DS1747-70+ Real Time Clock IC Equivalent & Substitute Parts

Part Overview

The DS1747-70+ is an Active status Real Time Clock (RTC) IC manufactured by Analog Devices Inc./Maxim Integrated, designed for clock/calendar applications requiring parallel interface connectivity. This 32-DIP through-hole module integrates 512KB NVSRAM with leap year and Y2K compliance features, operating across 4.5V to 5.5V supply voltage range. Alternative equivalent parts become necessary when addressing specific application constraints including package form factor requirements, pin count compatibility, or supply voltage specifications that differ from the original design.

Key Parameters

Parameter	DS1747-70+
Manufacturer	Analog Devices Inc./Maxim Integrated
Category	Clock/Timing
Type	Clock/Calendar
Memory Size	512KB
Interface	Parallel
Time Format	HH:MM:SS (24 hr)
Date Format	YY-MM-DD-dd
Voltage - Supply	4.5V ~ 5.5V
Current - Timekeeping (Max)	4mA @ 5V
Operating Temperature	0°C ~ 70°C
Mounting Type	Through Hole
Package / Case	32-DIP Module (0.600", 15.24mm)
Product Status	Active
RoHS Status	ROHS3 Compliant
Features	Leap Year, NVSRAM, Y2K

Substitute Part Grouping Explanation

Substitution eligibility for the DS1747-70+ is determined by the following critical parameters:

Primary Compatibility Criteria:

Parallel interface architecture
24-hour time format capability
YY-MM-DD-dd date format support
Operating temperature range 0°C ~ 70°C
Supply voltage overlap within 4.5V ~ 5.5V range
Through-hole mounting configuration
Active product status
ROHS3 compliance

Package Considerations: Substitute parts may differ in pin count (24-DIP, 28-DIP, or 28-SOIC) and physical dimensions while maintaining functional equivalence through parallel interface architecture. Surface mount alternatives (28-SOIC) represent functional equivalents for applications permitting package transition.

Feature Alignment: All substitute candidates maintain leap year and calendar functionality. Additional features such as alarm, daylight savings, supervisor, or watchdog timer functions in substitute parts do not disqualify equivalence but represent extended capability sets.

Parameter Comparison

Parameter	DS1747-70+	M48T02-150PC1	M48T12-150PC1	M48T58-70PC1	BQ4802YDW
Manufacturer	Analog Devices Inc./Maxim Integrated	STMicroelectronics	STMicroelectronics	STMicroelectronics	Benchmarq
Type	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar
Interface	Parallel	Parallel	Parallel	Parallel	Parallel
Time Format	HH:MM:SS (24 hr)	HH:MM:SS (24 hr)	HH:MM:SS (24 hr)	HH:MM:SS (24 hr)	HH:MM:SS (12/24 hr)
Date Format	YY-MM-DD-dd	YY-MM-DD-dd	YY-MM-DD-dd	YY-MM-DD-dd	YY-MM-DD-dd
Voltage - Supply	4.5V ~ 5.5V	4.75V ~ 5.5V	4.5V ~ 5.5V	4.75V ~ 5.5V	4.5V ~ 5.5V
Current - Timekeeping (Max)	4mA @ 5V	3mA @ 4.7V ~ 5.5V	3mA @ 4.5V ~ 5.5V	3mA @ 4.75V ~ 5.5V	1.5mA (Typ) @ 4.5V ~ 5.5V
Operating Temperature	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Surface Mount
Package / Case	32-DIP Module (0.600", 15.24mm)	24-DIP Module (0.600", 15.24mm)	24-DIP Module (0.600", 15.24mm)	28-DIP Module (0.600", 15.24mm)	28-SOIC (0.295", 7.50mm Width)
Product Status	Active	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	Not Specified
Features	Leap Year, NVSRAM, Y2K	Leap Year	Leap Year	Leap Year	Alarm, Daylight Savings, Leap Year, Supervisor, Watchdog Timer

Engineering Selection Recommendations

Through-Hole DIP Package Equivalents (Direct PCB Compatibility):

M48T02-150PC1, M48T12-150PC1, and M48T58-70PC1 maintain through-hole mounting architecture compatible with existing PCB designs. These STMicroelectronics Timekeeper® series parts satisfy parallel interface, 24-hour time format, and calendar date format requirements. M48T12-150PC1 and M48T02-150PC1 operate within the full 4.5V ~ 5.5V supply range matching DS1747-70+ specifications. M48T58-70PC1 requires minimum 4.75V supply voltage, necessitating circuit verification for applications operating at 4.5V. All three maintain ROHS3 compliance and Active product status.

