PCF2131TFY Equivalent & Substitute Parts

Part Overview

The PCF2131TFY is an active Real Time Clock (RTC) IC manufactured by NXP USA Inc., designed for clock/calendar applications requiring I2C and SPI interface support. This 16-LFDFN Exposed Pad surface mount device integrates timekeeping, alarm, leap year, SRAM, and watchdog timer functionality across a wide supply voltage range of 1.2V to 5.5V. The part is ROHS3 compliant and currently in active production status with 3300 units in stock.

Equivalent and substitute parts are identified based on functional compatibility within the Clock/Calendar IC category. Substitutes must support comparable timekeeping features, interface protocols, operating temperature ranges, and compliance certifications to ensure direct replacement capability in system designs.

Key Parameters

Parameter	PCF2131TFY
Manufacturer	NXP USA Inc.
Category	Clock/Timing
Type	Clock/Calendar
Interface	I2C, SPI
Memory Size	8B
Time Format	HH:MM:SS:hh (12/24 hr)
Date Format	YY-MM-DD-dd
Voltage - Supply	1.2V ~ 5.5V
Voltage - Supply, Battery	1.2V ~ 5.5V
Current - Timekeeping (Max)	770nA ~ 2.135µA @ 1.2V ~ 5.5V
Operating Temperature	-40°C ~ 85°C
Features	Alarm, Leap Year, SRAM, Watchdog Timer
Package / Case	16-LFDFN Exposed Pad
Mounting Type	Surface Mount, Wettable Flank
RoHS Status	ROHS3 Compliant
Product Status	Active

Substitute Part Grouping Explanation

Substitute parts for the PCF2131TFY are selected based on the following critical parameters that determine functional compatibility:

Interface Compatibility: All substitute parts support I2C and/or 2-Wire Serial protocols, enabling direct communication protocol compatibility with systems designed for the PCF2131TFY.

Timekeeping Functionality: All substitutes provide Clock/Calendar functionality with HH:MM:SS time format and YY-MM-DD-dd date format, maintaining core timekeeping accuracy and date tracking capabilities.

Operating Temperature Range: All substitute parts operate across the -40°C to 85°C temperature range, ensuring thermal compatibility in equivalent application environments.

Feature Set: Substitute parts include Alarm and Leap Year functionality as baseline features, with several options providing additional SRAM, Square Wave Output, and Watchdog Timer capabilities.

Supply Voltage Range: Substitute parts operate within overlapping or compatible voltage ranges (1.8V to 5.5V minimum across the group), supporting both primary and battery-backed operation modes.

Compliance Certifications: All substitute parts maintain ROHS3 compliance and EAR99 ECCN classification, ensuring regulatory equivalence for procurement and deployment.

Product Status: All substitute parts are in active production status, guaranteeing availability and long-term supply continuity.

Parameter Comparison

Parameter	PCF2131TFY	DS1338U-33+T&R	ISL12058IRTZ-T	ISL1208IU8Z-TK	M41ST87WSS6F	MCP7940M-I/SN	MCP79410-I/MS	RX-8564LC:B0 PURE SN
Manufacturer	NXP USA Inc.	Analog Devices Inc./Maxim Integrated	Renesas Electronics Corporation	Renesas Electronics Corporation	STMicroelectronics	Microchip Technology	Microchip Technology	EPSON
Type	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar
Interface	I2C, SPI	I2C, 2-Wire Serial	I2C, 2-Wire Serial	I2C, 2-Wire Serial	I2C, 2-Wire Serial	I2C, 2-Wire Serial	I2C, 2-Wire Serial	I2C, 2-Wire Serial
Time Format	HH:MM:SS:hh (12/24 hr)	HH:MM:SS (12/24 hr)	HH:MM:SS (12/24 hr)	HH:MM:SS (12/24 hr)	HH:MM:SS:hh (24 hr)	HH:MM:SS (12/24 hr)	HH:MM:SS (12/24 hr)	HH:MM:SS (24 hr)
Date Format	YY-MM-DD-dd	YY-MM-DD-dd	YY-MM-DD-dd	YY-MM-DD-dd	YY-MM-DD-dd	YY-MM-DD-dd	YY-MM-DD-dd	YY-MM-DD-dd
Voltage - Supply	1.2V ~ 5.5V	3V ~ 5.5V	1.8V ~ 3.6V	2.7V ~ 5.5V	2.7V ~ 3.6V	1.8V ~ 5.5V	1.8V ~ 5.5V	1.8V ~ 5.5V
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Features	Alarm, Leap Year, SRAM, Watchdog Timer	Leap Year, NVSRAM, Square Wave Output	Alarm, Leap Year	Alarm, Leap Year, SRAM	Alarm, Leap Year, NVSRAM, Square Wave Output, Supervisor, Watchdog Timer	Alarm, Leap Year, Square Wave Output, SRAM	Alarm, Leap Year, Square Wave Output, SRAM, Unique ID	Alarm, Leap Year
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Active	Active	Active	Active	Active	Active	Active	Active

Engineering Selection Recommendations

Primary Substitutes (Highest Compatibility):

The ISL1208IU8Z-TK, MCP79410-I/MS, and MCP7940M-I/SN are primary substitutes offering the closest functional alignment with the PCF2131TFY. These parts provide I2C interface, Alarm and Leap Year features, SRAM capability, and operate across the -40°C to 85°C temperature range. All three maintain ROHS3 compliance and active product status. The ISL1208IU8Z-TK offers the lowest timekeeping current consumption at 4µA to 6µA, while MCP79410-I/MS provides extended memory (64B, 1Kb) and unique ID functionality.

