DS1647-120 Equivalent & Substitute Parts

Part Overview

The DS1647-120 is a Real Time Clock (RTC) IC with integrated Clock/Calendar functionality, 512KB NVSRAM, and parallel interface in a 32-DIP through-hole package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing system support, maintenance, and new design implementations where legacy compatibility or similar functionality is required.

Key Parameters

Parameter	DS1647-120
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 @ 4.5V ~ 5.5V
Operating Temperature	0°C ~ 70°C
Mounting Type	Through Hole
Package / Case	32-DIP Module (0.600", 15.24mm)
Product Status	Obsolete
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitution for the DS1647-120 is determined by the following critical parameters:

Interface Type: Parallel interface requirement
Time/Date Format: HH:MM:SS (24 hr) and YY-MM-DD-dd format support
Operating Temperature Range: 0°C ~ 70°C
Voltage Supply Range: 4.5V ~ 5.5V compatibility
Mounting Type: Through-hole or surface-mount alternatives
Package Compatibility: DIP pin count and physical dimensions

Substitute parts are grouped into two categories:

Category 1 - Direct Functional Equivalents (32-DIP Through-Hole)

DS1747-70+: Active product status, same 32-DIP package, enhanced feature set (Y2K support)

Category 2 - Functional Alternatives (Different Package Formats)

M48T02-150PC1: 24-DIP through-hole, reduced pin count, lower current consumption
M48T12-150PC1: 24-DIP through-hole, reduced pin count, lower current consumption
M48T37Y-70MH1F: 44-BSOP surface-mount, enhanced features (Alarm, Watchdog Timer)
M48T58-70PC1: 28-DIP through-hole, intermediate pin count

Parameter Comparison

Parameter	DS1647-120	DS1747-70+	M48T02-150PC1	M48T12-150PC1	M48T37Y-70MH1F	M48T58-70PC1
Manufacturer	Analog Devices Inc./Maxim Integrated	Analog Devices Inc./Maxim Integrated	STMicroelectronics	STMicroelectronics	STMicroelectronics	STMicroelectronics
Type	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar
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 (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
Interface	Parallel	Parallel	Parallel	Parallel	Parallel	Parallel
Voltage Supply	4.5V ~ 5.5V	4.5V ~ 5.5V	4.75V ~ 5.5V	4.5V ~ 5.5V	4.5V ~ 5.5V	4.75V ~ 5.5V
Current - Timekeeping (Max)	4mA @ 4.5V ~ 5.5V	4mA @ 5V	3mA @ 4.7V ~ 5.5V	3mA @ 4.5V ~ 5.5V	3mA @ 4.5V ~ 5.5V	3mA @ 4.75V ~ 5.5V
Operating Temperature	0°C ~ 70°C	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	Through Hole
Package / Case	32-DIP Module (0.600", 15.24mm)	32-DIP Module (0.600", 15.24mm)	24-DIP Module (0.600", 15.24mm)	24-DIP Module (0.600", 15.24mm)	44-BSOP (0.337", 8.56mm Width)	28-DIP Module (0.600", 15.24mm)
Product Status	Obsolete	Active	Active	Active	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
REACH Status	REACH Affected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

For Direct Package Replacement (32-DIP Through-Hole)

DS1747-70+ is the primary substitute for DS1647-120. Both components share identical 32-DIP package geometry and through-hole mounting. DS1747-70+ is an active product with ROHS3 compliance and REACH unaffected status, addressing regulatory requirements that the obsolete DS1647-120 does not meet. The DS1747-70+ includes Y2K support as an additional feature.

For Reduced Pin Count Applications (24-DIP Through-Hole)

M48T02-150PC1 and M48T12-150PC1 provide functional clock/calendar capability in a 24-DIP package. Both are active products with ROHS3 compliance and REACH unaffected status. These alternatives reduce current consumption to 3mA and are suitable for designs where pin count reduction is acceptable. M48T12-150PC1 supports the full 4.5V ~ 5.5V supply range, matching the original specification more closely than M48T02-150PC1.

For Surface-Mount Integration (44-BSOP)

M48T37Y-70MH1F offers surface-mount integration in a 44-BSOP package with enhanced features including alarm and watchdog timer functionality. This option is suitable for new designs or board redesigns requiring surface-mount technology. ROHS3 compliance and REACH unaffected status are confirmed.

For Intermediate Pin Count (28-DIP Through-Hole)

M48T58-70PC1 provides a 28-DIP through-hole option with reduced current consumption (3mA) and ROHS3 compliance. This alternative bridges pin count between the 24-DIP and 32-DIP options.

All substitute parts maintain parallel interface, 24-hour time format, YY-MM-DD-dd date format, and 0°C ~ 70°C operating temperature range compatibility with the original DS1647-120 specification.

Frequently Asked Questions (FAQ)

Q: Can DS1747-70+ be used as a direct replacement for DS1647-120 in existing designs?

A: Yes. DS1747-70+ shares the identical 32-DIP package footprint and through-hole mounting with DS1647-120. Both support parallel interface, 4.5V ~ 5.5V supply voltage, HH:MM:SS (24 hr) time format, and YY-MM-DD-dd date format. Pin-for-pin compatibility is maintained. DS1747-70+ is an active product with current regulatory compliance.

Q: What are the differences between the 24-DIP alternatives (M48T02-150PC1, M48T12-150PC1) and the original 32-DIP package?

A: The 24-DIP alternatives reduce pin count from 32 to 24, requiring PCB layout modification. Both maintain parallel interface and clock/calendar functionality. Current consumption is reduced to 3mA compared to 4mA in the original. M48T12-150PC1 supports 4.5V ~ 5.5V supply range; M48T02-150PC1 requires 4.75V ~ 5.5V minimum. Physical package dimensions remain 0.600" (15.24mm) width for through-hole mounting.

Q: Is M48T37Y-70MH1F suitable for legacy through-hole designs?

A: No. M48T37Y-70MH1F is a surface-mount component in 44-BSOP package requiring SNAPHAT socket. This option is intended for new designs or board redesigns incorporating surface-mount technology. It is not compatible with through-hole PCB layouts designed for DIP packages.

Q: What compliance advantages do the substitute parts offer over DS1647-120?

A: All substitute parts are ROHS3 compliant and REACH unaffected, whereas DS1647-120 is RoHS non-compliant and REACH affected. For applications subject to environmental or regulatory requirements, the substitute parts provide current compliance status. DS1647-120 remains functional for legacy systems without regulatory constraints.

Q: Can I use M48T58-70PC1 as an alternative to the 24-DIP options?

A: Yes. M48T58-70PC1 is a 28-DIP through-hole option that maintains parallel interface, clock/calendar functionality, and 0°C ~ 70°C operating temperature. It requires 4.75V ~ 5.5V supply voltage and consumes 3mA during timekeeping. The 28-DIP package is intermediate between 24-DIP and 32-DIP options, requiring corresponding PCB layout adjustment.

Q: Are all substitute parts available in the same packaging format (Tube, Tape & Reel)?

A: No. DS1747-70+, M48T02-150PC1, M48T12-150PC1, and M48T58-70PC1 are supplied in Tube packaging. M48T37Y-70MH1F is supplied in Tape & Reel (TR) format for surface-mount applications. Packaging format selection depends on assembly process requirements and volume.

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