DS1685EN-5 Real Time Clock IC - Equivalent & Substitute Parts

Part Overview

The DS1685EN-5 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 connectivity, and features including alarm capability, square wave output, and Y2K compliance. The DS1685EN-5 is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. Active alternatives with compatible electrical and mechanical specifications are available from multiple manufacturers.

Substiute Parts

DS1685EN-5

Analog Devices Inc./Maxim IntegratedIn Stock: 2158DS1685EN-5 Datasheet

Current PartRFQ

DS1685EN-5+

Analog Devices Inc./Maxim IntegratedIn Stock: 5272DS1685EN-5+ Datasheet

DirectRFQ

BQ4802LYPW

Texas InstrumentsIn Stock: 9564BQ4802LYPW Datasheet

MFR RecommendedRFQ

M48T08-150PC1

STMicroelectronicsIn Stock: 1658M48T08-150PC1 Datasheet

MFR RecommendedRFQ

M48T201V-85MH1F

STMicroelectronicsIn Stock: 1609M48T201V-85MH1F Datasheet

MFR RecommendedRFQ

M48T35Y-70MH1F

STMicroelectronicsIn Stock: 1491M48T35Y-70MH1F Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the DS1685EN-5 is determined by the following critical parameters:

Primary Compatibility Criteria:

• Interface type: Parallel
• Time format support: HH:MM:SS (12/24 hr)
• Date format support: YY-MM-DD-dd
• Mounting type: Surface Mount
• Package compatibility: 24-TSSOP or equivalent pin-compatible packages

Secondary Compatibility Criteria:

• Voltage supply range overlap with 4.5V ~ 5.5V
• Operating temperature range that encompasses or exceeds -40°C ~ 85°C
• Features: Alarm and Y2K support preferred for functional equivalence

Substitute parts are grouped into two categories:

Direct Equivalents (Identical Package & Electrical Specifications):

• DS1685EN-5+ (Analog Devices Inc./Maxim Integrated): Identical specifications with active product status and improved RoHS3 compliance

Functional Alternatives (Different Package, Compatible Electrical Interface):

• BQ4802LYPW (Texas Instruments): 28-TSSOP package with parallel interface and compatible time/date formats; operates at lower voltage range (2.7V ~ 3.6V)
• M48T35Y-70MH1F (STMicroelectronics): 28-SOP package with parallel interface; operates at 4.5V ~ 5.5V supply range
• M48T201V-85MH1F (STMicroelectronics): 44-BSOP package with parallel interface; operates at 3V ~ 3.6V supply range
• M48T08-150PC1 (STMicroelectronics): 28-DIP through-hole package with parallel interface; operates at 4.75V ~ 5.5V supply range

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Identical Package and Electrical Specifications):

DS1685EN-5+ is the primary recommendation. This part maintains identical electrical specifications, package form factor, and feature set as the obsolete DS1685EN-5. The DS1685EN-5+ is active in production and carries ROHS3 compliance certification, addressing regulatory requirements for new designs while preserving PCB layout and firmware compatibility.

For Alternative Designs (Different Package Accommodation Required):

Selection among alternative parts depends on system voltage requirements and thermal operating range:

• M48T35Y-70MH1F is suitable for systems operating at 4.5V ~ 5.5V supply voltage with operating temperature range limited to 0°C ~ 70°C. This STMicroelectronics Timekeeper® device maintains the same supply voltage as the original DS1685EN-5 and provides ROHS3 compliance. Package change from 24-TSSOP to 28-SOP requires PCB redesign.

• M48T08-150PC1 accommodates through-hole mounting requirements where surface-mount technology is not feasible. Operating voltage range 4.75V ~ 5.5V and temperature range 0°C ~ 70°C align with standard industrial specifications. This part is ROHS3 compliant and carries the Timekeeper® series designation.

• BQ4802LYPW operates at reduced voltage range (2.7V ~ 3.6V) and is suitable for low-power applications. Operating temperature range is limited to 0°C ~ 70°C. This Texas Instruments device provides lower timekeeping current consumption (1.5mA typical) and includes additional features such as daylight savings and watchdog timer functionality.

