Equivalent & Substitute Parts for X1226V8Z

Part Overview

The X1226V8Z is a Real Time Clock (RTC) IC with Clock/Calendar functionality manufactured by Renesas Electronics Corporation. This device integrates I2C/2-Wire Serial interface capability in an 8-TSSOP surface mount package. The X1226V8Z is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. Substitute parts must maintain functional compatibility across core timing, interface, and electrical parameters while accommodating package and feature variations.

Key Parameters

Parameter	X1226V8Z Specification
Manufacturer	Renesas Electronics Corporation
Category	Clock/Timing - RTC Clock/Calendar
Interface	I2C, 2-Wire Serial
Package Type	8-TSSOP (0.173", 4.40mm Width)
Time Format	HH:MM:SS (12/24 hr)
Date Format	YY-MM-DD-dd
Supply Voltage	2.7V ~ 5.5V
Battery Voltage	1.8V ~ 5.5V
Timekeeping Current (Max)	10µA ~ 20µA @ 2.7V ~ 5V
Operating Temperature	0°C ~ 70°C
Features	Alarm, Leap Year
Product Status	Obsolete
RoHS Status	ROHS3 Compliant
MSL Rating	1 (Unlimited)

Substitute Part Grouping Explanation

Substitute parts are grouped based on strict parameter compatibility across the following criteria:

Primary Compatibility Parameters:

Interface: I2C, 2-Wire Serial (mandatory match)
Time Format: HH:MM:SS with 12/24 hour support (mandatory match)
Date Format: YY-MM-DD-dd (mandatory match)
Supply Voltage Range: Minimum 2.7V support required
Battery Voltage Range: Minimum 1.8V support required
Features: Alarm and Leap Year support (mandatory match)
RoHS3 Compliance (mandatory match)
MSL Rating: 1 (Unlimited) preferred for compatibility

Secondary Compatibility Parameters:

Package Type: 8-TSSOP preferred; 8-SOIC and 8-TSSOP/8-MSOP acceptable with PCB layout adjustment
Timekeeping Current: Lower values preferred for power efficiency
Operating Temperature: Extended range (-40°C ~ 85°C) provides broader application support
Product Status: Active status ensures ongoing availability

Substitutes are divided into two groups: Direct Package Match (8-TSSOP) and Package Variant (8-SOIC, 8-TSSOP/8-MSOP) requiring layout consideration.

Parameter Comparison

Direct Package Match Group (8-TSSOP)

Parameter	X1226V8Z	ISL12026IVZ-T	DS1339AU+T	DS1339BU+T	DS1341U+
Manufacturer	Renesas	Renesas	Analog Devices/Maxim	Analog Devices/Maxim	Analog Devices/Maxim
Package	8-TSSOP	8-TSSOP	8-TSSOP/8-MSOP	8-TSSOP/8-MSOP	8-TSSOP/8-MSOP
Interface	I2C, 2-Wire	I2C, 2-Wire	I2C, 2-Wire	I2C, 2-Wire	I2C, 2-Wire
Time Format	HH:MM:SS (12/24 hr)	HH:MM:SS (12/24 hr)	HH:MM:SS (12/24 hr)	HH:MM:SS (12/24 hr)	HH:MM:SS (12/24 hr)
Date Format	YY-MM-DD-dd	YY-MM-DD-dd	YY-MM-DD-dd	YY-MM-DD-dd	YY-MM-DD-dd
Supply Voltage	2.7V ~ 5.5V	2.7V ~ 5.5V	1.71V ~ 5.5V	1.71V ~ 5.5V	1.8V ~ 5.5V
Battery Voltage	1.8V ~ 5.5V	1.8V ~ 5.5V	1.3V ~ 3.7V	1.3V ~ 3.7V	N/A
Timekeeping Current (Max)	10µA ~ 20µA @ 2.7V ~ 5V	10µA ~ 20µA @ 2.7V ~ 5.5V	200µA @ 1.71V ~ 5.5V	200µA @ 1.71V ~ 5.5V	0.5µA ~ 0.6µA @ 3V ~ 5V
Operating Temperature	0°C ~ 70°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Features	Alarm, Leap Year	Alarm, Leap Year	Alarm, Leap Year, Square Wave Output, Trickle-Charger	Alarm, Leap Year, Square Wave Output, Trickle-Charger	Alarm, Leap Year, Square Wave Output
Product Status	Obsolete	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
MSL Rating	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Package Variant Group (8-SOIC)

