ISL12025IBZ Equivalent & Substitute Parts

Part Overview

The ISL12025IBZ is a Real Time Clock (RTC) IC with Clock/Calendar functionality manufactured by Renesas Electronics Corporation. It features I2C/2-Wire Serial interface, alarm capability, leap year support, supervisor function, unique ID, and watchdog timer in an 8-SOIC package. The device operates across 2.7V to 5.5V supply voltage with battery backup from 1.8V to 5.5V, consuming 10µA to 20µA during timekeeping at nominal supply voltage.

The ISL12025IBZ is classified as obsolete. Equivalent and substitute parts are necessary to maintain design continuity and ensure component availability for new production runs and field replacements.

Key Parameters

Parameter	ISL12025IBZ
Manufacturer	Renesas Electronics Corporation
Category	Clock/Timing
Type	Clock/Calendar
Interface	I2C, 2-Wire Serial
Package / Case	8-SOIC (0.154", 3.90mm Width)
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
Mounting Type	Surface Mount
Features	Alarm, Leap Year, Supervisor, Unique ID, Watchdog Timer
RoHS Status	ROHS3 Compliant
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution of the ISL12025IBZ is determined by the following critical parameters:

Interface Compatibility: All substitute parts must support I2C/2-Wire Serial communication to maintain firmware and PCB design compatibility.

Package Compatibility: The 8-SOIC (0.154", 3.90mm Width) package is the primary form factor. Substitutes in alternative packages (8-TSSOP, 8-MSOP, 8-TDFN) require PCB layout modification but maintain electrical compatibility through identical pin assignments and signal definitions.

Voltage Operating Range: Supply voltage range of 2.7V ~ 5.5V and battery backup voltage range of 1.8V ~ 5.5V define the power supply requirements. Substitutes with overlapping or extended voltage ranges are acceptable.

Time and Date Format: HH:MM:SS (12/24 hr) and YY-MM-DD-dd formats are standard across all RTC devices in this category and do not restrict substitution.

Operating Temperature: -40°C ~ 85°C industrial temperature range is maintained across all substitute parts.

Compliance: RoHS3 compliance and REACH unaffected status are required for regulatory alignment.

Parameter Comparison

Part Number	Manufacturer	Package / Case	Voltage - Supply	Voltage - Supply, Battery	Current - Timekeeping (Max)	Operating Temperature	Features	Product Status
ISL12025IBZ	Renesas Electronics	8-SOIC (0.154", 3.90mm)	2.7V ~ 5.5V	1.8V ~ 5.5V	10µA ~ 20µA @ 2.7V ~ 5.5V	-40°C ~ 85°C	Alarm, Leap Year, Supervisor, Unique ID, Watchdog Timer	Obsolete
DS1338U-18+	Analog Devices Inc./Maxim Integrated	8-TSSOP, 8-MSOP (0.118", 3.00mm)	1.71V ~ 5.5V	1.3V ~ 3.7V	100µA @ 1.89V	-40°C ~ 85°C	Leap Year, NVSRAM, Square Wave Output	Active
DS1338U-33+T&R	Analog Devices Inc./Maxim Integrated	8-TSSOP, 8-MSOP (0.118", 3.00mm)	3V ~ 5.5V	1.3V ~ 3.7V	125µA ~ 200µA @ 3.63V ~ 5.5V	-40°C ~ 85°C	Leap Year, NVSRAM, Square Wave Output	Active
DS1339AD+T	Analog Devices Inc./Maxim Integrated	8-TDFN EP	1.71V ~ 5.5V	1.3V ~ 3.7V	200µA @ 1.71V ~ 5.5V	-40°C ~ 85°C	Alarm, Leap Year, Square Wave Output, Trickle-Charger	Active
DS1339BU+	Analog Devices Inc./Maxim Integrated	8-TSSOP, 8-MSOP (0.118", 3.00mm)	1.71V ~ 5.5V	1.3V ~ 3.7V	200µA @ 1.71V ~ 5.5V	-40°C ~ 85°C	Alarm, Leap Year, Square Wave Output, Trickle-Charger	Active
DS1339U-3+T&R	Analog Devices Inc./Maxim Integrated	8-TSSOP, 8-MSOP (0.118", 3.00mm)	2.7V ~ 5.5V	1.3V ~ 3.7V	150µA @ 3.3V	-40°C ~ 85°C	Alarm, Leap Year, Square Wave Output, Trickle-Charger	Active
DS1340Z-18+	Analog Devices Inc./Maxim Integrated	8-SOIC (0.154", 3.90mm)	1.71V ~ 5.5V	1.3V ~ 3.7V	100µA @ 1.89V	-40°C ~ 85°C	Leap Year, Trickle-Charger	Active
DS1340Z-3+T&R	Analog Devices Inc./Maxim Integrated	8-SOIC (0.154", 3.90mm)	2.7V ~ 5.5V	1.3V ~ 3.7V	125µA @ 3.3V	-40°C ~ 85°C	Leap Year, Trickle-Charger	Active
DS1341T+T&R	Analog Devices Inc./Maxim Integrated	8-WDFN Exposed Pad	1.8V ~ 5.5V	Not Specified	0.5µA ~ 0.6µA @ 3V ~ 5V	-40°C ~ 85°C	Alarm, Leap Year, Square Wave Output	Active
DS1341U+T&R	Analog Devices Inc./Maxim Integrated	8-TSSOP, 8-MSOP (0.118", 3.00mm)	1.8V ~ 5.5V	Not Specified	0.5µA ~ 0.6µA @ 3V ~ 5V	-40°C ~ 85°C	Alarm, Leap Year, Square Wave Output	Active
DS1342U+	Analog Devices Inc./Maxim Integrated	8-TSSOP, 8-MSOP (0.118", 3.00mm)	1.8V ~ 5.5V	Not Specified	0.6µA ~ 0.7µA @ 3V ~ 5V	-40°C ~ 85°C	Alarm, Leap Year, Square Wave Output	Active

