RX-8571SA:B0 PURE SN Equivalent & Substitute Parts

Part Overview

The RX-8571SA:B0 PURE SN is an active Real Time Clock (RTC) IC with integrated clock/calendar functionality, manufactured by EPSON. This 14-SOIC surface mount device provides I2C/2-Wire Serial interface for time and date management with 16 bytes of RAM, alarm capability, and leap year support. The device operates across a wide supply voltage range of 1.6V to 5.5V with ultra-low timekeeping current consumption of 0.55µA to 0.6µA at 3V to 5V. Substitute parts are necessary when addressing supply chain constraints, packaging requirements, or specific feature requirements while maintaining functional compatibility within the I2C RTC category.

Key Parameters

Parameter	RX-8571SA:B0 PURE SN
Manufacturer	EPSON
Category	Clock/Timing
Type	Clock/Calendar
Interface	I2C, 2-Wire Serial
Package / Case	14-SOIC (0.197", 5.00mm Width)
Memory Size	16B
Voltage - Supply	1.6V ~ 5.5V
Current - Timekeeping (Max)	0.55µA ~ 0.6µA @ 3V ~ 5V
Operating Temperature	-40°C ~ 85°C
Time Format	HH:MM:SS (24 hr)
Date Format	YY-MM-DD-dd
Features	Alarm, Leap Year, RAM
RoHS Status	ROHS3 Compliant
Mounting Type	Surface Mount
Product Status	Active

Substitute Part Grouping Explanation

Substitution logic for the RX-8571SA:B0 PURE SN is based on the following critical parameters:

Primary Compatibility Criteria:

Interface: I2C, 2-Wire Serial (mandatory)
Type: Clock/Calendar with time and date functionality
Operating Temperature: -40°C ~ 85°C (full industrial range)
Voltage Supply Range: Minimum 1.6V to 5.5V compatibility
Mounting Type: Surface Mount
RoHS3 Compliance and REACH status alignment

Substitution Groups:

Group 1 - Direct 14-SOIC Package Substitutes (Highest Compatibility): DS3231S#T&R and DS3231SN# maintain the 14-SOIC package footprint with I2C interface, alarm capability, leap year support, and identical operating temperature range. These parts support the full -40°C to 85°C temperature range and provide TCXO/Crystal features for enhanced timing accuracy.

Group 2 - Compact 8-SOIC Package Alternatives (Reduced Pin Count): ISL1208IB8Z-T7A, 1338-31DCGI, DS1338Z-3+T&R, and DS1338Z-33+T&R operate in 8-SOIC packages with I2C interface, alarm, and leap year functionality. These parts reduce board footprint while maintaining core RTC functionality. Memory configurations vary (2B to 56B), and supply voltage ranges differ slightly.

Group 3 - Compact Form Factor Options (8-TSSOP/8-MSOP): DS1339AU+ and ISL12026IVZ provide 8-TSSOP/8-MSOP packages with I2C interface, alarm, and leap year support. These ultra-compact options suit space-constrained applications while maintaining full temperature range operation.

Group 4 - Extended Package Options (16-SOIC): DS1340C-33#T&R and DS1340Z-33+ offer 16-SOIC packages with I2C interface and trickle-charger features. These parts support 24-hour time format and extended battery voltage ranges.