Parameter	X1226V8Z	DS1307ZN+	DS1307ZN+T&R	DS1338Z-18+
Manufacturer	Renesas	Analog Devices/Maxim	Analog Devices/Maxim	Analog Devices/Maxim
Package	8-TSSOP	8-SOIC	8-SOIC	8-SOIC
Interface	I2C, 2-Wire	I2C, 2-Wire	I2C, 2-Wire	I2C, 2-Wire
Time Format	HH:MM:SS (12/24 hr)	HH:MM:SS (12/24 hr)	HH:MM:SS (12/24 hr)	HH:MM:SS (12/24 hr)
Date Format	YY-MM-DD-dd	YY-MM-DD-dd	YY-MM-DD-dd	YY-MM-DD-dd
Supply Voltage	2.7V ~ 5.5V	4.5V ~ 5.5V	4.5V ~ 5.5V	1.71V ~ 5.5V
Battery Voltage	1.8V ~ 5.5V	2V ~ 4.6V	2V ~ 4.6V	1.3V ~ 3.7V
Timekeeping Current (Max)	10µA ~ 20µA @ 2.7V ~ 5V	200µA @ 5V	200µA @ 5V	100µA @ 1.89V
Operating Temperature	0°C ~ 70°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Features	Alarm, Leap Year	Leap Year, NVSRAM, Square Wave Output	Leap Year, NVSRAM, Square Wave Output	Leap Year, NVSRAM, Square Wave Output
Product Status	Obsolete	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
MSL Rating	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Extended Package Variant Group (28-SOP, 18-SOX)

Parameter	X1226V8Z	M41T11MH6F	M41T81SMY6F	MCP79402T-I/MNY
Manufacturer	Renesas	STMicroelectronics	STMicroelectronics	Microchip Technology
Package	8-TSSOP	28-SOP	18-SOX	8-WFDFN
Interface	I2C, 2-Wire	I2C, 2-Wire	I2C, 2-Wire	I2C, 2-Wire
Time Format	HH:MM:SS (12/24 hr)	HH:MM:SS	HH:MM:SS:hh (24 hr)	HH:MM:SS (12/24 hr)
Date Format	YY-MM-DD-dd	YY-MM-DD-dd	YY-MM-DD-dd	YY-MM-DD-dd
Supply Voltage	2.7V ~ 5.5V	2V ~ 5.5V	2.7V ~ 5.5V	1.8V ~ 5.5V
Battery Voltage	1.8V ~ 5.5V	2.5V ~ 4.6V	2V ~ 4.6V	1.3V ~ 5.5V
Timekeeping Current (Max)	10µA ~ 20µA @ 2.7V ~ 5V	70µA @ 2V ~ 5.5V	100µA @ 2.7V ~ 5.5V	1.2µA (Typ) @ 3.3V
Operating Temperature	0°C ~ 70°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Features	Alarm, Leap Year	Leap Year, NVSRAM	Alarm, Leap Year, Square Wave Output, Watchdog Timer	Alarm, Leap Year, Square Wave Output, SRAM, Unique ID
Memory Size	Not specified	56B	Not specified	64B
Product Status	Obsolete	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
MSL Rating	1 (Unlimited)	3 (168 Hours)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

For Direct Replacement (Minimal Design Changes):

ISL12026IVZ-T is the primary substitute for X1226V8Z. Both devices share identical 8-TSSOP packaging, I2C interface, time/date format specifications, and supply voltage ranges. ISL12026IVZ-T is manufactured by Renesas (same OEM as the original part), maintains ROHS3 compliance and MSL-1 rating, and is in active production status. The extended operating temperature range (-40°C ~ 85°C) provides broader application support compared to the original 0°C ~ 70°C specification.

For Extended Temperature Applications:

DS1339AU+T and DS1339BU+T offer identical functional specifications to X1226V8Z with extended operating temperature range (-40°C ~ 85°C). Both are manufactured by Analog Devices/Maxim Integrated, maintain ROHS3 compliance and MSL-1 rating, and are in active production. These devices include additional features (Square Wave Output, Trickle-Charger) not present in the original part. Package compatibility is maintained (8-TSSOP/8-MSOP).

For Ultra-Low Power Applications:

DS1341U+ provides the lowest timekeeping current specification (0.5µA ~ 0.6µA @ 3V ~ 5V) among all substitutes, making it suitable for battery-powered applications requiring extended operational life. This device maintains I2C interface, time/date format compatibility, and ROHS3/MSL-1 compliance. Operating temperature range extends to -40°C ~ 85°C. Note: Battery voltage support is not specified for this device.

For Package Variant Applications (8-SOIC):

DS1338Z-18+ provides the broadest supply voltage range (1.71V ~ 5.5V) and lowest timekeeping current at minimum voltage (100µA @ 1.89V). This device is suitable for low-voltage applications while maintaining I2C interface, time/date format compatibility, and ROHS3/MSL-1 compliance. Package change from 8-TSSOP to 8-SOIC requires PCB layout modification.

