PT7C43390WE Real Time Clock (RTC) IC Equivalent & Substitute Parts

Part Overview

The PT7C43390WE is a Real Time Clock (RTC) IC manufactured by Diodes Incorporated, designed for Clock/Calendar applications with I2C 2-Wire Serial interface in an 8-SOIC (0.154", 3.90mm Width) surface mount package. This device is classified as Obsolete, making substitute parts necessary for new designs and ongoing production requirements. The PT7C43390WE provides timekeeping functionality with alarm capability, leap year support, and square wave output, operating across a wide supply voltage range of 1.35V to 5.5V with minimal timekeeping current consumption of 0.6µA to 0.7µA at 3V to 5V.

Key Parameters

Parameter	PT7C43390WE
Manufacturer	Diodes Incorporated
Product Status	Obsolete
Type	Clock/Calendar
Interface	I2C, 2-Wire Serial
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Voltage - Supply	1.35V ~ 5.5V
Current - Timekeeping (Max)	0.6µA ~ 0.7µA @ 3V ~ 5V
Operating Temperature	-40°C ~ 85°C
Time Format	HH:MM:SS (12/24 hr)
Date Format	YY-MM-DD-dd
Features	Alarm, Leap Year, Square Wave Output
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitute parts for the PT7C43390WE are selected based on the following critical parameters that determine functional compatibility:

Primary Substitution Criteria:

Interface: I2C, 2-Wire Serial (mandatory match)
Type: Clock/Calendar RTC IC
Operating Temperature: -40°C ~ 85°C (required range)
Time Format: HH:MM:SS with 12/24 hour capability
Date Format: YY-MM-DD-dd
Features: Alarm and Leap Year support (core functionality)
RoHS Status: ROHS3 Compliant
Moisture Sensitivity Level: 1 (Unlimited)

Secondary Compatibility Parameters:

Supply Voltage Range: Minimum 1.35V to 5.5V overlap required
Timekeeping Current: Low power operation (typically under 1mA)
Mounting Type: Surface Mount preferred for modern PCB designs
Package options: 8-SOIC, 8-WCDFN, 8-TSSOP/8-MSOP, or 8-UMAX acceptable

Substitute parts are grouped into two categories: direct package replacements (8-SOIC) and functionally equivalent alternatives with different surface mount packages. All substitutes maintain I2C interface compatibility, support 12/24 hour time format, include alarm and leap year functionality, and operate within the -40°C to 85°C temperature range.

Parameter Comparison

Parameter	PT7C43390WE	AB-RTCMC-32.768KHZ-AIGZ-S7-T	BQ32000DR	DS1307N+	DS1308U-33+	DS1338U-33+T&R	DS1339U-33+	DS1342U+	DS3231SN#T&R	ISL12008IB8Z	ISL12008IB8Z-T
Manufacturer	Diodes Inc.	Abracon LLC	Texas Instruments	Analog Devices/Maxim	Analog Devices/Maxim	Analog Devices/Maxim	Analog Devices/Maxim	Analog Devices/Maxim	Analog Devices/Maxim	Renesas Electronics	Renesas Electronics
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active	Active	Active	Active
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, 2-Wire Serial
Package / Case	8-SOIC (0.154", 3.90mm)	8-WCDFN	8-SOIC (0.154", 3.90mm)	8-DIP (0.300", 7.62mm)	8-TSSOP, 8-MSOP (0.118", 3.00mm)	8-TSSOP, 8-MSOP (0.118", 3.00mm)	8-TSSOP, 8-MSOP (0.118", 3.00mm)	8-TSSOP, 8-MSOP (0.118", 3.00mm)	16-SOIC (0.295", 7.50mm)	8-SOIC (0.154", 3.90mm)	8-SOIC (0.154", 3.90mm)
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Through Hole	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Voltage - Supply	1.35V ~ 5.5V	1V ~ 4.4V	3V ~ 3.6V	4.5V ~ 5.5V	3V ~ 5.5V	3V ~ 5.5V	2.97V ~ 5.5V	1.8V ~ 5.5V	2.3V ~ 5.5V	2.7V ~ 5.5V	2.7V ~ 5.5V
Current - Timekeeping (Max)	0.6µA ~ 0.7µA @ 3V ~ 5V	0.4µA ~ 0.95µA @ 1V ~ 4.4V	100µA @ 3.3V	200µA @ 5V	125µA ~ 200µA @ 3V ~ 5.5V	125µA ~ 200µA @ 3.63V ~ 5.5V	200µA @ 5.5V	0.6µA ~ 0.7µA @ 3V ~ 5V	110µA ~ 170µA @ 3.63V ~ 5.5V	4µA ~ 6µA @ 3V ~ 5V	4µA ~ 6µA @ 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
Time Format	HH:MM:SS (12/24 hr)	HH:MM:SS:hh (24 hr)	HH:MM:SS (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)	HH:MM:SS (12/24 hr)	HH:MM:SS (12/24 hr)	HH:MM:SS:hh (24 hr)	HH:MM:SS:hh (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-dd	YY-MM-DD-dd
Features	Alarm, Leap Year, Square Wave Output	Alarm, Leap Year, Watchdog Timer	Leap Year, Square Wave Output, Trickle-Charger	Leap Year, NVSRAM, Square Wave Output	Leap Year, NVSRAM, Square Wave Output	Leap Year, NVSRAM, Square Wave Output	Alarm, Leap Year, Square Wave Output, Trickle-Charger	Alarm, Leap Year, Square Wave Output	Alarm, Leap Year, Square Wave Output, TCXO/Crystal	Alarm, Leap Year	Alarm, Leap Year
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

All substitute parts listed are Active status components from established manufacturers (Abracon LLC, Texas Instruments, Analog Devices Inc./Maxim Integrated, and Renesas Electronics Corporation), ensuring long-term availability and supply chain stability compared to the Obsolete PT7C43390WE. All substitutes maintain ROHS3 compliance and MSL 1 (Unlimited) ratings, meeting environmental and moisture handling requirements equivalent to the original part.

