DS12885SN Real Time Clock IC Equivalent & Substitute Parts

Part Overview

The DS12885SN 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 parallel interface memory with alarm, daylight savings, leap year, and non-volatile SRAM capabilities in a 24-SOIC surface mount package. The DS12885SN is classified as obsolete, making identification of functionally equivalent substitute parts essential for ongoing system support, design updates, and production continuity.

Substiute Parts

DS12885SN

Analog Devices Inc./Maxim IntegratedIn Stock: 1128DS12885SN Datasheet

Current PartRFQ

DS12885SN+

Analog Devices Inc./Maxim IntegratedIn Stock: 2142DS12885SN+ Datasheet

DirectRFQ

BQ3285S-SB2

Texas InstrumentsIn Stock: 1987BQ3285S-SB2 Datasheet

MFR RecommendedRFQ

BQ4802LYDWR

Texas InstrumentsIn Stock: 3828BQ4802LYDWR Datasheet

MFR RecommendedRFQ

M48T35AV-10PC1

STMicroelectronicsIn Stock: 1390M48T35AV-10PC1 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the DS12885SN are identified based on the following critical parameters that determine functional compatibility:

Primary Substitution Criteria:

• Clock/Calendar functionality with parallel interface
• 114B memory capacity
• Time format support (HH:MM:SS with 12/24 hour modes)
• Date format support (YY-MM-DD-dd)
• Alarm, daylight savings, and leap year features
• NVSRAM capability
• Surface mount packaging

Substitution Categories:

Direct Equivalent (Same Package): DS12885SN+ maintains identical electrical specifications, package footprint (24-SOIC), and feature set while offering active product status and RoHS3 compliance.

Functional Equivalent (Different Package): BQ3285S-SB2 provides equivalent core RTC functionality in the same 24-SOIC package with active status and RoHS3 compliance, though operating temperature range is narrower (0°C ~ 70°C vs. -40°C ~ 85°C).

Alternative with Package Change: BQ4802LYDWR offers RTC functionality in a 28-SOIC package with supervisor and watchdog timer features, but operates at lower supply voltage (2.7V ~ 3.6V) and narrower temperature range.

Through-Hole Alternative: M48T35AV-10PC1 provides RTC functionality in a 28-DIP through-hole package for applications requiring different mounting technology, with 24-hour time format and narrower operating specifications.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Recommended Primary Choice): DS12885SN+ is the optimal substitute when package footprint and electrical specifications must remain unchanged. This part maintains identical 24-SOIC surface mount packaging and 4.5V ~ 5.5V supply voltage range. The transition from obsolete to active product status ensures long-term availability. RoHS3 compliance addresses modern regulatory requirements while maintaining full backward compatibility with existing PCB layouts and designs.

For Same-Package Functional Equivalent: BQ3285S-SB2 provides equivalent RTC functionality within the same 24-SOIC package footprint. This Texas Instruments device maintains parallel interface and core clock/calendar features. The narrower operating temperature range (0°C ~ 70°C) requires verification against application requirements if extended temperature operation below 0°C or above 70°C is necessary. Active product status and RoHS3 compliance support long-term supply chain stability.

For Enhanced Feature Set with Package Change: BQ4802LYDWR introduces supervisor and watchdog timer functionality in a 28-SOIC package. This substitution requires PCB redesign due to package change from 24-SOIC to 28-SOIC. The lower supply voltage requirement (2.7V ~ 3.6V) necessitates power supply circuit modifications. This option is suitable for new designs or major revisions where additional supervisory features provide system-level benefits.

For Through-Hole Mounting Applications: M48T35AV-10PC1 addresses applications requiring through-hole mounting technology in a 28-DIP package. This STMicroelectronics Timekeeper® series device requires significant PCB layout changes and is appropriate for legacy system updates or applications where surface mount technology is not feasible. The 24-hour time format (without 12-hour mode) and narrower operating specifications require design verification.

Frequently Asked Questions (FAQ)

Q: Can DS12885SN+ be used as a direct drop-in replacement for DS12885SN?

A: Yes. DS12885SN+ maintains identical electrical specifications, package footprint (24-SOIC), memory capacity (114B), and feature set. No PCB modifications are required. The primary differences are active product status and RoHS3 compliance, which represent improvements over the obsolete original part.

Q: What are the key differences between BQ3285S-SB2 and the original DS12885SN?

A: BQ3285S-SB2 provides equivalent RTC functionality and identical 24-SOIC packaging. The operating temperature range is narrower (0°C ~ 70°C vs. -40°C ~ 85°C). Applications requiring operation below 0°C or above 70°C must use DS12885SN+ or verify BQ3285S-SB2 suitability through Texas Instruments technical documentation.

Q: Why does BQ4802LYDWR have a different package (28-SOIC vs. 24-SOIC)?

A: BQ4802LYDWR includes additional supervisor and watchdog timer functionality, requiring additional pins and a larger 28-SOIC package. This substitution requires PCB redesign and is suitable for new designs or major revisions where these features provide system-level benefits.

Q: Is M48T35AV-10PC1 suitable for surface mount applications?

A: No. M48T35AV-10PC1 is a through-hole 28-DIP package device. This substitution is appropriate only for applications requiring through-hole mounting technology or legacy system updates. Surface mount applications should use DS12885SN+, BQ3285S-SB2, or BQ4802LYDWR.

Q: What supply voltage considerations apply when selecting a substitute?

A: DS12885SN and DS12885SN+ operate at 4.5V ~ 5.5V. BQ3285S-SB2 also operates at 4.5V ~ 5.5V. BQ4802LYDWR requires 2.7V ~ 3.6V, necessitating power supply circuit modifications. M48T35AV-10PC1 requires 3V ~ 3.6V. Verify power supply compatibility before substitution.

Q: Are all substitute parts RoHS3 compliant?

A: DS12885SN is RoHS non-compliant. All substitute parts (DS12885SN+, BQ3285S-SB2, BQ4802LYDWR, M48T35AV-10PC1) are RoHS3 compliant, supporting modern regulatory and procurement requirements.

Q: What is the primary reason to substitute the obsolete DS12885SN?

A: DS12885SN is classified as obsolete, creating long-term supply chain risk. Active substitute parts ensure continued availability for production, field repairs, and design updates. DS12885SN+ is the recommended choice for maintaining existing designs with minimal modification.