MCP79412T-I/ST Equivalent & Substitute Parts

Part Overview

The MCP79412T-I/ST is a Real Time Clock (RTC) IC with integrated Clock/Calendar functionality manufactured by Microchip Technology. This device operates as a 64-byte, 1-kilobyte I2C 2-Wire Serial interface component in an 8-TSSOP surface mount package. The MCP79412T-I/ST is classified as an Active product with ROHS3 compliance and unlimited moisture sensitivity rating.

Substitute parts are identified when equivalent electrical and mechanical parameters align with the main device specifications, enabling direct replacement in applications requiring RTC Clock/Calendar functionality with I2C interface compatibility.

Key Parameters

Parameter	MCP79412T-I/ST
Manufacturer	Microchip Technology
Category	Clock/Timing
Type	Clock/Calendar
Interface	I2C, 2-Wire Serial
Memory Size	64B, 1Kb
Time Format	HH:MM:SS (12/24 hr)
Date Format	YY-MM-DD-dd
Voltage - Supply	1.8V ~ 5.5V
Voltage - Supply, Battery	1.3V ~ 5.5V
Current - Timekeeping (Max)	1.2µA @ 3.3V
Operating Temperature	-40°C ~ 85°C
Mounting Type	Surface Mount
Package / Case	8-TSSOP (0.173", 4.40mm Width)
Features	Alarm, Leap Year, Square Wave Output, SRAM, Unique ID
Product Status	Active
RoHS Status	ROHS3 Compliant
MSL Rating	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the MCP79412T-I/ST is determined by the following critical parameters:

Primary Compatibility Criteria:

Interface: I2C, 2-Wire Serial (mandatory)
Type: Clock/Calendar (mandatory)
Operating Temperature: -40°C ~ 85°C (mandatory)
Time Format: HH:MM:SS with 12/24 hour support (required)
Date Format: YY-MM-DD-dd (required)
Voltage Supply Range: Overlap with 1.8V ~ 5.5V (required)
Product Status: Active (required)
RoHS Compliance: ROHS3 Compliant (required)

Secondary Compatibility Considerations:

Memory Size: 64B minimum for functional equivalence
Current Consumption: Lower or equivalent timekeeping current preferred
Package Type: Surface mount variants acceptable (8-TSSOP, 8-MSOP, 8-SOIC, 12-VSOJ, 14-SOP, 16-SO, 20-SOIC)
Features: Alarm and Leap Year support (standard across substitutes)

Substitute parts are grouped by package compatibility and electrical parameter alignment. All identified substitutes maintain I2C interface compatibility, support both 12/24-hour time formats, and operate within the -40°C to 85°C temperature range.

Parameter Comparison

Parameter	MCP79412T-I/ST	DS1308U-33+T	DS1338Z-18+	DS1340Z-33+	ISL12008IB8Z-T	ISL12022MAIBZ-T	ISL12058IUZ-T	PCF2127T/2Y	RX-8571LCB0	RX-8803LC:UB3	RX8900SA:UB3
Manufacturer	Microchip Technology	Analog Devices Inc./Maxim Integrated	Analog Devices Inc./Maxim Integrated	Analog Devices Inc./Maxim Integrated	Renesas Electronics Corporation	Renesas Electronics Corporation	Renesas Electronics Corporation	NXP USA Inc.	EPSON	EPSON	EPSON
Type	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar	Clock/Calendar
Interface	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	I2C, 2-Wire Serial	I2C, 2-Wire Serial	I2C, 2-Wire Serial	I2C
Time Format	HH:MM:SS (12/24 hr)	HH:MM:SS (12/24 hr)	HH:MM:SS (12/24 hr)	HH:MM:SS (24 hr)	HH:MM:SS:hh (24 hr)	HH:MM:SS (12/24 hr)	HH:MM:SS (12/24 hr)	HH:MM:SS (12/24 hr)	HH:MM:SS (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	YY-MM-DD-dd	YY-MM-DD	YY-MM-DD-dd
Voltage - Supply	1.8V ~ 5.5V	3V ~ 5.5V	1.71V ~ 5.5V	2.97V ~ 5.5V	2.7V ~ 5.5V	2.7V ~ 5.5V	1.8V ~ 3.6V	1.8V ~ 4.2V	1.6V ~ 5.5V	1.6V ~ 5.5V	2.5V ~ 5.5V
Voltage - Supply, Battery	1.3V ~ 5.5V	1.3V ~ 5.5V	1.3V ~ 3.7V	1.3V ~ 5.5V	1.8V ~ 5.5V	1.8V ~ 5.5V	-	1.8V ~ 4.2V	-	-	1.6V ~ 5.5V
Current - Timekeeping (Max)	1.2µA @ 3.3V	125µA ~ 200µA @ 3V ~ 5.5V	100µA @ 1.89V	150µA @ 5.5V	4µA ~ 6µA @ 3V ~ 5V	14µA ~ 15µA @ 3V ~ 5V	0.65µA @ 1.8V	1.5µA @ 3.3V	0.55µA ~ 0.6µA @ 3V ~ 5V	2.1µA ~ 3.4µA @ 3V ~ 5V	1.4µA ~ 1.5µA @ 3V ~ 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	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	8-TSSOP (0.173", 4.40mm Width)	8-TSSOP, 8-MSOP (0.118", 3.00mm Width)	8-SOIC (0.154", 3.90mm Width)	8-SOIC (0.154", 3.90mm Width)	8-SOIC (0.154", 3.90mm Width)	20-SOIC (0.295", 7.50mm Width)	8-TSSOP, 8-MSOP (0.118", 3.00mm Width)	16-SOIC (0.295", 7.50mm Width)	12-TFSOJ (0.094", 2.40mm Width)	12-TFSOJ (0.094", 2.40mm Width)	14-SOIC (0.197", 5.00mm Width)
Product Status	Active	Active	Active	Active	Active	Active	Active	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
MSL Rating	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	3 (168 Hours)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

