RTC-4574SA:B3:PURE SN Equivalent & Substitute Parts

Part Overview

The RTC-4574SA:B3:PURE SN is a Real Time Clock (RTC) IC manufactured by EPSON, designed for clock/calendar applications with 3-wire serial interface capability. This component is classified as obsolete, making equivalent and substitute parts necessary for new designs, production continuity, and system upgrades. The part operates across a wide supply voltage range of 1.6V to 5.5V with minimal timekeeping current consumption of 1µA to 2µA at 3V to 5V, housed in a 14-SOIC package.

Substiute Parts

RTC-4574SA:B3:PURE SN

EPSONIn Stock: 769RTC-4574SA:B3:PURE SN Datasheet

Current PartRFQ

DS1302SN+T&R

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

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DS1306E+

Analog Devices Inc./Maxim IntegratedIn Stock: 2857DS1306E+ Datasheet

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DS1306E+T&R

Analog Devices Inc./Maxim IntegratedIn Stock: 3744DS1306E+T&R Datasheet

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DS1306EN+

Analog Devices Inc./Maxim IntegratedIn Stock: 3213DS1306EN+ Datasheet

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DS1344D-33+

Analog Devices Inc./Maxim IntegratedIn Stock: 891DS1344D-33+ Datasheet

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DS1344E-3+

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

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DS1392U-33+

Analog Devices Inc./Maxim IntegratedIn Stock: 1081DS1392U-33+ Datasheet

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PT7C43190AWEX

Diodes IncorporatedIn Stock: 1066PT7C43190AWEX Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the RTC-4574SA:B3:PURE SN is determined by the following critical parameters:

• Interface Type: 3-Wire Serial protocol compatibility
• Supply Voltage Range: Minimum 1.6V support for low-power applications
• Operating Temperature Range: -40°C to 85°C industrial grade
• Package Compatibility: Surface mount form factor with similar pin density
• Timekeeping Current: Low-power operation for battery-backed applications
• Compliance: ROHS3 compliance and MSL rating

Substitute parts are grouped into two categories based on interface protocol:

Category 1 - 3-Wire Serial Interface (Direct Protocol Match)

• DS1302SN+T&R
• DS1392U-33+
• PT7C43190AWEX

Category 2 - SPI Interface (Protocol Variation)

• DS1306E+
• DS1306E+T&R
• DS1306EN+
• DS1344D-33+
• DS1344E-3+

Parts in Category 1 maintain the original 3-wire serial protocol. Parts in Category 2 utilize SPI protocol, requiring firmware or hardware interface modifications but offering enhanced features and memory capacity.

Parameter Comparison

Engineering Selection Recommendations

For Direct Protocol Compatibility (3-Wire Serial)

DS1302SN+T&R is the primary substitute when maintaining 3-wire serial protocol is required. This part is active in production, ROHS3 compliant, and operates across -40°C to 85°C. The supply voltage range of 2V to 5.5V covers most applications, though the lower limit is 0.4V higher than the original part. Timekeeping current is superior at 0.3µA to 1µA. Package footprint differs (8-SOIC vs. 14-SOIC), requiring PCB layout modification.

PT7C43190AWEX from Diodes Incorporated offers the lowest supply voltage floor at 1.35V, closest to the original 1.6V specification. This part maintains 3-wire serial protocol, operates across the full -40°C to 85°C range, and is ROHS3 compliant. The 8-SOIC package requires PCB redesign similar to DS1302SN+T&R.

DS1392U-33+ provides 3-wire serial interface with -40°C to 85°C operation and ROHS3 compliance. However, timekeeping current of 175µA is significantly higher than the original specification, making this option suitable only for applications where power consumption is not critical.

For SPI Protocol Implementation

DS1306EN+ is recommended for applications where SPI protocol can be accommodated. This part operates across -40°C to 85°C, matching the original temperature range, and is ROHS3 compliant. The 20-TSSOP package requires significant PCB layout changes. Operating current of 25.3µA to 81µA is higher than the original part.

DS1306E+ and DS1306E+T&R are functionally identical to DS1306EN+ but with reduced operating temperature range (0°C to 70°C), limiting use in industrial applications requiring full -40°C to 85°C operation.

DS1344D-33+ and DS1344E-3+ offer SPI interface with enhanced features and -40°C to 85°C operation. Both are ROHS3 compliant. Package options (14-WFDFN and 20-TSSOP respectively) require PCB redesign.

Frequently Asked Questions (FAQ)

Q: Can DS1302SN+T&R directly replace RTC-4574SA:B3:PURE SN without firmware changes?

A: DS1302SN+T&R maintains 3-wire serial protocol compatibility, eliminating firmware modifications. However, PCB layout changes are required due to different package footprints (8-SOIC vs. 14-SOIC) and pin configurations. Verify pinout compatibility before implementation.

Q: What is the primary limitation of using SPI-based substitutes like DS1306EN+?

A: SPI-based substitutes require hardware interface modifications and firmware rewrite to support the SPI protocol instead of 3-wire serial. Applications using 3-wire serial protocol cannot use these parts without complete interface redesign.

Q: Why does PT7C43190AWEX have a lower supply voltage minimum than other substitutes?

A: PT7C43190AWEX from Diodes Incorporated is designed with a lower voltage threshold of 1.35V, providing compatibility with ultra-low-power battery-backed applications. This specification approaches the original RTC-4574SA:B3:PURE SN minimum of 1.6V more closely than competing alternatives.

Q: Is operating temperature range critical for substitute selection?

A: Operating temperature range is critical for industrial and automotive applications. DS1306E+ and DS1306E+T&R are limited to 0°C to 70°C, unsuitable for -40°C to 85°C environments. All other substitutes support the full -40°C to 85°C range matching the original part.

Q: What are the implications of higher timekeeping current in substitute parts?

A: Higher timekeeping current directly impacts battery life in battery-backed RTC applications. DS1392U-33+ at 175µA will deplete backup batteries significantly faster than the original 1µA to 2µA specification. For battery-critical applications, DS1302SN+T&R (0.3µA to 1µA) or PT7C43190AWEX (0.6µA to 14µA) are preferred.

Q: Are all substitute parts ROHS3 compliant?

A: Yes, all listed substitute parts are ROHS3 compliant with MSL rating of 1 (Unlimited), matching the original part's environmental compliance profile.

Q: What package considerations apply when selecting a substitute?

A: The original RTC-4574SA:B3:PURE SN uses 14-SOIC packaging. All substitutes use different packages (8-SOIC, 10-TFSOP, or 20-TSSOP), requiring PCB layout redesign, new footprints, and potential trace routing modifications. Pin-to-pin compatibility cannot be assumed.