DS1747-70 Real Time Clock IC Equivalent & Substitute Parts

Part Overview

The DS1747-70 is a Real Time Clock (RTC) IC with integrated Clock/Calendar functionality and 512KB NVSRAM, manufactured by Analog Devices Inc./Maxim Integrated. This 32-DIP through-hole component operates at 4.5V to 5.5V supply voltage and provides 24-hour time format with YY-MM-DD-dd date format. The DS1747-70 is classified as obsolete, making equivalent and substitute parts necessary for ongoing system support and new design implementations. Substitute parts must maintain functional compatibility across parallel interface architecture, voltage specifications, and timing accuracy requirements.

Substiute Parts

DS1747-70

Analog Devices Inc./Maxim IntegratedIn Stock: 2291DS1747-70 Datasheet

Current PartRFQ

DS1747-70+

Analog Devices Inc./Maxim IntegratedIn Stock: 1709DS1747-70+ Datasheet

DirectRFQ

BQ4802YDW

BenchmarqIn Stock: 1824BQ4802YDW Datasheet

MFR RecommendedRFQ

M48T02-150PC1

STMicroelectronicsIn Stock: 1525M48T02-150PC1 Datasheet

MFR RecommendedRFQ

M48T12-150PC1

STMicroelectronicsIn Stock: 2537M48T12-150PC1 Datasheet

MFR RecommendedRFQ

M48T58-70PC1

STMicroelectronicsIn Stock: 1546M48T58-70PC1 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the DS1747-70 are grouped based on the following critical parameters that determine functional compatibility:

Primary Substitution Criteria:

• Parallel interface architecture
• 24-hour time format (HH:MM:SS)
• YY-MM-DD-dd date format
• Operating voltage range 4.5V ~ 5.5V
• Operating temperature range 0°C ~ 70°C
• Through-hole mounting configuration
• Leap year functionality

Substitution Groups:

Group 1: Direct Pin-Compatible Substitutes (32-DIP Package)

• DS1747-70+ (Analog Devices Inc./Maxim Integrated): Active product status, identical 32-DIP package, ROHS3 compliant variant of the main part

Group 2: Functional Equivalents with Package Variation (24-DIP Package)

• M48T02-150PC1 (STMicroelectronics): 24-DIP package, parallel interface, 24-hour format, YY-MM-DD-dd date format, 4.75V ~ 5.5V supply, through-hole mounting
• M48T12-150PC1 (STMicroelectronics): 24-DIP package, parallel interface, 24-hour format, YY-MM-DD-dd date format, 4.5V ~ 5.5V supply, through-hole mounting

Group 3: Functional Equivalents with Package Variation (28-DIP Package)

• M48T58-70PC1 (STMicroelectronics): 28-DIP package, parallel interface, 24-hour format, YY-MM-DD-dd date format, 4.75V ~ 5.5V supply, through-hole mounting

Group 4: Alternative Architecture (Surface Mount)

• BQ4802YDW (Benchmarq): 28-SOIC surface mount package, parallel interface, 12/24-hour format, YY-MM-DD-dd date format, 4.5V ~ 5.5V supply, includes additional features (alarm, watchdog timer, supervisor)

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (No PCB Redesign): DS1747-70+ is the primary substitute. It maintains identical 32-DIP package configuration and pinout compatibility with the obsolete DS1747-70. The DS1747-70+ is active product status and ROHS3 compliant, addressing regulatory requirements while preserving existing board layouts.

For New Designs or PCB Redesign Scenarios: M48T12-150PC1 (STMicroelectronics) provides functional equivalence with active product status and ROHS3 compliance. The 24-DIP package requires PCB layout modification but maintains through-hole mounting and parallel interface architecture. Supply voltage range (4.5V ~ 5.5V) matches the original specification exactly.

For Surface Mount Integration: BQ4802YDW (Benchmarq) offers surface mount packaging in 28-SOIC format with active product status. This option requires PCB redesign but provides lower timekeeping current (1.5mA typical) and additional features including alarm, watchdog timer, and supervisor functions. The 12/24-hour time format option provides design flexibility.

For Extended Supply Voltage Margin: M48T58-70PC1 (STMicroelectronics) operates at 4.75V ~ 5.5V supply range. This part is suitable for applications with tighter power supply regulation and active product status with ROHS3 compliance.

Frequently Asked Questions (FAQ)

Q: Can DS1747-70+ be used as a direct replacement for DS1747-70? A: Yes. DS1747-70+ maintains identical 32-DIP package, pinout, and functional specifications. No PCB modifications are required. The primary difference is active product status and ROHS3 compliance versus the obsolete, non-compliant original.

Q: What are the key differences between 32-DIP and 24-DIP package substitutes? A: Package pin count differs (32 pins versus 24 pins), requiring PCB redesign. Functional parameters including parallel interface, 24-hour time format, and YY-MM-DD-dd date format remain equivalent. Verify pinout compatibility with specific datasheets before implementation.

Q: Is BQ4802YDW compatible with DS1747-70 applications? A: BQ4802YDW provides functional equivalence in parallel interface, time/date format, and operating voltage. However, the 28-SOIC surface mount package requires PCB redesign from through-hole configuration. Additional features (alarm, watchdog timer, supervisor) are present but not required for basic clock/calendar operation.

Q: What supply voltage considerations apply when selecting substitutes? A: DS1747-70 operates at 4.5V ~ 5.5V. M48T02-150PC1 and M48T58-70PC1 operate at 4.75V ~ 5.5V, requiring verification that system power supplies maintain minimum 4.75V. M48T12-150PC1 and BQ4802YDW match the original 4.5V ~ 5.5V range exactly.

Q: Are all substitute parts ROHS3 compliant? A: DS1747-70+ (Analog Devices), M48T02-150PC1, M48T12-150PC1, and M48T58-70PC1 (STMicroelectronics) are ROHS3 compliant. BQ4802YDW RoHS status is not specified in available documentation.

Q: What is the timekeeping current difference between substitutes? A: DS1747-70 and DS1747-70+ draw 4mA @ 5V. STMicroelectronics M48T series parts draw 3mA at their respective voltage ranges. BQ4802YDW draws 1.5mA typical @ 4.5V ~ 5.5V, offering reduced power consumption for battery-backed applications.

Q: Can substitutes be used interchangeably in existing designs? A: DS1747-70+ provides direct interchangeability without modification. M48T02-150PC1, M48T12-150PC1, and M48T58-70PC1 require PCB redesign due to different pin counts and package dimensions. BQ4802YDW requires PCB redesign for surface mount integration. Consult detailed datasheets for pinout verification before implementation.