DS1746-70IND Real Time Clock IC Equivalent & Substitute Parts

Part Overview

The DS1746-70IND is a Real Time Clock (RTC) IC with integrated Clock/Calendar functionality, 128KB NVSRAM, and parallel interface designed for embedded systems requiring accurate timekeeping and date tracking. This part is classified as Obsolete, making equivalent and substitute parts necessary for new designs, production continuity, and system upgrades. The DS1746-70IND operates across industrial temperature ranges (-40°C to 85°C) with 4.5V to 5.5V supply voltage and supports 24-hour time format with leap year compensation and Y2K compliance.

Key Parameters

Parameter	Value
Manufacturer Part Number	DS1746-70IND
Manufacturer	Analog Devices Inc./Maxim Integrated
Category	Clock/Timing
Type	Clock/Calendar
Memory Size	128KB
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	-40°C ~ 85°C
Mounting Type	Through Hole
Package / Case	32-DIP Module (0.600", 15.24mm)
Product Status	Obsolete
Features	Leap Year, NVSRAM, Y2K

Substitute Part Grouping Explanation

Substitution for the DS1746-70IND is determined by the following critical parameters:

Primary Substitution Criteria:

Parallel interface requirement
24-hour time format and YY-MM-DD-dd date format support
4.5V to 5.5V supply voltage compatibility
Clock/Calendar functionality with leap year support
Through-hole or surface-mount package options

Substitution Categories:

Category 1: Direct Manufacturer Equivalent (Same Manufacturer, Active Status) DS1746-70IND+ is the direct successor from Analog Devices Inc./Maxim Integrated. It maintains identical electrical specifications, memory size (128KB), interface type (Parallel), and package configuration (32-DIP Module). The primary difference is product status (Active vs. Obsolete) and RoHS compliance upgrade (ROHS3 Compliant vs. RoHS non-compliant).

Category 2: STMicroelectronics Timekeeper® Series (Parallel Interface, Active Status) M48T02-150PC1, M48T35AV-10MH1F, and M48T37Y-70MH1F are STMicroelectronics alternatives within the Timekeeper® product line. These parts maintain parallel interface architecture and 24-hour time format with YY-MM-DD-dd date format. Substitution feasibility depends on package compatibility and operating temperature range alignment.

Category 3: Benchmarq Alternative (Different Package, Reduced Temperature Range) BQ4802YDW provides parallel interface RTC functionality with enhanced features (Alarm, Daylight Savings, Supervisor, Watchdog Timer) but operates within 0°C to 70°C temperature range, making it unsuitable for applications requiring -40°C to 85°C industrial operation.

Parameter Comparison

Parameter	DS1746-70IND	DS1746-70IND+	M48T02-150PC1	M48T35AV-10MH1F	M48T37Y-70MH1F	BQ4802YDW
Manufacturer	Analog Devices/Maxim	Analog Devices/Maxim	STMicroelectronics	STMicroelectronics	STMicroelectronics	Benchmarq
Product Status	Obsolete	Active	Active	Active	Active	Active
Type	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar
Interface	Parallel	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 (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	YY-MM-DD-dd
Voltage - Supply	4.5V ~ 5.5V	4.5V ~ 5.5V	4.75V ~ 5.5V	3V ~ 3.6V	4.5V ~ 5.5V	4.5V ~ 5.5V
Current - Timekeeping (Max)	4mA @ 5V	4mA @ 5V	3mA @ 4.7V ~ 5.5V	2mA @ 3V ~ 3.6V	3mA @ 4.5V ~ 5.5V	1.5mA (Typ) @ 4.5V ~ 5.5V
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°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	Surface Mount	Surface Mount	Surface Mount
Package / Case	32-DIP Module (0.600", 15.24mm)	32-DIP Module (0.600", 15.24mm)	24-DIP Module (0.600", 15.24mm)	28-SOP (0.350", 8.89mm Width)	44-BSOP (0.337", 8.56mm Width)	28-SOIC (0.295", 7.50mm Width)
Features	Leap Year, NVSRAM, Y2K	Leap Year, NVSRAM, Y2K	Leap Year	Leap Year	Alarm, Leap Year, Watchdog Timer	Alarm, Daylight Savings, Leap Year, Supervisor, Watchdog Timer
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	Not specified

