RTC-4574JE:B3 Equivalent & Substitute Parts

Part Overview

The RTC-4574JE:B3 is a Real Time Clock (RTC) IC manufactured by EPSON, designed for clock/calendar applications with 3-wire serial interface. This component provides timekeeping functionality with alarm and leap year support across a wide supply voltage range of 1.6V to 5.5V. The part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement continuity.

Key Parameters

Parameter	RTC-4574JE:B3
Manufacturer	EPSON
Category	Clock/Timing
Type	Clock/Calendar
Interface	3-Wire Serial
Time Format	HH:MM:SS (24 hr)
Date Format	YY-MM-DD-dd
Features	Alarm, Leap Year
Voltage - Supply	1.6V ~ 5.5V
Current - Timekeeping (Max)	1µA ~ 2µA @ 3V ~ 5V
Operating Temperature	-40°C ~ 85°C
Mounting Type	Surface Mount
Package / Case	20-LSSOJ (0.213", 5.40mm Width)
RoHS Status	ROHS3 Compliant
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the RTC-4574JE:B3 is determined by the following critical parameters:

Interface Compatibility: The main part uses 3-wire serial interface. Substitute parts must maintain this interface type to ensure firmware and PCB design compatibility without modification.

Functional Features: Alarm and leap year support are core requirements. Substitute parts must provide these features as minimum functionality.

Supply Voltage Range: The main part operates from 1.6V to 5.5V. Substitute parts must support overlapping or equivalent voltage ranges to function in the same application circuits.

Time and Date Format: Both 24-hour and YY-MM-DD-dd formats are required. Substitute parts must support these formats.

Operating Temperature Range: -40°C to 85°C defines the thermal operating envelope. Substitute parts must meet or exceed this range.

Mounting and Package: Surface mount technology with compatible package dimensions ensures PCB layout compatibility.

Compliance: RoHS3 compliance is mandatory for regulatory and procurement requirements.

Based on these criteria, the following parts qualify as substitutes:

S-35192A-I8T1U (ABLIC Inc.) – Maintains 3-wire serial interface, alarm and leap year features, compatible voltage range, and surface mount package.
DS1343D-33+ (Analog Devices Inc./Maxim Integrated) – Provides clock/calendar functionality with alarm and leap year; however, uses SPI interface instead of 3-wire serial, requiring design modification.

Parameter Comparison

Parameter	RTC-4574JE:B3	S-35192A-I8T1U	DS1343D-33+
Manufacturer	EPSON	ABLIC Inc.	Analog Devices Inc./Maxim Integrated
Category	Clock/Timing	Clock/Timing	Clock/Timing
Type	Clock/Calendar	Clock/Calendar	Clock/Calendar
Interface	3-Wire Serial	3-Wire Serial	SPI
Time Format	HH:MM:SS (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
Features	Alarm, Leap Year	Alarm, Leap Year	Alarm, Leap Year, NVRAM, Square Wave Output, Trickle Charger
Voltage - Supply	1.6V ~ 5.5V	1.3V ~ 5.5V	3V ~ 5.5V
Current - Timekeeping (Max)	1µA ~ 2µA @ 3V ~ 5V	8µA ~ 14µA @ 3V ~ 5V	120µA ~ 160µA @ 3.63V ~ 5.5V
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount
Package / Case	20-LSSOJ (0.213", 5.40mm Width)	8-SMD, Flat Lead	14-WFDFN Exposed Pad
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Obsolete	Active	Active

Engineering Selection Recommendations

S-35192A-I8T1U (Preferred Substitute): This part maintains direct interface compatibility with the RTC-4574JE:B3 through its 3-wire serial interface, eliminating the need for firmware or PCB redesign. It provides equivalent alarm and leap year functionality, operates across a compatible voltage range (1.3V ~ 5.5V), and meets the same operating temperature specification. The part is currently active in production with ROHS3 compliance. The 8-SMD package requires PCB layout modification due to different package geometry. Current timekeeping consumption is higher (8µA ~ 14µA) compared to the original part.

DS1343D-33+ (Alternative with Design Modification Required): This part offers extended functionality including NVRAM, square wave output, and trickle charger capabilities. However, it uses SPI interface instead of 3-wire serial, requiring firmware modification and potential PCB redesign. The part is active in production with ROHS3 compliance. Operating voltage range is narrower (3V ~ 5.5V), and current consumption during timekeeping is significantly higher (120µA ~ 160µA). The 14-WFDFN package differs from the original. This option is suitable only when design modifications are feasible and extended features are beneficial.

Frequently Asked Questions (FAQ)

Q: Can S-35192A-I8T1U be used as a direct drop-in replacement for RTC-4574JE:B3?

A: S-35192A-I8T1U maintains interface and functional compatibility but requires PCB layout modification due to different package geometry (8-SMD vs. 20-LSSOJ). Firmware compatibility is preserved through the 3-wire serial interface.

Q: Why does DS1343D-33+ require design modification?

A: DS1343D-33+ uses SPI interface instead of 3-wire serial. This requires firmware changes to the communication protocol and potential PCB routing modifications. The narrower supply voltage range (3V ~ 5.5V minimum vs. 1.6V) may also affect low-voltage applications.

Q: What is the impact of higher current consumption in substitute parts?

A: S-35192A-I8T1U draws 8µA ~ 14µA during timekeeping compared to 1µA ~ 2µA in the original part. DS1343D-33+ draws 120µA ~ 160µA. Higher consumption affects battery life in battery-backed applications and thermal design in power-constrained systems.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. Both S-35192A-I8T1U and DS1343D-33+ are ROHS3 compliant, meeting regulatory requirements equivalent to the original RTC-4574JE:B3.

Q: What are the package considerations for substitution?

A: The original RTC-4574JE:B3 uses 20-LSSOJ package. S-35192A-I8T1U uses 8-SMD flat lead package, and DS1343D-33+ uses 14-WFDFN exposed pad package. Each requires distinct PCB footprint design and layout considerations.

Q: Can both substitute parts support 24-hour time format?

A: Yes. Both S-35192A-I8T1U and DS1343D-33+ support 12/24-hour selectable time format, providing compatibility with the original 24-hour requirement.

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