BQ4285S-SB2 Equivalent & Substitute Parts

Part Overview

The BQ4285S-SB2 is a Real Time Clock (RTC) IC with integrated Clock/Calendar functionality, manufactured by Texas Instruments. This device provides 114 bytes of NVSRAM, parallel interface connectivity, and essential timekeeping features including alarm, daylight savings, leap year support, and square wave output. The part is classified as obsolete, making equivalent and substitute parts necessary for ongoing system support and new design implementations.

Substiute Parts

BQ4285S-SB2

Texas InstrumentsIn Stock: 1360BQ4285S-SB2 Datasheet

Current PartRFQ

DS12885S+

Analog Devices Inc./Maxim IntegratedIn Stock: 2367DS12885S+ Datasheet

MFR RecommendedRFQ

DS12CR887-33+

Analog Devices Inc./Maxim IntegratedIn Stock: 3717DS12CR887-33+ Datasheet

MFR RecommendedRFQ

DS1554-70IND+

Analog Devices Inc./Maxim IntegratedIn Stock: 2099DS1554-70IND+ Datasheet

MFR RecommendedRFQ

DS1554P-70+

Analog Devices Inc./Maxim IntegratedIn Stock: 818DS1554P-70+ Datasheet

MFR RecommendedRFQ

DS1554WP-120+

Analog Devices Inc./Maxim IntegratedIn Stock: 1610DS1554WP-120+ Datasheet

MFR RecommendedRFQ

DS1557WP-120IND+

Analog Devices Inc./Maxim IntegratedIn Stock: 1614DS1557WP-120IND+ Datasheet

MFR RecommendedRFQ

DS1685QN-5+

Analog Devices Inc./Maxim IntegratedIn Stock: 780DS1685QN-5+ Datasheet

MFR RecommendedRFQ

DS1744-70IND+

Analog Devices Inc./Maxim IntegratedIn Stock: 1400DS1744-70IND+ Datasheet

MFR RecommendedRFQ

DS17487-5+

Analog Devices Inc./Maxim IntegratedIn Stock: 1528DS17487-5+ Datasheet

MFR RecommendedRFQ

M48T35AV-10PC1

STMicroelectronicsIn Stock: 1390M48T35AV-10PC1 Datasheet

MFR RecommendedRFQ

M48T35Y-70PC1

STMicroelectronicsIn Stock: 3110M48T35Y-70PC1 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the BQ4285S-SB2 is determined by the following critical parameters:

Primary Substitution Criteria:

• Package type and form factor (24-SOIC surface mount)
• Memory capacity (114B NVSRAM)
• Parallel interface architecture
• Supply voltage range (4.5V ~ 5.5V primary operation)
• Time and date format compatibility (HH:MM:SS 12/24 hr, YY-MM-DD-dd)
• Feature set (Alarm, Daylight Savings, Leap Year, Square Wave Output)
• Operating temperature range (0°C ~ 70°C minimum)
• RoHS3 compliance

Substitute Parts Identified:

Group 1: Direct Package Match (24-SOIC Surface Mount)

• DS12885S+ (Analog Devices Inc./Maxim Integrated) — Active status, identical package, matching voltage and feature set

Group 2: Functional Equivalents with Package Variations

• DS17487-5+ (24-DIP Through Hole) — Matching memory (4KB), features, and voltage; through-hole alternative
• DS12CR887-33+ (24-DIP Module) — Matching memory (114B), features; different voltage range (2.97V ~ 3.63V), through-hole package
• DS1554-70IND+ (32-DIP Module) — Larger memory (32KB), matching voltage, through-hole package
• DS1554P-70+ (34-PowerCap™ Module) — Larger memory (32KB), matching voltage, surface mount alternative
• DS1554WP-120+ (34-PowerCap™ Module) — Larger memory (32KB), lower voltage operation (2.97V ~ 3.63V), surface mount
• DS1557WP-120IND+ (34-PowerCap™ Module) — Largest memory (512KB), lower voltage operation (2.97V ~ 3.63V), extended temperature range
• DS1685QN-5+ (28-PLCC Surface Mount) — Larger memory (242B), matching voltage, different package form
• DS1744-70IND+ (28-DIP Module) — Larger memory (32KB), matching voltage, through-hole package

Parameter Comparison

Engineering Selection Recommendations

Primary Recommendation: DS12885S+

The DS12885S+ is the preferred direct substitute for the BQ4285S-SB2. This part maintains identical package geometry (24-SOIC), memory capacity (114B), supply voltage range (4.5V ~ 5.5V), battery voltage range (2.5V ~ 4V), time/date formats, and feature set. The DS12885S+ is manufactured by Analog Devices Inc./Maxim Integrated and holds active product status, ensuring long-term availability and supply chain stability. Both parts are ROHS3 compliant and carry equivalent regulatory certifications (REACH Unaffected, EAR99 classification).