All substitute parts listed maintain Active product status and ROHS3 compliance, meeting regulatory requirements equivalent to the MCP79412T-I/ST. Selection among substitutes depends on specific application constraints:

Package-Constrained Applications: DS1308U-33+T and ISL12058IUZ-T offer 8-TSSOP/8-MSOP packages matching the original footprint. DS1338Z-18+, DS1340Z-33+, and ISL12008IB8Z-T provide 8-SOIC alternatives with comparable pin counts.

Low-Power Applications: ISL12058IUZ-T (0.65µA @ 1.8V), RX-8571LCB0 (0.55µA ~ 0.6µA @ 3V ~ 5V), and PCF2127T/2Y (1.5µA @ 3.3V) deliver timekeeping current consumption lower than or equivalent to the MCP79412T-I/ST (1.2µA @ 3.3V).

Extended Voltage Range: RX-8571LCB0 and RX-8803LC:UB3 support 1.6V ~ 5.5V supply voltage, providing broader operational margins than the MCP79412T-I/ST (1.8V ~ 5.5V).

Memory and Feature Requirements: ISL12022MAIBZ-T provides 128-byte SRAM with Daylight Savings support. PCF2127T/2Y offers 512-byte memory with integrated Watchdog Timer and TCXO/Crystal support.

Moisture Sensitivity: All substitutes except PCF2127T/2Y maintain MSL 1 (Unlimited) rating, matching the MCP79412T-I/ST specification.

Frequently Asked Questions (FAQ)

Q: Can DS1308U-33+T directly replace MCP79412T-I/ST in existing PCB layouts?

A: DS1308U-33+T is available in 8-TSSOP and 8-MSOP packages. The 8-TSSOP variant matches the MCP79412T-I/ST footprint (0.173", 4.40mm width). However, verify pinout compatibility before PCB implementation, as pin assignments may differ between manufacturers.

Q: What is the primary difference between ISL12058IUZ-T and MCP79412T-I/ST?

A: ISL12058IUZ-T operates at reduced voltage range (1.8V ~ 3.6V) compared to MCP79412T-I/ST (1.8V ~ 5.5V) and delivers lower timekeeping current (0.65µA @ 1.8V versus 1.2µA @ 3.3V). Both devices support I2C interface, 12/24-hour time format, and -40°C to 85°C operating temperature.

Q: Are EPSON RTC devices (RX-8571LCB0, RX-8803LC:UB3, RX8900SA:UB3) compatible with MCP79412T-I/ST applications?

A: EPSON devices maintain I2C interface compatibility and -40°C to 85°C operating temperature. RX-8571LCB0 and RX-8803LC:UB3 use 12-TFSOJ packages (0.094", 2.40mm width), requiring PCB redesign. RX8900SA:UB3 uses 14-SOIC package (0.197", 5.00mm width). All three support YY-MM-DD-dd date format and Alarm functionality.

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

A: ISL12058IUZ-T delivers 0.65µA timekeeping current at 1.8V, the lowest among all listed substitutes. RX-8571LCB0 provides 0.55µA ~ 0.6µA at 3V ~ 5V. Both are suitable for extended battery life applications.

Q: Does PCF2127T/2Y require special handling due to MSL 3 rating?

A: PCF2127T/2Y carries MSL 3 (168 Hours) moisture sensitivity, compared to MSL 1 (Unlimited) for MCP79412T-I/ST and other substitutes. This requires controlled storage and handling procedures to prevent moisture absorption during manufacturing. Standard MSL 1 devices do not impose these constraints.

Q: Can DS1340Z-33+ be used in applications requiring 12-hour time format?

A: DS1340Z-33+ supports 24-hour time format only, unlike MCP79412T-I/ST which supports both 12/24-hour formats. Applications requiring 12-hour display capability should select DS1338Z-18+, DS1308U-33+T, ISL12022MAIBZ-T, ISL12058IUZ-T, or PCF2127T/2Y.

Q: What are the memory differences between MCP79412T-I/ST and ISL12022MAIBZ-T?

A: MCP79412T-I/ST provides 64-byte SRAM and 1-kilobyte total memory. ISL12022MAIBZ-T offers 128-byte SRAM, providing double the user-accessible memory. ISL12022MAIBZ-T also includes Daylight Savings Time support, absent in MCP79412T-I/ST.

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