Engineering Selection Recommendations

Recommended Primary Substitute: DS1746-70IND+

DS1746-70IND+ is the optimal substitute for direct replacement applications. It maintains identical electrical specifications, memory capacity (128KB), parallel interface architecture, and package configuration (32-DIP Module). The part is manufactured by the same company (Analog Devices Inc./Maxim Integrated) and carries Active product status with ROHS3 compliance, ensuring long-term availability and regulatory alignment.

Secondary Substitutes for Design Flexibility:

M48T02-150PC1 (STMicroelectronics) is suitable for applications where through-hole mounting and parallel interface are required, provided operating temperature does not exceed 70°C. This part offers reduced timekeeping current (3mA vs. 4mA) and is available in higher quantities.

M48T37Y-70MH1F (STMicroelectronics) accommodates surface-mount design requirements with parallel interface and 4.5V to 5.5V supply compatibility. Operating temperature limitation (0°C to 70°C) restricts use in industrial temperature range applications.

Not Recommended:

M48T35AV-10MH1F operates at 3V to 3.6V supply voltage, incompatible with 4.5V to 5.5V systems designed for DS1746-70IND.

BQ4802YDW is unsuitable for applications requiring -40°C to 85°C industrial temperature operation, as it operates only within 0°C to 70°C range.

Frequently Asked Questions (FAQ)

Q: Can DS1746-70IND+ be used as a direct replacement without PCB modifications?

A: Yes. DS1746-70IND+ maintains identical package configuration (32-DIP Module, 0.600" spacing), pin count, electrical specifications, and interface protocol. No PCB layout changes are required.

Q: What is the primary difference between DS1746-70IND and DS1746-70IND+?

A: Product status and regulatory compliance. DS1746-70IND is Obsolete with RoHS non-compliant status. DS1746-70IND+ is Active with ROHS3 compliance, ensuring continued manufacturing and regulatory alignment for new designs.

Q: Why is M48T35AV-10MH1F not recommended as a substitute?

A: M48T35AV-10MH1F operates at 3V to 3.6V supply voltage, while DS1746-70IND requires 4.5V to 5.5V. Direct substitution would cause circuit malfunction or component damage.

Q: Can M48T02-150PC1 replace DS1746-70IND in industrial temperature applications?

A: No. M48T02-150PC1 operates within 0°C to 70°C range, while DS1746-70IND supports -40°C to 85°C. Applications requiring full industrial temperature range must use DS1746-70IND+ or equivalent parts with matching temperature specifications.

Q: What are the package compatibility considerations for surface-mount alternatives?

A: M48T35AV-10MH1F and M48T37Y-70MH1F are surface-mount devices requiring PCB redesign, different soldering processes, and socket/connector modifications compared to through-hole DS1746-70IND. These changes necessitate full design validation and testing.

Q: Does BQ4802YDW offer functional advantages over DS1746-70IND?

A: BQ4802YDW includes additional features (Alarm, Daylight Savings, Supervisor, Watchdog Timer) not present in DS1746-70IND. However, its 0°C to 70°C operating temperature range and different package (28-SOIC) restrict its use to applications outside industrial temperature requirements.

Q: Are all substitute parts ROHS3 compliant?

A: DS1746-70IND+ (Active), M48T02-150PC1, M48T35AV-10MH1F, and M48T37Y-70MH1F are ROHS3 compliant. BQ4802YDW RoHS status is not specified in available documentation.

Q: What inventory considerations apply to these substitutes?

A: DS1746-70IND+ (830 Pcs), M48T02-150PC1 (1432 Pcs), M48T35AV-10MH1F (5782 Pcs), and M48T37Y-70MH1F (2200 Pcs) are available in stock. DS1746-70IND (703 Pcs) remains available but is Obsolete status.

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