFR RecommendedRFQ

M48T12-150PC1

STMicroelectronicsIn Stock: 2537M48T12-150PC1 Datasheet

MFR RecommendedRFQ

M48T58-70PC1

STMicroelectronicsIn Stock: 1546M48T58-70PC1 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the DS1685EN-3 is determined by the following critical parameters:

Primary Substitution Criteria:

• Interface type (Parallel)
• Package form factor and mounting type
• Supply voltage range compatibility
• Memory capacity and NVSRAM functionality
• Time and date format support (HH:MM:SS, YY-MM-DD-dd)
• Operating temperature range

Substitution Categories:

Category 1: Direct Manufacturer Equivalent (Same Package, Same Voltage) DS1685EN-3+ is the direct active equivalent from the same manufacturer. This part maintains identical electrical specifications, package type (24-TSSOP), supply voltage (2.7V ~ 3.7V), and functional features. The primary difference is product status (Active vs. Obsolete) and RoHS compliance (ROHS3 Compliant vs. non-compliant).

Category 2: Manufacturer-Recommended Alternatives (Different Package, Different Voltage) BQ4802YDW (Benchmarq), M48T12-150PC1 (STMicroelectronics), and M48T58-70PC1 (STMicroelectronics) are listed as manufacturer-recommended substitutes. These parts share the parallel interface and Clock/Calendar functionality but differ in package type, mounting method, and supply voltage requirements. These substitutes require board-level design modifications due to package incompatibility.

Parameter Comparison

Engineering Selection Recommendations

For Direct Pin-Compatible Replacement: DS1685EN-3+ is the appropriate selection for direct substitution. This part maintains identical package geometry (24-TSSOP), electrical specifications, and functional features. The transition from obsolete to active product status ensures long-term availability. ROHS3 compliance of DS1685EN-3+ addresses regulatory requirements where RoHS non-compliance of the original DS1685EN-3 may present supply chain or certification constraints.

For System-Level Redesign: BQ4802YDW, M48T12-150PC1, and M48T58-70PC1 are suitable alternatives when board-level modifications are acceptable. Selection among these three depends on:

• Voltage supply architecture: BQ4802YDW and M48T12-150PC1 operate at 4.5V ~ 5.5V; M48T58-70PC1 operates at 4.75V ~ 5.5V
• Mounting preference: BQ4802YDW remains surface mount (28-SOIC); M48T12-150PC1 and M48T58-70PC1 are through-hole (24-DIP and 28-DIP respectively)
• Operating temperature requirements: All three alternatives support 0°C ~ 70°C, which is narrower than the DS1685EN-3 range of -40°C ~ 85°C

All substitute parts maintain parallel interface architecture and support required time/date formats. ROHS3 compliance is confirmed for M48T12-150PC1 and M48T58-70PC1.

Frequently Asked Questions (FAQ)

Q: Can DS1685EN-3+ be used as a direct replacement for DS1685EN-3? A: Yes. DS1685EN-3+ is the active equivalent from the same manufacturer with identical package (24-TSSOP), pinout, supply voltage (2.7V ~ 3.7V), and functional specifications. No circuit modifications are required.

Q: What is the primary difference between DS1685EN-3 and DS1685EN-3+? A: Product status and RoHS compliance. DS1685EN-3 is obsolete and RoHS non-compliant; DS1685EN-3+ is active and ROHS3 compliant. Electrical and functional performance are identical.

Q: Can BQ4802YDW replace DS1685EN-3 without board modifications? A: No. BQ4802YDW uses a different package (28-SOIC vs. 24-TSSOP) and requires higher supply voltage (4.5V ~ 5.5V vs. 2.7V ~ 3.7V). Board-level redesign is necessary.

Q: What are the key differences between M48T12-150PC1 and M48T58-70PC1? A: Both are through-hole DIP packages from STMicroelectronics. M48T12-150PC1 is 24-DIP; M48T58-70PC1 is 28-DIP. Both operate at similar voltage ranges (4.5V ~ 5.5V and 4.75V ~ 5.5V respectively) and support identical time/date formats.

Q: Are the STMicroelectronics alternatives suitable for low-temperature applications? A: No. M48T12-150PC1 and M48T58-70PC1 support 0°C ~ 70°C operating temperature, which does not cover the extended low-temperature range (-40°C) of the DS1685EN-3. For applications requiring -40°C operation, DS1685EN-3+ is the appropriate selection.

Q: What supply voltage considerations apply when selecting a substitute? A: DS1685EN-3 and DS1685EN-3+ operate at 2.7V ~ 3.7V (low voltage). BQ4802YDW, M48T12-150PC1, and M48T58-70PC1 require 4.5V ~ 5.5V (standard logic voltage). System power architecture must support the selected part's voltage requirements.

Q: Are all substitute parts REACH compliant? A: Yes. DS1685EN-3, DS1685EN-3+, M48T12-150PC1, and M48T58-70PC1 are all listed as REACH Unaffected.