Alternative Selections Based on Design Requirements:

For designs requiring through-hole mounting with matching feature set and voltage operation, the DS17487-5+ provides a direct functional equivalent in 24-DIP Module packaging. This part maintains the same supply voltage (4.5V ~ 5.5V), battery voltage (2.5V ~ 3.7V), time/date formats, and feature set, with active product status.

For applications requiring extended operating temperature range (-40°C ~ 85°C) with matching memory capacity (114B), the DS12CR887-33+ is suitable, though it operates at lower voltage (2.97V ~ 3.63V) and requires through-hole mounting.

For designs with increased memory requirements (32KB or greater), the DS1554-70IND+, DS1554P-70+, DS1554WP-120+, DS1557WP-120IND+, or DS1744-70IND+ provide scalable alternatives with active product status. Selection among these depends on specific mounting type (surface mount vs. through-hole), voltage requirements, and temperature range specifications.

All recommended substitutes maintain RoHS3 compliance and equivalent regulatory certifications to the original BQ4285S-SB2.

Frequently Asked Questions (FAQ)

Q: Can DS12885S+ be used as a direct replacement for BQ4285S-SB2 without PCB modifications?

A: Yes. The DS12885S+ is pin-compatible and functionally equivalent. Both parts use 24-SOIC surface mount packaging with identical pinout, voltage requirements (4.5V ~ 5.5V primary, 2.5V ~ 4V battery), and feature set. No PCB layout changes are required.

Q: What is the primary difference between DS12885S+ and DS17487-5+?

A: The DS12885S+ uses 24-SOIC surface mount packaging, while DS17487-5+ uses 24-DIP Module through-hole packaging. Both maintain identical electrical specifications and feature sets. Selection depends on board assembly method and available footprint space.

Q: Why do some substitute parts operate at 2.97V ~ 3.63V instead of 4.5V ~ 5.5V?

A: Parts such as DS12CR887-33+, DS1554WP-120+, and DS1557WP-120IND+ are designed for lower-voltage applications, typically 3.3V systems. These parts are not suitable for 5V-only designs without voltage regulation. Verify system voltage requirements before selection.

Q: Can I use DS1554-70IND+ or DS1744-70IND+ as replacements for BQ4285S-SB2?

A: These parts are functionally compatible but offer increased memory capacity (32KB vs. 114B). They require through-hole mounting and operate at 4.5V ~ 5.5V. Use these only if your design can accommodate the larger DIP package and if additional memory is beneficial or neutral to system operation.

Q: What is the significance of the PowerCap™ Module designation in DS1554P-70+ and DS1554WP-120+?

A: PowerCap™ Module refers to a specialized surface mount package with integrated capacitive energy storage. These parts maintain supply voltage during brief power interruptions. Select these if your design requires enhanced power-loss protection during timekeeping operations.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All substitute parts listed maintain ROHS3 compliance and REACH Unaffected status, matching the regulatory certifications of the original BQ4285S-SB2.

Q: Which substitute part offers the widest operating temperature range?

A: DS1557WP-120IND+ operates across -40°C ~ 85°C, the widest range among all substitutes. This part is suitable for industrial and extended-temperature applications. However, it requires 2.97V ~ 3.63V supply voltage and 34-PowerCap™ Module surface mount packaging.

Q: Can I substitute M48T35AV-10PC1 for BQ4285S-SB2?

A: M48T35AV-10PC1 is a functional alternative but operates at 3V ~ 3.6V (not 4.5V ~ 5.5V) and uses 28-DIP through-hole packaging. Use this part only if your design operates at 3.3V and can accommodate the larger DIP footprint. Memory capacity is not specified in available data.