DS1685EN-5/T&R Real Time Clock IC Equivalent & Substitute Parts

Part Overview

The DS1685EN-5/T&R is a Real Time Clock (RTC) IC with integrated Clock/Calendar functionality, manufactured by Analog Devices Inc./Maxim Integrated. This 24-TSSOP surface mount device provides 242 bytes of NVSRAM, alarm capability, square wave output, and Y2K compliance. The part is classified as obsolete, making equivalent and substitute parts necessary for ongoing system support and new design implementations. Substitute parts must maintain functional compatibility across clock/calendar operations, parallel interface architecture, and supply voltage specifications.

Substiute Parts

DS1685EN-5/T&R

Analog Devices Inc./Maxim IntegratedIn Stock: 1094DS1685EN-5/T&R Datasheet

Current PartRFQ

DS1685EN-5+T&R

Analog Devices Inc./Maxim IntegratedIn Stock: 978DS1685EN-5+T&R Datasheet

DirectRFQ

BQ3285S-SB2

Texas InstrumentsIn Stock: 1987BQ3285S-SB2 Datasheet

MFR RecommendedRFQ

BQ4802LYDWR

Texas InstrumentsIn Stock: 3828BQ4802LYDWR Datasheet

MFR RecommendedRFQ

DP8573AVX/NOPB

National SemiconductorIn Stock: 1484DP8573AVX/NOPB Datasheet

MFR RecommendedRFQ

M48T18-100PC1

STMicroelectronicsIn Stock: 1462M48T18-100PC1 Datasheet

MFR RecommendedRFQ

M48T35AV-10PC1

STMicroelectronicsIn Stock: 1390M48T35AV-10PC1 Datasheet

MFR RecommendedRFQ

M48T37V-10MH1F

STMicroelectronicsIn Stock: 1945M48T37V-10MH1F Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution logic for the DS1685EN-5/T&R is based on the following critical parameters:

Primary Compatibility Criteria:

• Parallel interface architecture
• Clock/Calendar functionality with HH:MM:SS (12/24 hr) and YY-MM-DD-dd date format support
• Supply voltage range: 4.5V ~ 5.5V (primary) and 2.5V ~ 3.7V (battery backup)
• Surface mount packaging
• Alarm and NVSRAM features

Substitution Categories:

Direct Equivalent (Packaging Variant): DS1685EN-5+T&R maintains identical electrical specifications and package type (24-TSSOP) with active product status and RoHS3 compliance.

Functional Equivalents (Different Packages): BQ3285S-SB2, BQ4802LYDWR, DP8573AVX/NOPB, and M48T18-100PC1 provide clock/calendar functionality with parallel interface and compatible supply voltage ranges. These parts differ in package type (24-SOIC, 28-SOIC, 28-LCC, 28-DIP) and feature sets, requiring PCB layout and design modifications.

Extended Compatibility (Voltage Variants): M48T35AV-10PC1 and M48T37V-10MH1F operate at 3V ~ 3.6V supply voltage, suitable for low-power applications but requiring design verification for 5V primary supply compatibility.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Identical Functionality): DS1685EN-5+T&R is the primary direct equivalent, offering identical electrical specifications, 24-TSSOP packaging, and active product status. This part is RoHS3 compliant, addressing environmental compliance requirements where the original DS1685EN-5/T&R is non-compliant.

For 5V Supply Applications with Package Flexibility: BQ3285S-SB2 (Texas Instruments, 24-SOIC) and DP8573AVX/NOPB (National Semiconductor, 28-LCC) maintain 4.5V ~ 5.5V supply voltage compatibility and extended temperature range (-40°C ~ 85°C for DP8573AVX/NOPB). Both are RoHS3 compliant and active products. PCB layout modifications are required due to different package footprints.

For Low-Power or 3V Applications: BQ4802LYDWR operates at 2.7V ~ 3.6V supply voltage with lower timekeeping current (1.5mA typical @ 2.7V ~ 3.6V). This part includes supervisor and watchdog timer features but requires design verification for systems requiring 5V primary supply operation.

For Through-Hole Mounting: M48T18-100PC1 (STMicroelectronics, 28-DIP Module) provides parallel clock/calendar functionality in through-hole packaging. This part is suitable for legacy board designs or applications requiring through-hole component mounting. RoHS3 compliance and active product status are confirmed.

Compliance Considerations: All recommended substitutes except DP8573AVX/NOPB are confirmed RoHS3 compliant. For applications requiring environmental compliance certification, DS1685EN-5+T&R, BQ3285S-SB2, BQ4802LYDWR, and M48T18-100PC1 are preferred selections.

Frequently Asked Questions (FAQ)

Q: Can DS1685EN-5+T&R be used as a direct replacement for DS1685EN-5/T&R? A: Yes. DS1685EN-5+T&R is electrically and functionally identical to DS1685EN-5/T&R, with the same 24-TSSOP package, supply voltage range (4.5V ~ 5.5V), battery backup voltage (2.5V ~ 3.7V), and feature set (Alarm, NVSRAM, Square Wave Output, Y2K). The primary difference is active product status and RoHS3 compliance. No design modifications are required.

Q: What are the key differences between BQ3285S-SB2 and the original DS1685EN-5/T&R? A: BQ3285S-SB2 maintains parallel interface, clock/calendar functionality, and 4.5V ~ 5.5V supply voltage compatibility. Differences include: package type (24-SOIC vs. 24-TSSOP), reduced memory (114B vs. 242B), operating temperature range (0°C ~ 70°C vs. -40°C ~ 85°C), and additional features (Daylight Savings, Leap Year). PCB layout modification is required due to different package footprint.

Q: Is BQ4802LYDWR suitable for 5V applications? A: BQ4802LYDWR operates at 2.7V ~ 3.6V primary supply voltage, not 5V. This part is designed for low-power applications. For 5V primary supply systems, use DS1685EN-5+T&R, BQ3285S-SB2, DP8573AVX/NOPB, or M48T18-100PC1 instead.

Q: What mounting type changes are required when switching from DS1685EN-5/T&R to M48T18-100PC1? A: DS1685EN-5/T&R is surface mount (24-TSSOP), while M48T18-100PC1 is through-hole (28-DIP Module). This requires PCB redesign to accommodate through-hole mounting holes and different pin layout. Use this substitute only when through-hole mounting is required or preferred.

Q: Are all substitute parts RoHS3 compliant? A: DS1685EN-5+T&R, BQ3285S-SB2, BQ4802LYDWR, and M48T18-100PC1 are confirmed RoHS3 compliant. DP8573AVX/NOPB RoHS status is not specified in available documentation. For applications requiring RoHS3 certification, confirm compliance with the component supplier.

Q: What is the memory capacity difference between DS1685EN-5/T&R and BQ3285S-SB2? A: DS1685EN-5/T&R provides 242 bytes of NVSRAM, while BQ3285S-SB2 provides 114 bytes. If the application requires the full 242-byte memory capacity, use DS1685EN-5+T&R or verify that BQ3285S-SB2's reduced memory meets system requirements.

Q: Can DP8573AVX/NOPB replace DS1685EN-5/T&R in extended temperature applications? A: Yes, for operating temperature range. DP8573AVX/NOPB supports -40°C ~ 85°C, matching the original part. However, the 28-LCC (J-Lead) package differs from 24-TSSOP, requiring PCB layout modification. Battery backup voltage range (2.2V ~ 5.1V) is broader than the original (2.5V ~ 3.7V).