Equivalent & Substitute Parts for 1337CSRI8

Part Overview

The 1337CSRI8 is a Real Time Clock (RTC) IC with Clock/Calendar functionality manufactured by Renesas Electronics Corporation. This device features I2C interface communication, alarm capability, leap year support, and square wave output in a 16-SOIC package. The product is currently obsolete, making equivalent substitute parts necessary for new designs, maintenance applications, and component sourcing.

Key Parameters

Parameter	1337CSRI8 Specification
Manufacturer	Renesas Electronics Corporation
Category	Clock/Timing
Type	Clock/Calendar
Interface	I2C
Package / Case	16-SOIC (0.295", 7.50mm Width)
Voltage - Supply	1.8V ~ 5.5V
Voltage - Supply, Battery	1.3V ~ 3.7V
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
Product Status	Obsolete
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the 1337CSRI8 is determined by the following critical parameters:

Primary Compatibility Criteria:

Interface: I2C, 2-Wire Serial communication protocol
Time Format: Support for 12/24-hour operation
Date Format: YY-MM-DD-dd calendar format
Operating Temperature Range: -40°C ~ 85°C
Mounting Type: Surface Mount
Voltage Supply Range: Minimum 1.8V operation capability

Secondary Compatibility Criteria:

Features: Alarm and Leap Year support (core functionality)
Square Wave Output capability
Moisture Sensitivity Level: MSL 1 (Unlimited)

Substitute parts are grouped into two categories based on package compatibility:

Category A - Direct Package Match (16-SOIC): DS1340C-33#T&R maintains the identical 16-SOIC package footprint, enabling direct PCB replacement without layout modifications.

Category B - Functional Equivalents (Alternative Packages): Remaining substitutes provide equivalent RTC functionality with I2C interface and required features but utilize different package formats (8-SOIC, 8-TSSOP, 10-SMD Module, 20-SOIC). These require PCB redesign or adapter solutions.

Parameter Comparison

Parameter	1337CSRI8	DS1340C-33#T&R	DS3232SN#T&R	M41T82RM6F	DS1338U-18+	DS1339U-3+T&R
Manufacturer	Renesas	Analog Devices/Maxim	Analog Devices/Maxim	STMicroelectronics	Analog Devices/Maxim	Analog Devices/Maxim
Package / Case	16-SOIC	16-SOIC	20-SOIC	8-SOIC	8-TSSOP	8-TSSOP
Interface	I2C	I2C, 2-Wire Serial	I2C, 2-Wire Serial	I2C, 2-Wire Serial	I2C, 2-Wire Serial	I2C, 2-Wire Serial
Voltage - Supply	1.8V ~ 5.5V	2.97V ~ 5.5V	2.3V ~ 5.5V	2.7V ~ 5.5V	1.71V ~ 5.5V	2.7V ~ 5.5V
Voltage - Supply, Battery	1.3V ~ 3.7V	1.3V ~ 5.5V	2.3V ~ 5.5V	2V ~ 5.5V	1.3V ~ 3.7V	1.3V ~ 3.7V
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Time Format	HH:MM:SS (12/24 hr)	HH:MM:SS (24 hr)	HH:MM:SS (12/24 hr)	HH:MM:SS:hh (24 hr)	HH:MM:SS (12/24 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
Alarm Feature	Yes	No	Yes	Yes	No	Yes
Leap Year Support	Yes	Yes	Yes	Yes	Yes	Yes
Square Wave Output	Yes	No	Yes	No	Yes	Yes
Product Status	Obsolete	Active	Active	Active	Active	Active
RoHS Status	Not Specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
MSL Rating	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

Direct Replacement (Identical Package): DS1340C-33#T&R is the primary substitute for applications requiring 16-SOIC package compatibility. This part maintains the same footprint as the 1337CSRI8, enabling direct PCB placement without layout modifications. The device is currently in active production status with ROHS3 compliance and REACH unaffected certification. Note that DS1340C-33#T&R does not include alarm or square wave output features; designs dependent on these functions require functional verification.

High-Capacity Alternative: DS3232SN#T&R provides expanded functionality with 236B memory, integrated SRAM, and TCXO/Crystal oscillator. This 20-SOIC package device supports both alarm and square wave output features matching the 1337CSRI8 specification. The larger package footprint requires PCB redesign. This part is actively produced with ROHS3 compliance.

Low-Power Compact Options: DS1338U-18+ and DS1339U-3+T&R offer 8-TSSOP packages with reduced footprint. DS1338U-18+ provides 56B NVSRAM memory without alarm capability. DS1339U-3+T&R includes alarm and trickle-charger features. Both support 12/24-hour time format and square wave output. These options require significant PCB layout changes.

STMicroelectronics Alternative: M41T82RM6F in 8-SOIC package provides alarm, leap year, SRAM, and watchdog timer functionality. This device operates at 2.7V minimum supply voltage and delivers 10µA timekeeping current at 5.5V. Package change from 16-SOIC to 8-SOIC necessitates PCB modification.

Module-Based Solutions: AB-RTCMC-32.768KHZ-B5GA-S3-T and AB-RTCMC-32.768KHZ-EOZ9-S3-DBT are 10-SMD module packages from Abracon LLC. These integrated modules include crystal oscillators and provide complete RTC functionality. The EOZ9 variant includes 8B EEPROM and trickle-charger. Module-based solutions require different PCB footprints and mounting considerations.

All recommended substitutes maintain -40°C ~ 85°C operating temperature range, MSL 1 rating, and I2C interface compatibility with the original 1337CSRI8 specification.

Frequently Asked Questions (FAQ)

Q: Can DS1340C-33#T&R replace 1337CSRI8 without PCB modification? A: Yes. DS1340C-33#T&R uses the identical 16-SOIC package, enabling direct footprint compatibility. However, verify that your design does not require alarm or square wave output functions, as DS1340C-33#T&R does not include these features.

Q: What is the primary difference between DS1338U-18+ and DS1339U-3+T&R? A: DS1338U-18+ lacks alarm functionality and operates with 56B NVSRAM memory. DS1339U-3+T&R includes alarm capability and trickle-charger feature. Both use 8-TSSOP packages and require PCB redesign from the original 16-SOIC layout.

Q: Are all substitute parts RoHS compliant? A: Yes. All recommended substitutes carry ROHS3 compliance certification. The original 1337CSRI8 RoHS status is not specified in available documentation.

Q: Which substitute provides the lowest timekeeping current consumption? A: M41T82RM6F delivers 10µA timekeeping current at 5.5V, the lowest among all listed substitutes. The original 1337CSRI8 specifies 0.6µA at 1.3V ~ 1.8V, which is lower but measured at reduced voltage levels.

Q: Can module-based solutions (Abracon parts) be used as direct replacements? A: No. Abracon 10-SMD module packages require different PCB footprints and mounting approaches compared to the 16-SOIC DIP package. These solutions are suitable for new designs where PCB layout can be modified to accommodate module integration.

Q: What voltage range is common across all substitutes? A: All substitutes support operation within the 2.3V ~ 5.5V range. The original 1337CSRI8 operates from 1.8V ~ 5.5V. Designs operating below 2.3V require DS1338U-18+ (1.71V minimum) or AB-RTCMC modules (1.2V minimum).

Q: Which substitute offers the most feature parity with 1337CSRI8? A: DS3232SN#T&R and DS1339U-3+T&R both include alarm, leap year, and square wave output features. DS3232SN#T&R additionally provides 236B SRAM and integrated TCXO/Crystal oscillator, offering expanded functionality beyond the original specification.

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