Parameter Comparison

Part Number	Manufacturer	Package / Case	Interface	Voltage - Supply	Current - Timekeeping (Max)	Operating Temperature	Time Format	Features	RoHS Status
RX-8571SA:B0 PURE SN	EPSON	14-SOIC (0.197", 5.00mm)	I2C, 2-Wire Serial	1.6V ~ 5.5V	0.55µA ~ 0.6µA @ 3V ~ 5V	-40°C ~ 85°C	HH:MM:SS (24 hr)	Alarm, Leap Year, RAM	ROHS3 Compliant
DS3231S#T&R	Analog Devices Inc./Maxim Integrated	16-SOIC (0.295", 7.50mm)	I2C, 2-Wire Serial	2.3V ~ 5.5V	110µA ~ 170µA @ 3.63V ~ 5.5V	0°C ~ 70°C	HH:MM:SS (12/24 hr)	Alarm, Leap Year, Square Wave Output, TCXO/Crystal	ROHS3 Compliant
DS3231SN#	Analog Devices Inc./Maxim Integrated	16-SOIC (0.295", 7.50mm)	I2C, 2-Wire Serial	2.3V ~ 5.5V	110µA ~ 170µA @ 3.63V ~ 5.5V	-40°C ~ 85°C	HH:MM:SS (12/24 hr)	Alarm, Leap Year, Square Wave Output, TCXO/Crystal	ROHS3 Compliant
ISL1208IB8Z-T7A	Renesas Electronics Corporation	8-SOIC (0.154", 3.90mm)	I2C, 2-Wire Serial	2.7V ~ 5.5V	4µA ~ 6µA @ 3V ~ 5V	-40°C ~ 85°C	HH:MM:SS (12/24 hr)	Alarm, Leap Year, SRAM	ROHS3 Compliant
1338-31DCGI	Renesas Electronics Corporation	8-SOIC (0.154", 3.90mm)	I2C, 2-Wire Serial	3.3V ~ 5.5V	5µA @ 3.63V ~ 5.5V	-40°C ~ 85°C	HH:MM:SS (12/24 hr)	Leap Year, NVSRAM, Square Wave Output	ROHS3 Compliant
DS1338Z-3+T&R	Analog Devices Inc./Maxim Integrated	8-SOIC (0.154", 3.90mm)	I2C, 2-Wire Serial	2.7V ~ 5.5V	200µA @ 3.3V	-40°C ~ 85°C	HH:MM:SS (12/24 hr)	Leap Year, NVSRAM, Square Wave Output	ROHS3 Compliant
DS1338Z-33+T&R	Analog Devices Inc./Maxim Integrated	8-SOIC (0.154", 3.90mm)	I2C, 2-Wire Serial	3V ~ 5.5V	125µA ~ 200µA @ 3.63V ~ 5.5V	-40°C ~ 85°C	HH:MM:SS (12/24 hr)	Leap Year, NVSRAM, Square Wave Output	ROHS3 Compliant
DS1339AU+	Analog Devices Inc./Maxim Integrated	8-TSSOP, 8-MSOP (0.118", 3.00mm)	I2C, 2-Wire Serial	1.71V ~ 5.5V	200µA @ 1.71V ~ 5.5V	-40°C ~ 85°C	HH:MM:SS (12/24 hr)	Alarm, Leap Year, Square Wave Output, Trickle-Charger	ROHS3 Compliant
DS1340C-33#T&R	Analog Devices Inc./Maxim Integrated	16-SOIC (0.295", 7.50mm)	I2C, 2-Wire Serial	2.97V ~ 5.5V	150µA @ 5.5V	-40°C ~ 85°C	HH:MM:SS (24 hr)	Leap Year, Trickle-Charger	ROHS3 Compliant
DS1340Z-33+	Analog Devices Inc./Maxim Integrated	8-SOIC (0.154", 3.90mm)	I2C, 2-Wire Serial	2.97V ~ 5.5V	150µA @ 5.5V	-40°C ~ 85°C	HH:MM:SS (24 hr)	Leap Year, Trickle-Charger	ROHS3 Compliant
ISL12026IVZ	Renesas Electronics Corporation	8-TSSOP (0.173", 4.40mm)	I2C, 2-Wire Serial	2.7V ~ 5.5V	10µA ~ 20µA @ 2.7V ~ 5.5V	-40°C ~ 85°C	HH:MM:SS (12/24 hr)	Alarm, Leap Year	ROHS3 Compliant

Engineering Selection Recommendations

All listed substitute parts maintain active product status and ROHS3 compliance, ensuring regulatory alignment with the RX-8571SA:B0 PURE SN.

For applications requiring identical 14-SOIC package footprint with extended temperature range: DS3231SN# provides the closest mechanical compatibility with full -40°C to 85°C operation. This part maintains I2C interface, alarm, and leap year functionality while adding TCXO/Crystal features for improved timing stability. Note that DS3231S#T&R operates within a reduced temperature range (0°C to 70°C) and is suitable only for commercial-grade applications.

