DS14285Q Real Time Clock IC Equivalent & Substitute Parts

Part Overview

The DS14285Q is a Real Time Clock (RTC) IC with integrated Clock/Calendar functionality, manufactured by Analog Devices Inc./Maxim Integrated. This device provides parallel interface timekeeping with 114 bytes of NVSRAM, alarm capability, daylight savings support, and leap year compensation. The DS14285Q is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing system support.

Substiute Parts

DS14285Q

Analog Devices Inc./Maxim IntegratedIn Stock: 688DS14285Q Datasheet

Current PartRFQ

DS1685Q-5+

Analog Devices Inc./Maxim IntegratedIn Stock: 895DS1685Q-5+ Datasheet

MFR RecommendedRFQ

BQ3285S-SB2

Texas InstrumentsIn Stock: 1987BQ3285S-SB2 Datasheet

MFR RecommendedRFQ

M48T35AV-10PC1

STMicroelectronicsIn Stock: 1390M48T35AV-10PC1 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the DS14285Q is determined by the following critical parameters:

Functional Requirements:

• Parallel interface for clock/calendar operation
• Time format support: HH:MM:SS with 12/24 hour capability
• Date format support: YY-MM-DD-dd
• NVSRAM memory for data retention
• Alarm and square wave output functionality

Electrical Compatibility:

• Supply voltage range: 4.5V ~ 5.5V (primary operation)
• Battery backup voltage: 2.5V ~ 3.6V minimum
• Operating temperature: 0°C ~ 70°C

Physical Compatibility:

• Package type: 28-pin configuration
• Mounting type: Surface mount preferred for direct replacement

Three substitute parts meet these criteria with varying trade-offs in memory capacity, package form factor, and product status.

Parameter Comparison

Engineering Selection Recommendations

DS1685Q-5+ (Recommended Primary Substitute)

The DS1685Q-5+ is the manufacturer-recommended equivalent from Analog Devices Inc./Maxim Integrated. It maintains identical supply voltage specifications (4.5V ~ 5.5V), parallel interface, and 28-LCC package form factor. The DS1685Q-5+ offers expanded memory capacity (242B versus 114B) and is in active product status with ROHS3 compliance. This part provides direct functional compatibility with enhanced capabilities and modern environmental compliance.

BQ3285S-SB2 (Alternative from Texas Instruments)

The BQ3285S-SB2 from Texas Instruments provides functional equivalence with identical memory size (114B), feature set (alarm, daylight savings, leap year, NVSRAM, square wave output), and electrical specifications (4.5V ~ 5.5V supply). The primary trade-off is package form factor: 24-SOIC versus 28-LCC, requiring PCB layout modification. This part is in active status with ROHS3 compliance and offers an alternative supply source.

M48T35AV-10PC1 (Through-Hole Alternative)

The M48T35AV-10PC1 from STMicroelectronics (Timekeeper® series) provides clock/calendar functionality with parallel interface and identical operating temperature range. This part operates at 3V ~ 3.6V supply voltage, requiring voltage regulation modification from the original 4.5V ~ 5.5V specification. The 28-DIP through-hole package requires significant PCB redesign. This option is suitable only for applications where through-hole mounting is preferred and voltage supply modification is feasible. ROHS3 compliance is confirmed.

Frequently Asked Questions (FAQ)

Q: Can DS1685Q-5+ directly replace DS14285Q without PCB modification?

A: Yes. The DS1685Q-5+ maintains identical supply voltage (4.5V ~ 5.5V), battery backup voltage range (2.5V ~ 3.7V), parallel interface, and 28-LCC package footprint. Pin-to-pin compatibility is preserved. The expanded memory capacity (242B) is backward compatible with applications designed for 114B.

Q: What is the primary difference between DS14285Q and DS1685Q-5+?

A: The DS1685Q-5+ provides 242 bytes of NVSRAM compared to 114 bytes in the DS14285Q, includes Y2K support, and is in active product status with ROHS3 compliance. The DS14285Q is obsolete and RoHS non-compliant. Electrical and functional specifications remain compatible.

Q: Why does BQ3285S-SB2 require PCB modification?

A: The BQ3285S-SB2 uses a 24-SOIC package (0.295" width) instead of the 28-LCC package. Pin count and pinout differ, requiring PCB layout redesign. However, functional equivalence is maintained for clock/calendar, alarm, and NVSRAM operations.

Q: Is M48T35AV-10PC1 suitable for direct replacement?

A: No. The M48T35AV-10PC1 requires significant modifications: supply voltage must be reduced to 3V ~ 3.6V (versus 4.5V ~ 5.5V), and the through-hole 28-DIP package requires PCB redesign from surface mount. This option is only viable for new designs or major board revisions.

Q: What compliance certifications apply to substitute parts?

A: DS1685Q-5+, BQ3285S-SB2, and M48T35AV-10PC1 are all ROHS3 compliant and REACH unaffected. The original DS14285Q is RoHS non-compliant. All parts carry EAR99 export classification and HTSUS code 8542.39.0001.

Q: Are there differences in timekeeping current consumption?

A: Yes. The DS14285Q draws 0.5µA in timekeeping mode. The DS1685Q-5+ draws 3mA at 5V, and the M48T35AV-10PC1 draws 2mA at 3V ~ 3.6V. The BQ3285S-SB2 timekeeping current is not specified. For battery-backed applications, verify power budget requirements.

Q: Can 12-hour time format operation be maintained with all substitutes?

A: DS1685Q-5+ and BQ3285S-SB2 support both 12/24 hour formats. M48T35AV-10PC1 supports 24-hour format only. Applications requiring 12-hour operation must use DS1685Q-5+ or BQ3285S-SB2.