DS1337U+ Real Time Clock IC Equivalent & Substitute Parts

Part Overview

The DS1337U+ is an active-status Real Time Clock (RTC) IC manufactured by Analog Devices Inc./Maxim Integrated, designed for I2C/2-Wire Serial clock and calendar applications. This 8-TSSOP surface mount device provides timekeeping functionality with alarm capability, leap year support, and square wave output across a 1.8V to 5.5V supply range. The part is ROHS3 compliant with unlimited moisture sensitivity rating (MSL 1).

Equivalent and substitute parts are identified based on matching electrical specifications, interface protocols, package compatibility, and operational parameters that ensure functional interchangeability in clock/calendar timing applications.

Key Parameters

Parameter	DS1337U+ Specification
Manufacturer	Analog Devices Inc./Maxim Integrated
Category	Clock/Timing
Type	Clock/Calendar
Interface	I2C, 2-Wire Serial
Package / Case	8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
Voltage - Supply	1.8V ~ 5.5V
Current - Timekeeping (Max)	0.6µA @ 1.3V ~ 1.8V
Operating Temperature	-40°C ~ 85°C
Time Format	HH:MM:SS (12/24 hr)
Date Format	YY-MM-DD-dd
Features	Alarm, Leap Year, Square Wave Output
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant
MSL Rating	1 (Unlimited)
Product Status	Active

Substitute Part Grouping Explanation

Substitute parts for the DS1337U+ are classified based on the following critical parameters that determine functional interchangeability:

Primary Substitution Criteria:

Interface Protocol: I2C, 2-Wire Serial
Supply Voltage Range: 1.8V ~ 5.5V (minimum overlap requirement)
Operating Temperature: -40°C ~ 85°C
Time/Date Format: HH:MM:SS (12/24 hr) and YY-MM-DD-dd
Package Type: 8-TSSOP, 8-MSOP, or 8-SOIC surface mount packages
Core Features: Alarm and Leap Year support

Grouping Categories:

Group 1: Direct Package Match (8-TSSOP/8-MSOP) Parts maintaining identical or compatible 8-TSSOP/8-MSOP packaging with matching voltage and interface specifications.

Group 2: Alternative Package (8-SOIC) Parts with 8-SOIC packaging offering equivalent electrical functionality but different physical footprint, suitable for designs with 8-SOIC land patterns.

Group 3: Enhanced Feature Set Parts with additional memory, SRAM, or watchdog timer functionality while maintaining core I2C clock/calendar operation and compatible voltage ranges.

Parameter Comparison

Part Number	Manufacturer	Package	Voltage Supply	Timekeeping Current (Max)	Interface	Time Format	Features	RoHS Status	MSL
DS1337U+	Analog Devices/Maxim	8-TSSOP, 8-MSOP	1.8V ~ 5.5V	0.6µA @ 1.3V ~ 1.8V	I2C, 2-Wire	HH:MM:SS (12/24 hr)	Alarm, Leap Year, Square Wave	ROHS3	1
1337DVGI	Renesas Electronics	8-TSSOP	1.8V ~ 5.5V	0.6µA @ 1.3V ~ 1.8V	I2C, 2-Wire	HH:MM:SS (12/24 hr)	Alarm, Leap Year, Square Wave	ROHS3	3
1337DVGI8	Renesas Electronics	8-TSSOP	1.8V ~ 5.5V	0.6µA @ 1.3V ~ 1.8V	I2C, 2-Wire	HH:MM:SS (12/24 hr)	Alarm, Leap Year, Square Wave	ROHS3	3
1338-31DCGI	Renesas Electronics	8-SOIC	3.3V ~ 5.5V	5µA @ 3.63V ~ 5.5V	I2C, 2-Wire	HH:MM:SS (12/24 hr)	Leap Year, NVSRAM, Square Wave	ROHS3	1
ISL12020MIRZ-T7A	Renesas Electronics	20-PowerLFDFN	2.7V ~ 5.5V	14µA ~ 15µA @ 3V ~ 5V	I2C, 2-Wire	HH:MM:SS (12/24 hr)	Alarm, Daylight Savings, Leap Year, SRAM	ROHS3	1
ISL12058IBZ-T	Renesas Electronics	8-SOIC	1.8V ~ 3.6V	0.65µA @ 1.8V	I2C, 2-Wire	HH:MM:SS (12/24 hr)	Alarm, Leap Year	ROHS3	2
M41T80M6F	STMicroelectronics	8-SOIC	2V ~ 5.5V	2.4µA ~ 31µA @ 2V ~ 5.5V	I2C, 2-Wire	HH:MM:SS:hh (24 hr)	Alarm, Leap Year, Square Wave	ROHS3	1
M41T82ZM6F	STMicroelectronics	8-SOIC	2.38V ~ 5.5V	10µA @ 5.5V	I2C, 2-Wire	HH:MM:SS:hh (24 hr)	Alarm, Leap Year, SRAM, Watchdog Timer	ROHS3	1
MCP7940MT-I/MNY	Microchip Technology	8-WFDFN Exposed Pad	1.8V ~ 5.5V	1µA @ 5.5V	I2C, 2-Wire	HH:MM:SS (12/24 hr)	Alarm, Leap Year, Square Wave, SRAM	ROHS3	1
MCP79410-I/MS	Microchip Technology	8-TSSOP, 8-MSOP	1.8V ~ 5.5V	1.2µA @ 3.3V	I2C, 2-Wire	HH:MM:SS (12/24 hr)	Alarm, Leap Year, Square Wave, SRAM, Unique ID	ROHS3	1