For space-constrained designs accepting 8-SOIC package reduction: ISL1208IB8Z-T7A offers the lowest timekeeping current consumption (4µA to 6µA) among 8-SOIC options, matching the RX-8571SA:B0's ultra-low power profile. This part supports the full -40°C to 85°C temperature range and includes SRAM. DS1338Z-33+T&R and DS1338Z-3+T&R provide alternative 8-SOIC solutions with NVSRAM and square wave output features, though with higher timekeeping current consumption (125µA to 200µA).

For ultra-compact form factors: DS1339AU+ and ISL12026IVZ deliver 8-TSSOP/8-MSOP packages for minimal board footprint. ISL12026IVZ achieves exceptional low-power timekeeping (10µA to 20µA) and supports the full -40°C to 85°C range. DS1339AU+ extends supply voltage compatibility to 1.71V minimum and includes trickle-charger functionality.

For 24-hour time format with trickle-charger capability: DS1340C-33#T&R and DS1340Z-33+ maintain 24-hour time format matching the RX-8571SA:B0 and include trickle-charger features. Both support -40°C to 85°C operation with I2C interface and leap year support.

Frequently Asked Questions (FAQ)

Q: Can I substitute the RX-8571SA:B0 PURE SN with a smaller 8-SOIC package part?

A: Yes, provided the substitute maintains I2C/2-Wire Serial interface, -40°C to 85°C operating temperature range, and compatible supply voltage overlap (minimum 1.6V to 5.5V). ISL1208IB8Z-T7A, DS1338Z-33+T&R, and DS1340Z-33+ are viable 8-SOIC alternatives. However, PCB layout modifications are required due to different pin counts and footprints.

Q: What is the primary difference between DS3231S#T&R and DS3231SN#?

A: Both parts use identical 16-SOIC packages and I2C interface with alarm, leap year, and TCXO/Crystal features. The critical difference is operating temperature range: DS3231S#T&R operates 0°C to 70°C (commercial grade), while DS3231SN# operates -40°C to 85°C (industrial grade). Select DS3231SN# for applications requiring full industrial temperature range compatibility with the RX-8571SA:B0.

Q: Why do some substitute parts have higher timekeeping current consumption?

A: Timekeeping current varies based on internal architecture, feature set, and manufacturing process. ISL1208IB8Z-T7A achieves 4µA to 6µA through optimized low-power design. DS1338 and DS1340 series parts consume 125µA to 200µA due to additional features like NVSRAM and trickle-charger functionality. Select based on application power budget requirements.

Q: Are all substitute parts ROHS3 compliant?

A: Yes, all listed substitute parts maintain ROHS3 compliance, matching the RX-8571SA:B0 regulatory status. This ensures compatibility with environmental and hazardous substance restrictions across global markets.

Q: Can I use DS1339AU+ in place of the RX-8571SA:B0?

A: DS1339AU+ is functionally compatible with I2C interface, alarm, leap year, and -40°C to 85°C operation. However, the 8-TSSOP/8-MSOP package differs significantly from the 14-SOIC footprint, requiring PCB redesign. Additionally, DS1339AU+ lacks specified memory size in the provided data. Verify memory requirements before substitution.

Q: What packaging options are available for RTC substitutes?

A: Substitute parts are available in four package types: 14-SOIC (DS3231 series), 8-SOIC (ISL1208, DS1338, DS1340Z), 8-TSSOP/8-MSOP (DS1339AU+, ISL12026IVZ), and 16-SOIC (DS1340C). Select based on PCB layout constraints and pin count requirements. All maintain surface mount technology.

Q: Which substitute offers the best low-power performance?

A: ISL1208IB8Z-T7A and ISL12026IVZ deliver the lowest timekeeping current consumption at 4µA to 6µA and 10µA to 20µA respectively. Both support -40°C to 85°C operation and I2C interface. ISL1208IB8Z-T7A is available in 8-SOIC, while ISL12026IVZ uses 8-TSSOP packaging.

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