ISL12027IBZ Equivalent & Substitute Parts

Part Overview

The ISL12027IBZ is a Real Time Clock (RTC) IC with Clock/Calendar functionality, manufactured by Renesas Electronics Corporation. This device integrates I2C/2-Wire Serial interface with comprehensive timekeeping features including alarm, leap year compensation, supervisor, and watchdog timer capabilities. The ISL12027IBZ is classified as obsolete, necessitating identification of active substitute components that maintain functional and electrical compatibility for new designs and production continuity.

Key Parameters

Parameter	ISL12027IBZ
Manufacturer	Renesas Electronics Corporation
Product Status	Obsolete
Package / Case	8-SOIC (0.154", 3.90mm Width)
Interface	I2C, 2-Wire Serial
Type	Clock/Calendar
Time Format	HH:MM:SS (12/24 hr)
Date Format	YY-MM-DD-dd
Voltage - Supply	2.7V ~ 5.5V
Voltage - Supply, Battery	1.8V ~ 5.5V
Current - Timekeeping (Max)	10µA ~ 20µA @ 2.7V ~ 5.5V
Operating Temperature	-40°C ~ 85°C
Features	Alarm, Leap Year, Supervisor, Watchdog Timer
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the ISL12027IBZ is determined by the following critical parameters:

Primary Compatibility Criteria:

Interface: I2C, 2-Wire Serial (mandatory match)
Type: Clock/Calendar with timekeeping functionality
Operating Temperature Range: -40°C ~ 85°C (minimum requirement)
Time Format: HH:MM:SS with 12/24 hour capability
Date Format: YY-MM-DD-dd
RoHS3 Compliance and MSL rating

Package Compatibility: The ISL12027IBZ uses 8-SOIC (0.154", 3.90mm Width) packaging. Substitutes are grouped into two categories:

Direct Package Match (8-SOIC): DS1340Z-33+, DS3231MZ+
Functional Equivalents (8-TSSOP/8-MSOP): DS1337U+T&R, DS1338U-3+T&R, DS1339AU+, DS1339AU+T, DS1340U-33+, DS1341U+

Voltage Supply Compatibility: All substitute parts operate within or exceed the ISL12027IBZ supply voltage range of 2.7V ~ 5.5V, with battery backup voltage support ranging from 1.3V to 5.5V depending on the specific device.

Feature Alignment: Substitutes maintain core RTC functionality (Alarm, Leap Year) with variations in additional features (Square Wave Output, Trickle-Charger, NVSRAM). The ISL12027IBZ's Supervisor and Watchdog Timer features are not universally replicated across all substitutes; M41ST85WMH6F and M41T83SMY6F provide these capabilities.