Engineering Selection Recommendations

Direct Substitutes (Highest Compatibility):

The MCP79410-I/MS and Renesas 1337DVGI/1337DVGI8 parts provide the closest functional equivalence to DS1337U+. Both maintain 8-TSSOP/8-MSOP packaging, 1.8V ~ 5.5V supply voltage range, I2C interface, and core clock/calendar features. MCP79410-I/MS adds SRAM and Unique ID functionality while maintaining identical package and voltage specifications. All three parts are ROHS3 compliant and active-status products.

Alternative Package Options (8-SOIC):

For designs requiring 8-SOIC footprints, the ISL12058IBZ-T, M41T80M6F, and M41T82ZM6F provide I2C clock/calendar functionality. ISL12058IBZ-T operates at 1.8V ~ 3.6V with 0.65µA timekeeping current, suitable for low-voltage applications. M41T80M6F and M41T82ZM6F operate at 2V ~ 5.5V and 2.38V ~ 5.5V respectively, with M41T82ZM6F adding watchdog timer and SRAM features.

Enhanced Feature Alternatives:

The 1338-31DCGI (8-SOIC) and ISL12020MIRZ-T7A (20-PowerLFDFN) provide additional memory and functionality. The 1338-31DCGI includes 56B NVSRAM but operates at 3.3V ~ 5.5V minimum. ISL12020MIRZ-T7A offers 128B SRAM, daylight savings support, and alarm features in a 20-pin package, suitable for applications requiring expanded memory and advanced timing features.

Compliance Considerations:

All listed substitute parts maintain ROHS3 compliance and active product status. MSL ratings vary: DS1337U+, 1338-31DCGI, ISL12020MIRZ-T7A, M41T80M6F, M41T82ZM6F, MCP7940MT-I/MNY, and MCP79410-I/MS all carry MSL 1 (Unlimited). Renesas 1337DVGI and 1337DVGI8 carry MSL 3 (168 Hours), and ISL12058IBZ-T carries MSL 2 (1 Year). Selection should account for storage and handling requirements in manufacturing environments.

Frequently Asked Questions (FAQ)

Q: Can MCP79410-I/MS directly replace DS1337U+ in existing designs?

A: Yes. MCP79410-I/MS maintains identical 8-TSSOP/8-MSOP packaging, 1.8V ~ 5.5V supply voltage, I2C interface, and core clock/calendar features including alarm and leap year support. The part adds SRAM and Unique ID functionality without affecting pin compatibility or basic operation.

Q: What is the key difference between 8-TSSOP and 8-SOIC packages?

A: Package dimensions differ: 8-TSSOP measures 0.118" (3.00mm) width, while 8-SOIC measures 0.154" (3.90mm) width. These require different PCB land patterns and cannot be used interchangeably without redesign. Electrical functionality remains equivalent across compatible parts.

Q: Why do Renesas 1337DVGI and 1337DVGI8 have MSL 3 rating while DS1337U+ has MSL 1?

A: MSL (Moisture Sensitivity Level) ratings reflect component sensitivity to moisture absorption during storage. MSL 1 (Unlimited) allows indefinite storage without baking, while MSL 3 (168 Hours) requires baking after 168 hours of exposure to ambient humidity. This affects supply chain handling but does not impact electrical performance.

Q: Is ISL12058IBZ-T suitable for 5V applications?

A: No. ISL12058IBZ-T operates at 1.8V ~ 3.6V maximum supply voltage and is not suitable for 5V systems. For 5V applications, use DS1337U+, MCP79410-I/MS, MCP7940MT-I/MNY, M41T80M6F, or M41T82ZM6F.

Q: What additional features does MCP79410-I/MS provide compared to DS1337U+?

A: MCP79410-I/MS adds 64B SRAM memory and a Unique ID register. Both parts maintain identical core timekeeping, alarm, leap year, and square wave output functionality. The additional features do not affect pin compatibility or basic clock/calendar operation.

Q: Can ISL12020MIRZ-T7A replace DS1337U+ in space-constrained designs?

A: No. ISL12020MIRZ-T7A uses a 20-pin PowerLFDFN package versus DS1337U+'s 8-pin TSSOP, requiring significant PCB redesign. However, it provides enhanced functionality including daylight savings support, 128B SRAM, and alarm features for applications where additional features justify the larger footprint.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts carry ROHS3 compliance certification, matching DS1337U+ environmental standards.

Q: What is the timekeeping current difference between DS1337U+ and MCP79410-I/MS?

A: DS1337U+ draws 0.6µA at 1.3V ~ 1.8V, while MCP79410-I/MS draws 1.2µA at 3.3V. At equivalent voltage levels, MCP79410-I/MS typically draws slightly higher current due to additional SRAM functionality, but both remain in the low-power timekeeping range suitable for battery-backed applications.

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