Engineering Selection Recommendations

Direct Package Replacement (8-SOIC): DS1340Z-18+ and DS1340Z-3+T&R maintain the identical 8-SOIC (0.154", 3.90mm Width) package, eliminating PCB layout modifications. Both devices are Active status products from Analog Devices Inc./Maxim Integrated with RoHS3 compliance. DS1340Z-18+ supports extended supply voltage range (1.71V ~ 5.5V) with lower timekeeping current (100µA @ 1.89V). DS1340Z-3+T&R operates within 2.7V ~ 5.5V supply range with 125µA timekeeping current @ 3.3V.

Alternative Package Options: DS1338U-18+, DS1338U-33+T&R, DS1339AD+T, DS1339BU+, DS1339U-3+T&R, DS1341T+T&R, DS1341U+T&R, and DS1342U+ provide functional equivalence with I2C interface compatibility but require PCB redesign due to different package geometries. All are Active status products with RoHS3 compliance.

Low Power Consideration: DS1341T+T&R and DS1341U+T&R offer significantly reduced timekeeping current (0.5µA ~ 0.6µA @ 3V ~ 5V) compared to the ISL12025IBZ, suitable for battery-dependent applications. These devices operate within 1.8V ~ 5.5V supply range but do not specify battery backup voltage.

Feature Alignment: The ISL12025IBZ includes supervisor, unique ID, and watchdog timer functions. DS1339 series devices (DS1339AD+T, DS1339BU+, DS1339U-3+T&R) provide alarm and trickle-charger features. DS1341 and DS1342 series offer alarm and square wave output with ultra-low timekeeping current. Feature differences require firmware evaluation for application-specific requirements.

Frequently Asked Questions (FAQ)

Q: Can DS1340Z-18+ or DS1340Z-3+T&R directly replace ISL12025IBZ without PCB modification?

A: Yes. Both DS1340Z variants maintain the identical 8-SOIC (0.154", 3.90mm Width) package and I2C interface. Pin assignments and signal definitions are compatible. No PCB layout changes are required. DS1340Z-18+ supports lower supply voltage (1.71V minimum) while DS1340Z-3+T&R operates from 2.7V minimum, matching the ISL12025IBZ supply range.

Q: What is the primary difference between DS1338U and DS1339 series?

A: DS1338U series (DS1338U-18+, DS1338U-33+T&R) provides NVSRAM (Non-Volatile Static RAM) and square wave output without alarm functionality. DS1339 series (DS1339AD+T, DS1339BU+, DS1339U-3+T&R) includes alarm capability and trickle-charger feature. Both maintain I2C interface and -40°C ~ 85°C operating temperature.

Q: Are DS1341 and DS1342 series suitable for battery-powered applications?

A: DS1341T+T&R and DS1341U+T&R offer ultra-low timekeeping current (0.5µA ~ 0.6µA @ 3V ~ 5V), significantly lower than ISL12025IBZ (10µA ~ 20µA). However, battery backup voltage is not specified for these devices. Verify battery backup requirements against application specifications before selection.

Q: What packaging options are available for I2C RTC substitutes?

A: Available packages include 8-SOIC (0.154", 3.90mm Width) for DS1340Z series, 8-TSSOP/8-MSOP (0.118", 3.00mm Width) for DS1338U, DS1339BU+, DS1339U-3+T&R, DS1341U+T&R, and DS1342U+, and 8-TDFN Exposed Pad for DS1339AD+T and DS1341T+T&R. Package selection impacts PCB footprint and thermal characteristics.

Q: Do all substitute parts maintain RoHS3 compliance?

A: Yes. All listed substitute parts are RoHS3 compliant and REACH unaffected, matching the regulatory status of ISL12025IBZ.

Q: What is the significance of supply voltage range differences?

A: ISL12025IBZ operates from 2.7V ~ 5.5V. DS1338U-18+ and DS1339 series extend the lower limit to 1.71V, enabling operation in lower-voltage systems. DS1338U-33+T&R and DS1340Z-3+T&R maintain 2.7V ~ 5.5V range. DS1341 and DS1342 series operate from 1.8V ~ 5.5V. Verify system supply voltage compatibility before selection.

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