For High-Capacity Memory Applications:

MCP79402T-I/MNY offers 64B integrated SRAM with unique ID functionality, providing enhanced data storage capability beyond the original X1226V8Z specification. This device maintains I2C interface, time/date format compatibility, and ROHS3/MSL-1 compliance. Operating temperature range extends to -40°C ~ 85°C. Package change to 8-WFDFN requires PCB layout modification.

Compliance Verification:

All substitute parts maintain ROHS3 compliance and MSL-1 (Unlimited) moisture sensitivity rating, ensuring compatibility with standard manufacturing and storage processes. All devices are in active production status, ensuring long-term availability and supply chain stability.

Frequently Asked Questions (FAQ)

Q: Can ISL12026IVZ-T be used as a direct drop-in replacement for X1226V8Z?

A: Yes. ISL12026IVZ-T shares identical 8-TSSOP packaging, I2C interface, time/date format specifications (HH:MM:SS 12/24 hr, YY-MM-DD-dd), supply voltage range (2.7V ~ 5.5V), battery voltage range (1.8V ~ 5.5V), and timekeeping current specifications (10µA ~ 20µA). Both devices support Alarm and Leap Year features. No PCB layout changes are required. ISL12026IVZ-T is manufactured by Renesas and maintains ROHS3 compliance and MSL-1 rating.

Q: What is the key difference between DS1339AU+T and DS1339BU+T?

A: Both devices are functionally identical with respect to timing, interface, and electrical specifications. The primary difference is packaging format: DS1339AU+T is supplied in Cut Tape (CT) & Digi-Reel format, while DS1339BU+T is supplied in Tape & Reel (TR) format. Selection depends on procurement and assembly process requirements. Both maintain identical electrical compatibility with X1226V8Z.

Q: Why does DS1341U+ show no battery voltage specification?

A: DS1341U+ is designed for applications where battery backup is not required or is managed through external circuitry. The device maintains timekeeping functionality through its primary supply voltage range (1.8V ~ 5.5V). If battery backup is essential for your application, select DS1339AU+T, DS1339BU+T, or ISL12026IVZ-T instead.

Q: Can I use DS1307ZN+ or DS1338Z-18+ as substitutes despite the package change from 8-TSSOP to 8-SOIC?

A: Yes, with PCB layout modification. Both devices maintain I2C interface, time/date format compatibility (HH:MM:SS 12/24 hr, YY-MM-DD-dd), and ROHS3/MSL-1 compliance. DS1307ZN+ requires supply voltage minimum of 4.5V (higher than X1226V8Z's 2.7V minimum), limiting low-voltage applications. DS1338Z-18+ supports lower supply voltage (1.71V minimum) and is preferred for broader voltage range compatibility. Pin-to-pin mapping differs between 8-TSSOP and 8-SOIC packages; verify pinout compatibility before PCB redesign.

Q: What is the advantage of MCP79402T-I/MNY over other substitutes?

A: MCP79402T-I/MNY provides 64B integrated SRAM with unique ID functionality, enabling data storage and device identification capabilities not present in X1226V8Z. This device offers the lowest typical timekeeping current (1.2µA @ 3.3V) among all substitutes, making it optimal for ultra-low-power battery-backed applications. Extended operating temperature range (-40°C ~ 85°C) and broad supply voltage support (1.8V ~ 5.5V) provide design flexibility. Package change to 8-WFDFN requires PCB layout modification.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed maintain ROHS3 compliance and MSL-1 (Unlimited) moisture sensitivity rating, ensuring compatibility with standard manufacturing processes and storage requirements.

Q: Which substitute provides the best temperature range coverage?

A: All active substitute parts support -40°C ~ 85°C operating temperature range, which exceeds the original X1226V8Z specification (0°C ~ 70°C). This extended range provides broader application support for industrial and automotive environments. If your application requires only 0°C ~ 70°C operation, all substitutes remain fully compatible.

Q: What should I verify before selecting a substitute part?

A: Verify the following parameters: (1) I2C interface requirement confirmation, (2) Time/date format compatibility (HH:MM:SS 12/24 hr, YY-MM-DD-dd), (3) Supply voltage range requirements (minimum 2.7V recommended for X1226V8Z compatibility), (4) Battery voltage requirements if backup power is needed, (5) Package type compatibility with existing PCB layout (8-TSSOP preferred for direct replacement), (6) Feature requirements (Alarm, Leap Year are mandatory; additional features like Square Wave Output or SRAM are optional), (7) Operating temperature range requirements, (8) Timekeeping current specifications for power budget calculations.

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