Secondary Substitutes (Feature-Enhanced Options):

The M41ST87WSS6F provides enhanced functionality including Supervisor and Watchdog Timer capabilities alongside Alarm, Leap Year, and NVSRAM features. This part operates within a narrower supply voltage range (2.7V to 3.6V) and is suitable for applications requiring additional system monitoring. The DS1338U-33+T&R offers NVSRAM and Square Wave Output with a minimum supply voltage of 3V, appropriate for 3.3V and 5V system designs.

Specialized Substitutes (Low-Power Applications):

The ISL12058IRTZ-T and RX-8564LC:B0 PURE SN are optimized for ultra-low-power timekeeping applications, with current consumption of 0.65µA at 1.8V and 0.65µA to 0.8µA at 2V to 5V respectively. These parts are suitable for battery-backed or energy-constrained applications where minimizing standby current is critical.

Compliance and Availability:

All substitute parts maintain ROHS3 compliance and EAR99 ECCN classification, ensuring regulatory equivalence. Inventory levels range from 1270 to 41200 units across the substitute options, providing supply flexibility. The RX-8564LC:B0 PURE SN carries REACH Affected status, requiring verification for applications subject to REACH regulations.

Frequently Asked Questions (FAQ)

Q: Can the ISL1208IU8Z-TK directly replace the PCF2131TFY in all applications?

A: The ISL1208IU8Z-TK provides I2C interface, Alarm, Leap Year, and SRAM features compatible with the PCF2131TFY. However, the PCF2131TFY supports both I2C and SPI interfaces, while the ISL1208IU8Z-TK supports only I2C and 2-Wire Serial. Applications requiring SPI interface must use an alternative substitute or retain the original part. The ISL1208IU8Z-TK operates at 2.7V to 5.5V supply voltage, which overlaps with the PCF2131TFY range but does not extend to the 1.2V minimum of the original part.

Q: What is the primary difference between the MCP79410-I/MS and MCP7940M-I/SN?

A: Both parts are manufactured by Microchip Technology and provide equivalent Clock/Calendar functionality with Alarm, Leap Year, Square Wave Output, and SRAM features. The MCP79410-I/MS offers extended memory (64B, 1Kb) and includes a Unique ID feature, making it suitable for applications requiring device identification. The MCP7940M-I/SN provides 64B memory without the Unique ID feature. Both operate across 1.8V to 5.5V supply voltage and -40°C to 85°C temperature range.

Q: Why does the M41ST87WSS6F have a narrower supply voltage range than the PCF2131TFY?

A: The M41ST87WSS6F is designed for 2.7V to 3.6V supply operation, reflecting its optimization for 3.3V system designs with integrated Supervisor and Watchdog Timer functionality. Applications requiring the full 1.2V to 5.5V range of the PCF2131TFY should select alternatives such as the MCP79410-I/MS or MCP7940M-I/SN, which support the extended voltage range.

Q: What packaging considerations apply when substituting the PCF2131TFY?

A: The PCF2131TFY uses a 16-LFDFN Exposed Pad package. Substitute parts employ different packages: DS1338U-33+T&R uses 8-TSSOP/8-MSOP, ISL12058IRTZ-T uses 8-WDFN, ISL1208IU8Z-TK uses 8-TSSOP/8-MSOP, M41ST87WSS6F uses 20-SSOP, MCP7940M-I/SN uses 8-SOIC, MCP79410-I/MS uses 8-TSSOP/8-MSOP, and RX-8564LC:B0 PURE SN uses 12-TFSOJ. PCB layout modifications are required for any package change. Pin-to-pin compatibility does not exist across these packages; firmware or software interface adjustments may be necessary depending on I2C address and register map differences.

Q: Which substitute offers the lowest power consumption for battery-backed operation?

A: The RX-8564LC:B0 PURE SN and ISL12058IRTZ-T both provide ultra-low timekeeping current consumption. The ISL12058IRTZ-T operates at 0.65µA at 1.8V, while the RX-8564LC:B0 PURE SN operates at 0.65µA to 0.8µA across 2V to 5V. Both are suitable for extended battery-backed timekeeping applications. The PCF2131TFY provides 770nA to 2.135µA across its full voltage range, offering comparable low-power performance.

Q: Are all substitute parts available in the same packaging options as the PCF2131TFY?

A: No. The PCF2131TFY is available in Cut Tape (CT) and Digi-Reel packaging. Substitute parts are available in various packaging formats: DS1338U-33+T&R in Cut Tape and Digi-Reel, ISL12058IRTZ-T in Tape & Reel, ISL1208IU8Z-TK in Cut Tape and Digi-Reel, M41ST87WSS6F in Cut Tape and Digi-Reel, MCP7940M-I/SN in Tube, MCP79410-I/MS in Tube, and RX-8564LC:B0 PURE SN in Tape & Reel. Packaging selection affects procurement logistics and handling requirements.

Q: What is the significance of ROHS3 compliance for all substitute parts?

A: ROHS3 compliance indicates that all substitute parts meet Restriction of Hazardous Substances Directive requirements, restricting lead, cadmium, mercury, and other hazardous materials. This compliance status ensures that substitute parts are suitable for deployment in applications subject to ROHS regulations, including consumer electronics and European market applications. All listed substitutes maintain ROHS3 compliance, ensuring regulatory equivalence with the PCF2131TFY.

Q: Can the DS1338U-33+T&R be used in applications requiring the full 1.2V to 5.5V supply range?

A: No. The DS1338U-33+T&R operates at 3V to 5.5V supply voltage, which does not extend to the 1.2V minimum of the PCF2131TFY. Applications requiring operation below 3V supply voltage must select alternatives such as the MCP79410-I/MS, MCP7940M-I/SN, ISL1208IU8Z-TK, or RX-8564LC:B0 PURE SN, all of which support 1.8V minimum supply voltage or lower.

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