DS12885S/T&R Real Time Clock IC Equivalent & Substitute Parts

Part Overview

The DS12885S/T&R is a Real Time Clock (RTC) IC with integrated Clock/Calendar functionality manufactured by Analog Devices Inc./Maxim Integrated. This device provides 114 bytes of NVSRAM with parallel interface, supporting 12/24-hour time format and YY-MM-DD-dd date format. The part is classified as obsolete, making equivalent and substitute parts necessary for ongoing system support and new design implementations. Substitute parts are selected based on matching electrical specifications, interface compatibility, and package form factors.

Substiute Parts

DS12885S/T&R

Analog Devices Inc./Maxim IntegratedIn Stock: 799DS12885S/T&R Datasheet

Current PartRFQ

DS12885S+T&R

Analog Devices Inc./Maxim IntegratedIn Stock: 2639DS12885S+T&R Datasheet

DirectRFQ

BQ3285S-SB2

Texas InstrumentsIn Stock: 1987BQ3285S-SB2 Datasheet

DirectRFQ

BQ4802LYDW

Texas InstrumentsIn Stock: 1993BQ4802LYDW Datasheet

MFR RecommendedRFQ

BQ4802YDW

BenchmarqIn Stock: 1824BQ4802YDW Datasheet

MFR RecommendedRFQ

M48T35Y-70MH1F

STMicroelectronicsIn Stock: 1491M48T35Y-70MH1F Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the DS12885S/T&R are categorized based on the following substitution criteria:

Direct Equivalents (Same Package, Same Voltage Domain):

• DS12885S+T&R: Identical base product with Tape & Reel packaging. Maintains 24-SOIC package, 4.5V ~ 5.5V supply voltage, and all core RTC features. Product status is Active, providing long-term availability.
• BQ3285S-SB2: Texas Instruments equivalent with matching 24-SOIC package and identical electrical specifications (4.5V ~ 5.5V supply, 0°C ~ 70°C operating range, parallel interface, 114B memory). Tube packaging differs from original.

Functional Alternatives (Different Package, Different Voltage Domain):

• BQ4802LYDW: 28-SOIC package with reduced supply voltage range (2.7V ~ 3.6V). Includes additional features (Supervisor, Watchdog Timer) but operates in lower voltage domain. Requires design verification for voltage compatibility.
• BQ4802YDW: 28-SOIC package variant with 4.5V ~ 5.5V supply voltage matching original. Includes Supervisor and Watchdog Timer features. Benchmarq manufacturer source.
• M48T35Y-70MH1F: 28-SOP package with SNAPHAT Sockets. STMicroelectronics Timekeeper® series. Maintains 4.5V ~ 5.5V supply voltage but differs in package form factor and feature set (Leap Year only, no Alarm or Daylight Savings).

Key Parameters Determining Substitution:

• Package / Case form factor
• Supply voltage range (4.5V ~ 5.5V vs. 2.7V ~ 3.6V)
• Parallel interface compatibility
• Memory size and NVSRAM availability
• Operating temperature range (0°C ~ 70°C)
• RoHS3 compliance and MSL rating

Parameter Comparison

Engineering Selection Recommendations

For Direct Pin-Compatible Replacement: Select DS12885S+T&R or BQ3285S-SB2. Both maintain the 24-SOIC package footprint and 4.5V ~ 5.5V supply voltage range. DS12885S+T&R is the preferred choice due to Active product status and identical feature set. BQ3285S-SB2 provides Texas Instruments sourcing as an alternative with equivalent electrical performance.

For New Designs Requiring Extended Features: BQ4802LYDW and BQ4802YDW offer integrated Supervisor and Watchdog Timer functionality. BQ4802YDW maintains 4.5V ~ 5.5V supply voltage compatibility with existing 5V systems. BQ4802LYDW operates at reduced voltage (2.7V ~ 3.6V) and is suitable for low-power applications. Both require PCB layout modifications due to 28-SOIC package.

For Alternative Package Implementations: M48T35Y-70MH1F provides 28-SOP package with SNAPHAT Sockets from STMicroelectronics Timekeeper® series. This option requires significant PCB redesign and is suitable only when package form factor is a design requirement. Time format is limited to 24-hour operation.

Compliance Considerations: All recommended substitutes maintain ROHS3 compliance and MSL 1 rating (unlimited moisture sensitivity). Verify RoHS status with supplier for BQ4802YDW before procurement.

Frequently Asked Questions (FAQ)

Q: Can DS12885S+T&R directly replace DS12885S/T&R? A: Yes. DS12885S+T&R is the direct equivalent with identical electrical specifications, package form factor (24-SOIC), and feature set. The primary difference is packaging format (Tape & Reel vs. standard packaging) and Active product status, ensuring long-term availability.

Q: What is the key difference between BQ3285S-SB2 and the original DS12885S/T&R? A: BQ3285S-SB2 is electrically equivalent with matching 24-SOIC package and 4.5V ~ 5.5V supply voltage. The difference is manufacturer (Texas Instruments vs. Analog Devices) and packaging format (Tube vs. original). Functional performance is identical for parallel RTC applications.

Q: Why do BQ4802LYDW and BQ4802YDW require design verification? A: Both parts use 28-SOIC package instead of 24-SOIC, requiring PCB layout modifications. BQ4802LYDW operates at 2.7V ~ 3.6V (lower voltage domain), necessitating power supply circuit changes. BQ4802YDW maintains 4.5V ~ 5.5V compatibility but still requires package-level redesign.

Q: Is M48T35Y-70MH1F suitable as a direct replacement? A: No. M48T35Y-70MH1F uses 28-SOP package with SNAPHAT Sockets, requiring significant PCB redesign. Time format is limited to 24-hour operation (no 12-hour mode). This option is suitable only for new designs where package form factor is a specific requirement.

Q: What are the supply voltage considerations when selecting a substitute? A: The original DS12885S/T&R operates at 4.5V ~ 5.5V. Direct replacements (DS12885S+T&R, BQ3285S-SB2) maintain this voltage range. BQ4802LYDW operates at 2.7V ~ 3.6V and requires power supply redesign. BQ4802YDW maintains 4.5V ~ 5.5V compatibility. Verify system voltage requirements before selection.

Q: Are all substitute parts RoHS3 compliant? A: DS12885S+T&R, BQ3285S-SB2, BQ4802LYDW, and M48T35Y-70MH1F are confirmed ROHS3 compliant. BQ4802YDW RoHS status is not specified in available data. Confirm RoHS compliance with supplier documentation before procurement.

Q: What is the MSL (Moisture Sensitivity Level) rating for these parts? A: DS12885S/T&R, DS12885S+T&R, BQ3285S-SB2, and BQ4802LYDW are rated MSL 1 (Unlimited). M48T35Y-70MH1F is rated MSL 3 (168 Hours), requiring controlled storage and handling procedures. BQ4802YDW MSL rating is not specified.