Equivalent & Substitute Parts for RTC-4543SA:B3

Part Overview

The RTC-4543SA: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 leap year support and operates across a wide supply voltage range of 2.5V to 5.5V. The product is currently classified as obsolete, making equivalent and substitute parts necessary for ongoing system maintenance, redesigns, and new production requirements.

Substiute Parts

RTC-4543SA:B3 ROHS

EPSONIn Stock: 997RTC-4543SA:B3 ROHS Datasheet

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DS1302+

Analog Devices Inc./Maxim IntegratedIn Stock: 27034DS1302+ Datasheet

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DS1302S+

Analog Devices Inc./Maxim IntegratedIn Stock: 1952DS1302S+ Datasheet

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DS1302Z+T&R

Analog Devices Inc./Maxim IntegratedIn Stock: 20522DS1302Z+T&R Datasheet

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DS1305+

Analog Devices Inc./Maxim IntegratedIn Stock: 3751DS1305+ Datasheet

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DS1305E+T&R

Analog Devices Inc./Maxim IntegratedIn Stock: 5129DS1305E+T&R Datasheet

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DS1306N+

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

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DS1344E-3+T&R

Analog Devices Inc./Maxim IntegratedIn Stock: 2469DS1344E-3+T&R Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution for the RTC-4543SA:B3 is determined by the following critical parameters:

Interface Compatibility: The main part uses 3-Wire Serial interface. Substitute parts must support this interface type to maintain firmware and hardware compatibility without redesign.

Voltage Supply Range: The RTC-4543SA:B3 operates at 2.5V ~ 5.5V. Substitute parts must support overlapping or equivalent voltage ranges to ensure operation in the same power supply environment.

Operating Temperature Range: The main part operates from -40°C to 85°C. Substitute parts with matching or wider temperature ranges ensure equivalent thermal performance.

Mounting Type: The main part is Surface Mount. Substitutes may include both Surface Mount and Through Hole variants, as these represent different assembly approaches rather than functional incompatibilities.

Time and Date Format: Both must support HH:MM:SS (24 hr) and YY-MM-DD-dd formats for direct functional replacement.

Leap Year Support: This feature must be present in substitute parts.

Substitute parts are grouped into two categories:

Group 1 - Direct 3-Wire Serial Substitutes: DS1302+ (8-DIP), DS1302S+ (8-SOIC), DS1302Z+T&R (8-SOIC). These parts maintain the 3-Wire Serial interface and are functionally compatible with the main part.

Group 2 - SPI Interface Alternatives: DS1305+, DS1305E+T&R, DS1306N+, DS1344E-3+T&R. These parts use SPI interface instead of 3-Wire Serial and require interface redesign but offer enhanced features such as alarm functionality and increased memory.

Parameter Comparison

Engineering Selection Recommendations

For Direct Interface Replacement (3-Wire Serial):

DS1302S+ and DS1302Z+T&R are the preferred substitutes when maintaining the 3-Wire Serial interface is required. Both are active products with ROHS3 compliance. DS1302S+ is available in 8-SOIC (0.209", 5.30mm Width) packaging, while DS1302Z+T&R is available in 8-SOIC (0.154", 3.90mm Width) packaging. Both support the required time and date formats with leap year functionality. Operating temperature range for DS1302 variants is 0°C to 70°C, which is narrower than the main part's -40°C to 85°C range. DS1302+ (8-DIP) is also available but requires through-hole assembly.

For Extended Temperature Range with Interface Redesign:

DS1306N+ and DS1344E-3+T&R both support the full -40°C to 85°C operating temperature range matching the main part. DS1306N+ uses SPI interface in 16-DIP through-hole packaging, while DS1344E-3+T&R uses SPI interface in 20-TSSOP surface-mount packaging. Both are active products with ROHS3 compliance. These options require interface redesign but provide additional features including alarm functionality and square wave output capability.

For Low Power Timekeeping:

DS1302 variants (DS1302+, DS1302S+, DS1302Z+T&R) offer superior timekeeping current consumption at 0.3µA to 1µA compared to the main part's 1µA to 3µA specification, making them suitable for battery-backed applications.

Compliance Considerations:

All substitute parts are ROHS3 compliant and carry REACH Unaffected status, matching the regulatory requirements of the main part.

Frequently Asked Questions (FAQ)

Q: Can DS1302 variants directly replace the RTC-4543SA:B3 without firmware changes?

A: DS1302 variants maintain the 3-Wire Serial interface and support identical time/date formats (HH:MM:SS 24-hour and YY-MM-DD-dd) with leap year functionality. However, package differences (8-SOIC or 8-DIP versus 14-SOIC) require PCB layout redesign. Firmware compatibility depends on the specific register map implementation in your application.

Q: What is the key difference between DS1302 and DS1305/DS1306 substitutes?

A: DS1302 variants use 3-Wire Serial interface, while DS1305 and DS1306 use SPI interface. This is a fundamental communication protocol difference requiring interface redesign. DS1305/DS1306 offer additional features including alarm functionality, increased memory (96B versus 31B), and square wave output capability.

Q: Why do DS1302 variants have a narrower operating temperature range than the main part?

A: DS1302 variants operate from 0°C to 70°C, while the RTC-4543SA:B3 operates from -40°C to 85°C. If your application requires the full -40°C to 85°C range, DS1306N+ or DS1344E-3+T&R are the appropriate substitutes, though they require SPI interface redesign.

Q: Are all substitute parts currently in active production?

A: Yes. All listed substitute parts have Active product status, ensuring ongoing availability and support. The main part RTC-4543SA:B3 is classified as Obsolete.

Q: What packaging options are available for surface-mount applications?

A: For surface-mount assembly, DS1302S+ (8-SOIC, 0.209" width), DS1302Z+T&R (8-SOIC, 0.154" width), DS1305E+T&R (20-TSSOP, 0.173" width), and DS1344E-3+T&R (20-TSSOP, 0.173" width) are available options.

Q: How does battery backup voltage support differ across substitutes?

A: The main part does not specify battery backup voltage. DS1302 variants support 2V to 5.5V battery backup. DS1305 variants support 2V to 5.5V battery backup. DS1344E-3+T&R supports an extended range of 1.3V to 5.5V battery backup, enabling operation with lower voltage battery sources.