Parameter Comparison

Part Number	Manufacturer	Package / Case	Interface	Voltage - Supply	Voltage - Supply, Battery	Current - Timekeeping (Max)	Operating Temperature	Time Format	Features	Product Status	RoHS Status
ISL12027IBZ	Renesas Electronics	8-SOIC (0.154", 3.90mm)	I2C, 2-Wire Serial	2.7V ~ 5.5V	1.8V ~ 5.5V	10µA ~ 20µA @ 2.7V ~ 5.5V	-40°C ~ 85°C	HH:MM:SS (12/24 hr)	Alarm, Leap Year, Supervisor, Watchdog Timer	Obsolete	ROHS3 Compliant
DS1337U+T&R	Analog Devices Inc./Maxim Integrated	8-TSSOP, 8-MSOP (0.118", 3.00mm)	I2C, 2-Wire Serial	1.8V ~ 5.5V	—	0.6µA @ 1.3V ~ 1.8V	-40°C ~ 85°C	HH:MM:SS (12/24 hr)	Alarm, Leap Year, Square Wave Output	Active	ROHS3 Compliant
DS1338U-3+T&R	Analog Devices Inc./Maxim Integrated	8-TSSOP, 8-MSOP (0.118", 3.00mm)	I2C, 2-Wire Serial	2.7V ~ 5.5V	1.3V ~ 3.7V	200µA @ 3.3V	-40°C ~ 85°C	HH:MM:SS (12/24 hr)	Leap Year, NVSRAM, Square Wave Output	Active	ROHS3 Compliant
DS1339AU+	Analog Devices Inc./Maxim Integrated	8-TSSOP, 8-MSOP (0.118", 3.00mm)	I2C, 2-Wire Serial	1.71V ~ 5.5V	1.3V ~ 3.7V	200µA @ 1.71V ~ 5.5V	-40°C ~ 85°C	HH:MM:SS (12/24 hr)	Alarm, Leap Year, Square Wave Output, Trickle-Charger	Active	ROHS3 Compliant
DS1339AU+T	Analog Devices Inc./Maxim Integrated	8-TSSOP, 8-MSOP (0.118", 3.00mm)	I2C, 2-Wire Serial	1.71V ~ 5.5V	1.3V ~ 3.7V	200µA @ 1.71V ~ 5.5V	-40°C ~ 85°C	HH:MM:SS (12/24 hr)	Alarm, Leap Year, Square Wave Output, Trickle-Charger	Active	ROHS3 Compliant
DS1340U-33+	Analog Devices Inc./Maxim Integrated	8-TSSOP, 8-MSOP (0.118", 3.00mm)	I2C, 2-Wire Serial	2.97V ~ 5.5V	1.3V ~ 5.5V	150µA @ 5.5V	-40°C ~ 85°C	HH:MM:SS (24 hr)	Leap Year, Trickle-Charger	Active	ROHS3 Compliant
DS1340Z-33+	Analog Devices Inc./Maxim Integrated	8-SOIC (0.154", 3.90mm)	I2C, 2-Wire Serial	2.97V ~ 5.5V	1.3V ~ 5.5V	150µA @ 5.5V	-40°C ~ 85°C	HH:MM:SS (24 hr)	Leap Year, Trickle-Charger	Active	ROHS3 Compliant
DS1341U+	Analog Devices Inc./Maxim Integrated	8-TSSOP, 8-MSOP (0.118", 3.00mm)	I2C, 2-Wire Serial	1.8V ~ 5.5V	—	0.5µA ~ 0.6µA @ 3V ~ 5V	-40°C ~ 85°C	HH:MM:SS (12/24 hr)	Alarm, Leap Year, Square Wave Output	Active	ROHS3 Compliant
DS3231MZ+	Analog Devices Inc./Maxim Integrated	8-SOIC (0.154", 3.90mm)	I2C, 2-Wire Serial	2.3V ~ 5.5V	2.3V ~ 5.5V	130µA ~ 200µA @ 3.63V ~ 5.5V	-40°C ~ 85°C	HH:MM:SS (12/24 hr)	Alarm, Leap Year, Square Wave Output	Active	ROHS3 Compliant
M41ST85WMH6F	STMicroelectronics	28-SOP (0.350", 8.89mm) with SNAPHAT Sockets	I2C, 2-Wire Serial	2.7V ~ 3.6V	2.5V ~ 4.6V	0.5mA @ 2.7V ~ 3.6V	-40°C ~ 85°C	HH:MM:SS:hh (24 hr)	Alarm, Leap Year, NVSRAM, Square Wave Output, Supervisor, Watchdog Timer	Active	ROHS3 Compliant
M41T83SMY6F	STMicroelectronics	18-SOX, 18-SOIC with Crystal (7.5mm Width)	I2C, 2-Wire Serial	3V ~ 5.5V	2V ~ 5.5V	10µA @ 5.5V	-40°C ~ 85°C	HH:MM:SS:hh (24 hr)	Alarm, Leap Year, Square Wave Output, SRAM, Watchdog Timer	Active	ROHS3 Compliant

Engineering Selection Recommendations

Direct Package Replacement (Recommended for PCB Compatibility):

DS1340Z-33+ and DS3231MZ+ are the primary candidates for direct 8-SOIC package substitution. Both devices are active products with ROHS3 compliance and MSL-1 ratings. DS1340Z-33+ maintains the 24-hour time format and trickle-charger functionality, while DS3231MZ+ provides 12/24-hour format flexibility. Both operate within the ISL12027IBZ temperature range and support I2C interface.

