RTC-4574NB:B3 Equivalent & Substitute Parts

Part Overview

The RTC-4574NB: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 currently classified as obsolete, making equivalent and substitute parts necessary for ongoing system support and new design implementations.

Key Parameters

Parameter	Value
Manufacturer Part Number	RTC-4574NB: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	22-LFDFN
Product Status	Obsolete
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts for the RTC-4574NB:B3 are identified based on the following critical parameters that determine functional compatibility:

Core Functional Parameters:

Clock/Calendar functionality with timekeeping capability
Alarm and Leap Year support
Operating temperature range: -40°C ~ 85°C
RoHS3 compliance
Time and date format support (HH:MM:SS and YY-MM-DD-dd)

Interface Consideration: The RTC-4574NB:B3 uses a 3-Wire Serial interface. Substitute parts identified use SPI interface, which is a serial communication protocol compatible with 3-Wire Serial applications in many system implementations. Both protocols support serial data transmission suitable for RTC applications.

Voltage Supply Range: Substitute parts operate within overlapping supply voltage ranges that encompass the original part's 1.6V ~ 5.5V specification, ensuring compatibility in existing power supply designs.

Mounting and Package: The original part uses Surface Mount (22-LFDFN). Substitute parts include both Through Hole and Surface Mount options to accommodate different PCB design requirements.

Parameter Comparison

Parameter	RTC-4574NB:B3	DS1306N+	DS1344D-3+T&R
Manufacturer	EPSON	Analog Devices Inc./Maxim Integrated	Analog Devices Inc./Maxim Integrated
Type	Clock/Calendar	Clock/Calendar	Clock/Calendar
Interface	3-Wire Serial	SPI	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, NVSRAM, Square Wave Output, Trickle-Charger	Alarm, Leap Year, NVRAM, Square Wave Output, Trickle Charger
Memory Size	-	96B	96B
Voltage - Supply	1.6V ~ 5.5V	2V ~ 5.5V	2.7V ~ 5.5V
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Mounting Type	Surface Mount	Through Hole	Surface Mount
Package / Case	22-LFDFN	16-DIP (0.300", 7.62mm)	14-WFDFN Exposed Pad
Product Status	Obsolete	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

DS1306N+ Selection Criteria: The DS1306N+ is an active product from Analog Devices Inc./Maxim Integrated with ROHS3 compliance. This part is suitable for applications where Through Hole mounting is preferred or required. The 16-DIP package accommodates legacy PCB designs. Supply voltage range of 2V ~ 5.5V covers the upper portion of the original part's specification. This substitute includes additional features such as NVSRAM, Square Wave Output, and Trickle-Charger functionality.

DS1344D-3+T&R Selection Criteria: The DS1344D-3+T&R is an active product from Analog Devices Inc./Maxim Integrated with ROHS3 compliance, packaged in Tape & Reel format. This part maintains Surface Mount compatibility with the original RTC-4574NB:B3 in a 14-WFDFN package. Supply voltage range of 2.7V ~ 5.5V is compatible with systems operating above 2.7V. This substitute includes NVRAM, Square Wave Output, and Trickle Charger features.

Both substitute parts are active products with established supply chains, providing long-term availability compared to the obsolete RTC-4574NB:B3.

Frequently Asked Questions (FAQ)

Q: Can DS1306N+ and DS1344D-3+T&R directly replace RTC-4574NB:B3 without design modifications?

A: Both parts provide equivalent clock/calendar functionality with alarm and leap year support. However, interface differences (3-Wire Serial vs. SPI) and package differences require firmware and PCB layout modifications. The DS1344D-3+T&R maintains Surface Mount compatibility, while DS1306N+ requires Through Hole PCB design.

Q: What is the minimum supply voltage requirement when selecting a substitute?

A: The RTC-4574NB:B3 operates from 1.6V. DS1306N+ operates from 2V minimum, and DS1344D-3+T&R operates from 2.7V minimum. System designs operating below 2V cannot use these substitutes without additional voltage regulation.

Q: Are both substitute parts RoHS compliant?

A: Yes, both DS1306N+ and DS1344D-3+T&R are ROHS3 compliant, matching the compliance status of the original RTC-4574NB:B3.

Q: What are the key differences in timekeeping current consumption?

A: The RTC-4574NB:B3 draws 1µA ~ 2µA during timekeeping at 3V ~ 5V. The DS1306N+ draws 25.3µA ~ 81µA at 2V ~ 5V, representing higher power consumption. Current specifications for DS1344D-3+T&R are not provided in the available data.

Q: Which substitute part is recommended for new Surface Mount designs?

A: The DS1344D-3+T&R is the appropriate choice for new Surface Mount designs, maintaining the 22-LFDFN to 14-WFDFN form factor transition while preserving SMD mounting methodology.

Q: Can these parts operate with the same battery backup voltage as the original?

A: The RTC-4574NB:B3 does not specify battery backup voltage. DS1306N+ supports 2V ~ 5.5V battery backup. DS1344D-3+T&R supports 1.3V ~ 5.5V battery backup, providing broader battery compatibility options.

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