RTC-4543SB:A Equivalent & Substitute Parts

Part Overview

The RTC-4543SB:A is a Real Time Clock (RTC) IC with Clock/Calendar functionality, manufactured by EPSON. This device operates as a 3-Wire Serial interface component in an 18-SOIC package and provides timekeeping with leap year support across a supply voltage range of 2.5V to 5.5V. The product is currently classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing system support and new design implementations.

Substiute Parts

RTC-4543SB:A

EPSONIn Stock: 1156RTC-4543SB:A Datasheet

Current PartRFQ

DS1306N+

Analog Devices Inc./Maxim IntegratedIn Stock: 1195DS1306N+ Datasheet

SimilarRFQ

DS1344D-3+T&R

Analog Devices Inc./Maxim IntegratedIn Stock: 4344DS1344D-3+T&R Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the RTC-4543SB:A is determined by the following critical parameters:

Core Functional Requirements:

• Clock/Calendar functionality with date and time tracking
• Leap year support
• Operating temperature range: -40°C to 85°C
• Supply voltage compatibility within or overlapping 2.5V ~ 5.5V range

Interface Compatibility: The RTC-4543SB:A uses a 3-Wire Serial interface. Substitute parts identified (DS1306N+ and DS1344D-3+T&R) employ SPI interface, which is a serial communication protocol capable of supporting equivalent timekeeping functionality. Both substitute parts maintain the same date/time format (YY-MM-DD-dd) and 24-hour time representation capability.

Electrical Parameters:

• Supply voltage ranges must overlap or exceed the original specification
• Operating temperature range must match or exceed -40°C to 85°C
• Timekeeping current consumption is secondary to functional compatibility

Packaging Considerations: The original part uses Surface Mount (18-SOIC). DS1306N+ is Through Hole (16-DIP), requiring PCB redesign. DS1344D-3+T&R is Surface Mount (14-WFDFN), maintaining mounting type compatibility.

Parameter Comparison

Engineering Selection Recommendations

DS1306N+ Selection Criteria:

• Active product status with ongoing manufacturer support
• ROHS3 compliant, meeting modern environmental standards
• Through-hole mounting requires PCB layout modification from the original surface-mount design
• Suitable for applications where PCB redesign is feasible and through-hole assembly is preferred
• Higher timekeeping current consumption (25.3µA ~ 81µA) compared to the original specification

DS1344D-3+T&R Selection Criteria:

• Active product status with ongoing manufacturer support
• ROHS3 compliant, meeting modern environmental standards
• Surface-mount package (14-WFDFN) maintains compatibility with original mounting type
• Smaller footprint than the original 18-SOIC package
• Preferred for designs requiring minimal PCB layout changes
• Supply voltage range (2.7V ~ 5.5V) is compatible with the original specification
• Extended battery supply voltage range (1.3V ~ 5.5V) provides additional operational flexibility

Both substitute parts provide active product status, ensuring long-term availability and technical support compared to the obsolete RTC-4543SB:A.

Frequently Asked Questions (FAQ)

Q: Can DS1306N+ and DS1344D-3+T&R directly replace the RTC-4543SB:A without firmware changes?

A: Both parts provide equivalent Clock/Calendar functionality with matching date/time formats (YY-MM-DD-dd) and leap year support. However, the interface change from 3-Wire Serial to SPI requires firmware modification to accommodate the different communication protocol. The substitute parts are functionally equivalent but not pin-compatible.

Q: What is the primary difference between DS1306N+ and DS1344D-3+T&R?

A: The DS1306N+ uses through-hole mounting (16-DIP package), while DS1344D-3+T&R uses surface-mount technology (14-WFDFN package). For designs currently using surface-mount assembly, DS1344D-3+T&R minimizes PCB redesign requirements. DS1306N+ is suitable for applications where through-hole assembly is preferred or required.

Q: Are the substitute parts RoHS compliant?

A: Yes. Both DS1306N+ and DS1344D-3+T&R are ROHS3 compliant, whereas the original RTC-4543SB:A is RoHS non-compliant. This compliance improvement is beneficial for applications subject to environmental regulations.

Q: How do the supply voltage ranges compare?

A: The RTC-4543SB:A operates at 2.5V ~ 5.5V. DS1306N+ operates at 2V ~ 5.5V (slightly lower minimum). DS1344D-3+T&R operates at 2.7V ~ 5.5V (slightly higher minimum). Both ranges are compatible with standard 3.3V and 5V logic systems. DS1344D-3+T&R additionally supports battery operation down to 1.3V.

Q: What additional features do the substitute parts provide?

A: Both DS1306N+ and DS1344D-3+T&R include Alarm functionality, NVRAM/NVSRAM, Square Wave Output, and Trickle Charger capabilities. The original RTC-4543SB:A provides only basic Clock/Calendar and Leap Year functions. These additional features enable expanded application flexibility without requiring additional external components.

Q: Is timekeeping current consumption a critical factor in selecting a substitute?

A: The RTC-4543SB:A specifies 1µA ~ 3µA timekeeping current, while DS1306N+ specifies 25.3µA ~ 81µA. For battery-backed applications with extended runtime requirements, this difference is significant. DS1344D-3+T&R does not specify timekeeping current in the provided data. Applications with strict power budget constraints should evaluate actual current consumption requirements against system specifications.