Functional Equivalents with Package Adaptation:

For designs permitting package change to 8-TSSOP/8-MSOP (0.118", 3.00mm Width), DS1339AU+ and DS1339AU+T offer comprehensive feature parity including alarm, leap year, and trickle-charger capabilities. These devices are active products with ROHS3 compliance. DS1341U+ provides ultra-low timekeeping current (0.5µA ~ 0.6µA) for power-constrained applications.

Supervisor and Watchdog Timer Preservation:

M41ST85WMH6F (STMicroelectronics) is the only substitute that replicates the ISL12027IBZ's supervisor and watchdog timer features. This device requires package adaptation to 28-SOP and operates within a narrower supply voltage range (2.7V ~ 3.6V). M41T83SMY6F provides watchdog timer functionality with integrated crystal support, though it requires 18-SOX package accommodation.

Compliance and Availability:

All recommended substitutes maintain ROHS3 compliance and are classified as active products with established supply chains. MSL ratings range from 1 (Unlimited) to 3 (168 Hours), supporting standard manufacturing and storage conditions.

Frequently Asked Questions (FAQ)

Q: Can DS1340Z-33+ directly replace ISL12027IBZ without PCB modification?

A: Yes. DS1340Z-33+ uses the same 8-SOIC (0.154", 3.90mm Width) package as ISL12027IBZ. Both devices support I2C interface, -40°C ~ 85°C operating temperature, and ROHS3 compliance. Pin-level compatibility requires verification against device datasheets, but package footprint is identical.

Q: What is the primary difference between DS1340Z-33+ and DS3231MZ+?

A: Both are 8-SOIC package RTC devices with I2C interface. DS1340Z-33+ supports 24-hour time format only, while DS3231MZ+ supports both 12/24-hour formats. DS3231MZ+ operates at lower minimum supply voltage (2.3V vs. 2.97V) and provides higher timekeeping current consumption (130µA ~ 200µA vs. 150µA). DS1340Z-33+ includes trickle-charger functionality.

Q: Why are DS1339AU+ and DS1339AU+T listed separately if they have identical specifications?

A: DS1339AU+ is supplied in Tube packaging, while DS1339AU+T is supplied in Cut Tape (CT) & Digi-Reel® format. Electrical and functional specifications are identical. Selection depends on procurement and assembly requirements.

Q: Does DS1341U+ provide supervisor and watchdog timer functions like ISL12027IBZ?

A: No. DS1341U+ provides Alarm, Leap Year, and Square Wave Output features but does not include supervisor or watchdog timer functionality. For applications requiring these features, M41ST85WMH6F or M41T83SMY6F are appropriate alternatives.

Q: What is the impact of package change from 8-SOIC to 8-TSSOP/8-MSOP?

A: Package change requires PCB redesign. 8-TSSOP/8-MSOP (0.118", 3.00mm Width) is narrower than 8-SOIC (0.154", 3.90mm Width). Pin pitch and footprint differ, necessitating layout modification. Electrical functionality remains compatible if I2C interface and supply voltage requirements are met.

Q: Are M41ST85WMH6F and M41T83SMY6F suitable for ISL12027IBZ replacement in all applications?

A: M41ST85WMH6F and M41T83SMY6F preserve supervisor and watchdog timer features but require significant package adaptation (28-SOP and 18-SOX respectively). M41ST85WMH6F operates within narrower supply voltage range (2.7V ~ 3.6V) compared to ISL12027IBZ (2.7V ~ 5.5V). Suitability depends on application voltage requirements and PCB layout constraints.

Q: What is the timekeeping current advantage of DS1341U+ over other substitutes?

A: DS1341U+ provides ultra-low timekeeping current of 0.5µA ~ 0.6µA at 3V ~ 5V, compared to ISL12027IBZ's 10µA ~ 20µA. This represents 95% reduction in battery backup power consumption, beneficial for battery-backed RTC applications with extended runtime requirements.

Q: Can I use DS1337U+T&R as a direct replacement for ISL12027IBZ?

A: DS1337U+T&R is functionally compatible via I2C interface and supports identical time/date formats and operating temperature range. However, it lacks battery backup voltage specification and uses 8-TSSOP/8-MSOP package instead of 8-SOIC. PCB redesign is required. DS1337U+T&R is suitable only if battery backup is not required and package change is acceptable.

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