• M48T201V-85MH1F operates at 3V ~ 3.6V supply voltage and provides the highest pin count (44-BSOP) with expanded feature set including supervisor and watchdog timer. This part is suitable for systems requiring enhanced monitoring capabilities. Operating temperature range is 0°C ~ 70°C.

All substitute parts carry ROHS3 compliance and REACH unaffected status, meeting current regulatory requirements for component procurement.

Frequently Asked Questions (FAQ)

Q: Can DS1685EN-5+ be used as a direct replacement for DS1685EN-5?

A: Yes. DS1685EN-5+ maintains identical electrical specifications, package form factor (24-TSSOP), supply voltage range (4.5V ~ 5.5V), operating temperature range (-40°C ~ 85°C), and feature set. The primary difference is product status (active vs. obsolete) and improved RoHS compliance. No PCB or firmware modifications are required.

Q: What are the key differences between the DS1685EN-5 and BQ4802LYPW?

A: BQ4802LYPW differs in three critical areas: (1) Package: 28-TSSOP vs. 24-TSSOP, requiring PCB redesign; (2) Supply voltage: 2.7V ~ 3.6V vs. 4.5V ~ 5.5V, necessitating power supply compatibility verification; (3) Operating temperature: 0°C ~ 70°C vs. -40°C ~ 85°C, limiting use in extended temperature applications. BQ4802LYPW includes additional features (daylight savings, watchdog timer) not present in DS1685EN-5.

Q: Why do some substitute parts have different operating temperature ranges?

A: Operating temperature range is a fundamental design specification determined by the manufacturer's process technology and component qualification testing. The DS1685EN-5 operates from -40°C ~ 85°C (industrial extended range), while most substitute parts operate from 0°C ~ 70°C (commercial range). Selection must match the target application's thermal environment. Applications requiring -40°C ~ 85°C operation should prioritize DS1685EN-5+ or verify that alternative parts meet specific temperature requirements through design validation.

Q: Can M48T08-150PC1 replace DS1685EN-5 in a surface-mount assembly?

A: No. M48T08-150PC1 uses through-hole mounting (28-DIP package) while DS1685EN-5 uses surface-mount technology (24-TSSOP). Through-hole components require different PCB footprints, assembly processes, and board layout considerations. This part is suitable only for designs where through-hole mounting is specified or preferred.

Q: What is the significance of the 24-TSSOP vs. 28-TSSOP package difference?

A: Package differences indicate different pin counts and pinout configurations. 24-TSSOP has 24 pins while 28-TSSOP has 28 pins. These are not pin-compatible; each requires a unique PCB footprint and connector design. Substitution between these packages requires complete PCB redesign and firmware verification to ensure correct signal routing and functionality.

Q: Are all substitute parts RoHS compliant?

A: Yes. All listed substitute parts carry ROHS3 compliance certification. The original DS1685EN-5 is RoHS non-compliant. For new designs and procurement requiring RoHS compliance, DS1685EN-5+ or any of the alternative parts satisfy regulatory requirements.

Q: Which substitute part has the lowest power consumption?

A: BQ4802LYPW provides the lowest timekeeping current consumption at 1.5mA typical (measured at 2.7V ~ 3.6V). This is lower than DS1685EN-5 (3mA @ 5V), M48T35Y-70MH1F (2mA @ 4.75V ~ 5.5V), and M48T201V-85MH1F (2mA @ 3V ~ 3.6V). Selection for low-power applications must account for the reduced operating voltage range and temperature specifications.

Q: Can substitute parts with 3V supply voltage operate in a 5V system?

A: No. Parts specified for 3V ~ 3.6V supply voltage (M48T201V-85MH1F) or 2.7V ~ 3.6V (BQ4802LYPW) cannot be directly connected to 5V supply rails without voltage regulation. Operating these parts at voltages outside their specified range will cause component damage or malfunction. System power supply architecture must be verified to provide appropriate voltage levels for the selected substitute part.