Surface Mount Alternative (Package Transition Required):

BQ4802YDW represents a functional equivalent for applications permitting surface mount technology transition. This Benchmarq part maintains parallel interface, 24-hour time format capability, and YY-MM-DD-dd date format. Operating temperature range and supply voltage specifications align with DS1747-70+ requirements. The 28-SOIC package requires PCB redesign and assembly process modification. RoHS compliance status is not specified for this part.

Supply Voltage Consideration:

Applications operating at 4.5V supply voltage should prioritize M48T12-150PC1 or BQ4802YDW, both rated for the full 4.5V ~ 5.5V range. M48T02-150PC1 and M48T58-70PC1 specify minimum 4.75V supply voltage and require circuit analysis to confirm compatibility with lower voltage operation.

Current Consumption:

M48T12-150PC1, M48T02-150PC1, and M48T58-70PC1 operate at 3mA timekeeping current, representing 25% reduction compared to DS1747-70+ 4mA specification. BQ4802YDW achieves 1.5mA typical timekeeping current, providing significant power efficiency advantage for battery-backed applications.

Frequently Asked Questions (FAQ)

Q: Can M48T02-150PC1 or M48T12-150PC1 directly replace DS1747-70+ in existing designs?

A: Both parts maintain parallel interface architecture, 24-hour time format, and YY-MM-DD-dd date format compatibility. However, pin count differs: DS1747-70+ uses 32-DIP while M48T02-150PC1 and M48T12-150PC1 use 24-DIP configuration. PCB redesign is required. M48T12-150PC1 operates across the full 4.5V ~ 5.5V supply range matching DS1747-70+ specifications.

Q: What is the difference between M48T02-150PC1 and M48T12-150PC1?

A: Both are STMicroelectronics Timekeeper® series 24-DIP through-hole parts with identical interface, time format, and date format specifications. M48T12-150PC1 operates across 4.5V ~ 5.5V supply voltage range. M48T02-150PC1 requires minimum 4.75V supply voltage. Selection depends on application supply voltage requirements.

Q: Is M48T58-70PC1 compatible with 4.5V supply voltage applications?

A: M48T58-70PC1 specifies minimum 4.75V supply voltage. Applications requiring 4.5V operation should select M48T12-150PC1 or BQ4802YDW instead.

Q: Can BQ4802YDW replace DS1747-70+ without PCB modification?

A: No. BQ4802YDW uses 28-SOIC surface mount package while DS1747-70+ uses 32-DIP through-hole configuration. PCB redesign and assembly process modification are required. BQ4802YDW maintains functional equivalence through parallel interface, 24-hour time format, and calendar date format support.

Q: Are all substitute parts ROHS3 compliant?

A: M48T02-150PC1, M48T12-150PC1, and M48T58-70PC1 are ROHS3 compliant. BQ4802YDW RoHS compliance status is not specified in available documentation.

Q: Which substitute part offers the lowest power consumption?

A: BQ4802YDW achieves 1.5mA typical timekeeping current, compared to 3mA for STMicroelectronics Timekeeper® series parts and 4mA for DS1747-70+. This represents 62.5% power reduction relative to the original part.

Q: Do substitute parts support leap year and Y2K functionality?

A: All substitute parts maintain leap year calendar functionality. DS1747-70+ explicitly specifies Y2K compliance. STMicroelectronics Timekeeper® series parts (M48T02-150PC1, M48T12-150PC1, M48T58-70PC1) and BQ4802YDW support leap year operation. Y2K compliance status for substitute parts is not explicitly documented.

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