DS1286I Equivalent & Substitute Parts

Part Overview

The DS1286I is a Real Time Clock (RTC) IC with Clock/Calendar functionality manufactured by Analog Devices Inc./Maxim Integrated. This through-hole 28-DIP module provides 50 bytes of SRAM, alarm capability, leap year support, square wave output, and watchdog timer functionality. The device operates at 4.5V to 5.5V with battery backup support from 2.4V to 4.6V, and supports both 12/24-hour time formats with YY-MM-DD-dd date format.

The DS1286I is classified as obsolete. Locating equivalent and substitute parts is necessary to support legacy system maintenance, board redesigns, and production continuity where original components are no longer available from primary sources.

Substiute Parts

DS1286I

Analog Devices Inc./Maxim IntegratedIn Stock: 1240DS1286I Datasheet

Current PartRFQ

BQ4802LYDWR

Texas InstrumentsIn Stock: 3828BQ4802LYDWR Datasheet

MFR RecommendedRFQ

BQ4802LYPWR

Texas InstrumentsIn Stock: 28912BQ4802LYPWR Datasheet

MFR RecommendedRFQ

M48T12-150PC1

STMicroelectronicsIn Stock: 2537M48T12-150PC1 Datasheet

MFR RecommendedRFQ

M48T35-70PC1

STMicroelectronicsIn Stock: 7799M48T35-70PC1 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the DS1286I is determined by the following critical parameters:

Primary Substitution Criteria:

• Parallel interface for direct pin compatibility
• Clock/Calendar functionality with time and date format support
• Alarm and watchdog timer features
• Operating voltage range compatibility (primary supply and battery backup)
• Package form factor (through-hole or surface mount with equivalent pin count)

Substitution Logic:

The DS1286I can be substituted by parts meeting these conditions:

1. M48T12-150PC1 and M48T35-70PC1 (STMicroelectronics Timekeeper® series): These through-hole 24-DIP and 28-DIP devices maintain parallel interface architecture and support leap year functionality. Both operate within compatible voltage ranges (4.5V ~ 5.5V for M48T12; 4.75V ~ 5.5V for M48T35) and support 24-hour time format with YY-MM-DD-dd date format. M48T35-70PC1 matches the 28-DIP package footprint of the DS1286I.

2. BQ4802LYDWR and BQ4802LYPWR (Texas Instruments): These surface-mount alternatives (28-SOIC and 28-TSSOP respectively) provide parallel interface RTC Clock/Calendar functionality with alarm, leap year, supervisor, and watchdog timer features. Operating voltage range is 2.7V ~ 3.6V with battery backup 2.4V ~ 4V. These require PCB redesign for surface-mount implementation but offer active product status and RoHS3 compliance.

Key Compatibility Constraints:

• M48T12-150PC1 uses 24-DIP package (fewer pins than DS1286I 28-DIP)
• BQ4802 variants require surface-mount PCB layout changes
• Operating temperature ranges vary: DS1286I supports -40°C ~ 85°C; substitutes support 0°C ~ 70°C
• Supply voltage ranges differ between through-hole and surface-mount alternatives

Parameter Comparison

Engineering Selection Recommendations

For Through-Hole PCB Designs (No Layout Redesign):

M48T35-70PC1 is the primary substitute for direct replacement. This STMicroelectronics Timekeeper® device maintains the 28-DIP through-hole package footprint, parallel interface, and supports leap year functionality with YY-MM-DD-dd date format. The device is in active production status with ROHS3 compliance. Operating voltage range (4.75V ~ 5.5V) is compatible with the DS1286I primary supply specification. Current consumption is lower (2mA @ 4.75V ~ 5.5V versus 7mA @ 5V), reducing power requirements. Operating temperature range is narrower (0°C ~ 70°C versus -40°C ~ 85°C), which may require thermal environment verification for extended temperature applications.

M48T12-150PC1 is an alternative through-hole option using 24-DIP package. This device requires PCB pin mapping verification due to reduced pin count compared to the DS1286I 28-DIP configuration. Voltage and current specifications are compatible with 5V supply designs.

For Surface-Mount PCB Designs (Layout Redesign Required):

BQ4802LYPWR (28-TSSOP) and BQ4802LYDWR (28-SOIC) are active Texas Instruments alternatives offering enhanced feature sets including daylight savings and supervisor functions. Both devices provide lower operating voltage (2.7V ~ 3.6V) and significantly reduced timekeeping current (1.5mA typical). ROHS3 compliance and active product status support long-term supply continuity. Surface-mount implementation requires PCB redesign and assembly process changes. Operating temperature range (0°C ~ 70°C) matches the STMicroelectronics alternatives.

Compliance Considerations:

All substitute parts listed are ROHS3 compliant and REACH unaffected, supporting modern manufacturing and environmental standards. The DS1286I is RoHS non-compliant; substitution enables compliance with current regulatory requirements.

Frequently Asked Questions (FAQ)

Q: Can M48T12-150PC1 be used as a direct pin-for-pin replacement for DS1286I?

A: No. M48T12-150PC1 uses 24-DIP package with fewer pins than the DS1286I 28-DIP configuration. Pin mapping must be verified against schematic requirements. M48T35-70PC1 is preferred for 28-DIP footprint compatibility.

Q: What are the key differences between M48T35-70PC1 and BQ4802 variants?

A: M48T35-70PC1 is through-hole 28-DIP, requiring no PCB layout changes. BQ4802 variants are surface-mount (SOIC or TSSOP), requiring PCB redesign. M48T35-70PC1 operates at 4.75V ~ 5.5V; BQ4802 variants operate at 2.7V ~ 3.6V. All three support parallel interface and leap year functionality.

Q: Does the DS1286I operating temperature range of -40°C ~ 85°C affect substitute selection?

A: Yes. All listed substitutes support 0°C ~ 70°C operating temperature. Applications requiring -40°C ~ 85°C operation must verify that substitute parts meet thermal environment specifications. Extended temperature variants may be available from manufacturers upon inquiry.

Q: Are the BQ4802LYDWR and BQ4802LYPWR functionally equivalent?

A: Yes. Both are Texas Instruments BQ4802 variants with identical electrical specifications. The difference is package form: BQ4802LYDWR is 28-SOIC (0.295" width); BQ4802LYPWR is 28-TSSOP (0.173" width). Selection depends on PCB layout space constraints and assembly capabilities.

Q: What is the impact of lower timekeeping current in substitute parts?

A: Substitute parts consume less power during timekeeping operation. M48T35-70PC1 draws 2mA (versus 7mA for DS1286I); BQ4802 variants draw 1.5mA typical. This reduces battery drain and heat generation, improving system efficiency and battery life.

Q: Can DS1286I be substituted in applications requiring square wave output?

A: The DS1286I provides square wave output functionality. M48T35-70PC1 and M48T12-150PC1 specifications do not list square wave output. BQ4802 variants do not list this feature. Applications dependent on square wave output require functional verification with substitute parts or alternative component selection.

Q: What compliance advantages do substitute parts offer?

A: All substitute parts are ROHS3 compliant and REACH unaffected, supporting current manufacturing regulations. The DS1286I is RoHS non-compliant. Substitution enables compliance with modern environmental and regulatory standards for new production and redesigned systems.