Direct Package Replacement (8-SOIC): ISL12008IB8Z and ISL12008IB8Z-T from Renesas Electronics provide the closest form-factor match in 8-SOIC (0.154", 3.90mm Width) surface mount package. These parts support I2C interface, include alarm and leap year functionality, and operate across -40°C to 85°C. The ISL12008 series offers lower timekeeping current (4µA to 6µA) compared to the PT7C43390WE, with supply voltage range of 2.7V to 5.5V. ISL12008IB8Z-T is packaged in Cut Tape & Digi-Reel format for production environments.

Alternative Surface Mount Options: DS1342U+ from Analog Devices/Maxim Integrated matches the PT7C43390WE's timekeeping current specification (0.6µA to 0.7µA @ 3V to 5V) and includes alarm, leap year, and square wave output features. This part uses 8-TSSOP/8-MSOP (0.118", 3.00mm Width) package with supply voltage range of 1.8V to 5.5V, providing broader low-voltage compatibility.

DS1339U-33+ offers alarm, leap year, square wave output, and trickle-charger functionality in 8-TSSOP/8-MSOP package with supply voltage range of 2.97V to 5.5V and timekeeping current of 200µA @ 5.5V.

AB-RTCMC-32.768KHZ-AIGZ-S7-T from Abracon LLC provides 8-WCDFN package option with watchdog timer feature, supporting supply voltage of 1V to 4.4V and timekeeping current of 0.4µA to 0.95µA.

Through-Hole Alternative: DS1307N+ from Analog Devices/Maxim Integrated offers through-hole 8-DIP (0.300", 7.62mm) package for legacy board designs, with 56B NVSRAM, leap year, and square wave output support.

Higher Pin-Count Option: DS3231SN#T&R provides 16-SOIC package with integrated temperature-compensated crystal oscillator (TCXO), alarm, leap year, and square wave output features, suitable for applications requiring enhanced frequency stability.

Frequently Asked Questions (FAQ)

Q: Can I directly replace PT7C43390WE with ISL12008IB8Z without PCB modifications? A: Yes. Both parts use identical 8-SOIC (0.154", 3.90mm Width) surface mount package with the same pin pitch and footprint. I2C interface compatibility and functional feature overlap (alarm, leap year, square wave output) enable direct substitution. Verify supply voltage requirements and timekeeping current specifications for your application.

Q: What is the key difference between ISL12008IB8Z and ISL12008IB8Z-T? A: Both parts are functionally identical with the same electrical specifications. The primary difference is packaging format: ISL12008IB8Z is supplied in Tube packaging, while ISL12008IB8Z-T is supplied in Cut Tape & Digi-Reel format optimized for automated production environments.

Q: Why do some substitutes have different timekeeping current specifications? A: Timekeeping current varies based on silicon design, manufacturing process, and operating voltage. Lower timekeeping current (0.4µA to 0.7µA) indicates more efficient power consumption during battery-backed operation. Higher current devices (100µA to 200µA) may offer additional features or different architectural approaches. Select based on your application's power budget requirements.

Q: Is the DS1307N+ suitable for new designs if I need through-hole mounting? A: DS1307N+ is Active status and ROHS3 compliant, making it suitable for new designs requiring through-hole mounting. However, surface mount alternatives (DS1342U+, DS1339U-33+, ISL12008IB8Z) are preferred for modern PCB designs due to smaller footprint and automated assembly compatibility.

Q: What does the 12/24 hour time format difference mean for substitution? A: PT7C43390WE, DS1307N+, DS1308U-33+, DS1338U-33+T&R, DS1339U-33+, and DS1342U+ support both 12-hour and 24-hour time formats via software configuration. AB-RTCMC-32.768KHZ-AIGZ-S7-T and ISL12008 series support 24-hour format only. This is a software-selectable feature in most devices and does not prevent substitution; verify your firmware supports the target device's capabilities.

Q: Can I use DS3231SN#T&R as a drop-in replacement for PT7C43390WE? A: DS3231SN#T&R is functionally compatible but requires PCB layout changes due to different package (16-SOIC vs. 8-SOIC) and pin count. This part is suitable for new designs where enhanced frequency stability from integrated TCXO is beneficial, but not for direct board-level replacement without redesign.

Q: Are all substitute parts available in equivalent inventory quantities? A: Inventory availability varies by supplier and part number. ISL12008IB8Z-T (1,350 pcs), DS1342U+ (2,100 pcs), and DS1339U-33+ (1,774 pcs) have lower stock levels compared to BQ32000DR (25,100 pcs) and AB-RTCMC-32.768KHZ-AIGZ-S7-T (84,205 pcs). Verify current inventory status with your component supplier for production planning.

Q: What supply voltage range should I prioritize when selecting a substitute? A: PT7C43390WE operates from 1.35V to 5.5V. For maximum compatibility with existing designs, prioritize substitutes with overlapping or broader supply voltage ranges: DS1342U+ (1.8V to 5.5V), AB-RTCMC-32.768KHZ-AIGZ-S7-T (1V to 4.4V), and ISL12008 series (2.7V to 5.5V) provide excellent voltage range coverage. Verify your application's actual supply voltage requirements before final selection.

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