RTC-4543SA:B3:PURE SN Equivalent & Substitute Parts

Part Overview

The RTC-4543SA:B3:PURE SN 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 part is currently obsolete, making equivalent and substitute components necessary for new designs, maintenance, and production continuity.

Substiute Parts

RTC-4543SA:B3:PURE SN

EPSONIn Stock: 700RTC-4543SA:B3:PURE SN Datasheet

Current PartRFQ

DS1302SN+T&R

Analog Devices Inc./Maxim IntegratedIn Stock: 30252DS1302SN+T&R Datasheet

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DS1302ZN+

Analog Devices Inc./Maxim IntegratedIn Stock: 1303DS1302ZN+ Datasheet

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DS1343E-33+

Analog Devices Inc./Maxim IntegratedIn Stock: 1298DS1343E-33+ Datasheet

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DS1343E-33+T&R

Analog Devices Inc./Maxim IntegratedIn Stock: 1042DS1343E-33+T&R Datasheet

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DS1344D-18+T&R

Analog Devices Inc./Maxim IntegratedIn Stock: 1345DS1344D-18+T&R Datasheet

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DS1344E-3+

Analog Devices Inc./Maxim IntegratedIn Stock: 1974DS1344E-3+ Datasheet

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S-35192A-I8T1U

ABLIC Inc.In Stock: 776S-35192A-I8T1U Datasheet

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Key Parameters

Substitute Part Grouping Explanation

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

Primary Compatibility Criteria:

• Interface type: 3-Wire Serial (required for direct functional replacement)
• Time format: HH:MM:SS with 24-hour capability
• Date format: YY-MM-DD-dd
• Operating temperature range: -40°C ~ 85°C
• Supply voltage overlap: Minimum 2.5V compatibility
• Leap year support
• Surface mount technology

Substitution Groups:

Group 1: Direct 3-Wire Serial Interface Substitutes Parts DS1302SN+T&R and DS1302ZN+ maintain the 3-wire serial interface with compatible time/date formats and operating temperature ranges. These parts support both 12/24-hour time formats and provide additional features including NVSRAM and trickle-charger functionality.

Group 2: SPI Interface Substitutes (Design Modification Required) Parts DS1343E-33+, DS1343E-33+T&R, DS1344D-18+T&R, and DS1344E-3+ use SPI interface instead of 3-wire serial. These require circuit redesign and firmware modification but offer expanded memory (96B) and additional features such as alarm and square wave output.

Group 3: Alternative 3-Wire Serial Substitute (Different Manufacturer) Part S-35192A-I8T1U from ABLIC Inc. provides 3-wire serial interface compatibility with alarm functionality and extended supply voltage range (1.3V ~ 5.5V).

Parameter Comparison

Engineering Selection Recommendations

For Direct Pin-Compatible Replacement (3-Wire Serial Interface):

DS1302SN+T&R and DS1302ZN+ are the primary substitutes for the RTC-4543SA:B3:PURE SN. Both parts maintain 3-wire serial interface compatibility, support the required time and date formats, and operate within the -40°C to 85°C temperature range. DS1302SN+T&R offers cut tape and digi-reel packaging with 30,200 units in stock, while DS1302ZN+ is available in tube packaging with 1,217 units in stock. Both are active products with ROHS3 compliance and demonstrate lower timekeeping current consumption (0.3µA ~ 1µA) compared to the original part. The DS1302 series includes additional features such as NVSRAM and trickle-charger functionality without requiring circuit modifications.

S-35192A-I8T1U from ABLIC Inc. provides an alternative 3-wire serial solution with 698 units in stock. This part extends the supply voltage range to 1.3V ~ 5.5V and includes alarm functionality. Timekeeping current is higher at 8µA ~ 14µA, making it suitable for applications where lower power consumption is not critical.

For SPI Interface Substitutes (Design Modification Required):

DS1343E-33+ and DS1343E-33+T&R are active products offering SPI interface with expanded 96B memory and additional features including alarm and square wave output. These parts require firmware and circuit redesign due to interface change. DS1343E-33+ is available in tube packaging (1,209 units), while DS1343E-33+T&R is available in tape and reel (1,014 units). Both support 12/24-hour time format and operate within the required temperature range.

DS1344E-3+ provides an active alternative with SPI interface, 96B memory, and similar feature set. With 1,910 units in stock, this part offers good availability. DS1344D-18+T&R is an obsolete option and should be avoided for new designs.

Compliance and Availability:

All substitute parts maintain ROHS3 compliance and MSL rating of 1 (Unlimited). Active product status is preferred for long-term supply assurance. DS1302SN+T&R offers the highest inventory level (30,200 units) among 3-wire serial options, ensuring supply continuity.

Frequently Asked Questions (FAQ)

Q: Can DS1302SN+T&R directly replace RTC-4543SA:B3:PURE SN without circuit modification?

A: Yes. DS1302SN+T&R maintains the 3-wire serial interface, supports identical time and date formats (HH:MM:SS and YY-MM-DD-dd), and operates within the same temperature range (-40°C to 85°C). Pin configuration and signal timing must be verified against the original design, but no interface conversion is required.

Q: What is the key difference between DS1302SN+T&R and DS1302ZN+?

A: Both parts are functionally equivalent with identical electrical specifications. The primary difference is packaging: DS1302SN+T&R is supplied in cut tape and digi-reel format suitable for automated assembly, while DS1302ZN+ is supplied in tube format. DS1302SN+T&R has significantly higher inventory availability (30,200 units vs. 1,217 units).

Q: Why do DS1343E-33+ and DS1344E-3+ require design modification?

A: These parts use SPI interface instead of 3-wire serial. SPI requires different signal lines (MOSI, MISO, CLK, CS) compared to the 3-wire serial protocol (CLK, DATA, CE). Microcontroller firmware and PCB routing must be redesigned to accommodate the interface change.

Q: How does timekeeping current consumption affect part selection?

A: DS1302 series parts (0.3µA ~ 1µA) consume significantly less current during timekeeping than the original RTC-4543SA (1µA ~ 3µA) and S-35192A-I8T1U (8µA ~ 14µA). For battery-backed applications, lower consumption extends backup battery life. DS1343 and DS1344 series parts consume 120µA ~ 160µA and are suitable only for applications where continuous power is available.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts maintain ROHS3 compliance and MSL rating of 1 (Unlimited), meeting environmental and reliability standards equivalent to the original component.

Q: What is the supply voltage compatibility range for substitutes?

A: DS1302 series parts operate at 2V ~ 5.5V, which overlaps with the original part's 2.5V ~ 5.5V range. S-35192A-I8T1U extends to 1.3V ~ 5.5V. DS1343 and DS1344 series parts operate at 3V ~ 5.5V and 2.7V ~ 5.5V respectively, which may not support 2.5V applications. Verify supply voltage requirements before selection.

Q: Can S-35192A-I8T1U be used as a direct replacement?

A: S-35192A-I8T1U maintains 3-wire serial interface and supports the required time/date formats. However, timekeeping current is higher (8µA ~ 14µA vs. 1µA ~ 3µA), and package type differs (8-SMD flat lead vs. 14-SOIC). Use only if power consumption increase is acceptable and PCB layout accommodates the different package.

Q: Which substitute offers the best long-term availability?

A: DS1302SN+T&R is the recommended choice for long-term availability. It is an active product with the highest inventory level (30,200 units), ensuring supply continuity for production and maintenance applications.