PT7C43390LE Real Time Clock IC - Equivalent & Substitute Parts

Part Overview

The PT7C43390LE is a Real Time Clock (RTC) IC with Clock/Calendar functionality manufactured by Diodes Incorporated. This device operates as a 2-Wire Serial I2C interface component in an 8-MSOP surface mount package. The part is currently listed as obsolete, making equivalent and substitute parts necessary for ongoing design support, production continuity, and new project implementations.

Key Parameters

Parameter	PT7C43390LE
Manufacturer	Diodes Incorporated
Product Status	Obsolete
Package / Case	8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
Interface	I2C, 2-Wire Serial
Time Format	HH:MM:SS (12/24 hr)
Date Format	YY-MM-DD-dd
Voltage - Supply	1.3V ~ 5.5V
Current - Timekeeping (Max)	0.65µA ~ 0.7µA @ 3V ~ 5V
Operating Temperature	-40°C ~ 85°C
Features	Alarm, Leap Year, Square Wave Output
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the PT7C43390LE is determined by the following critical parameters:

Primary Substitution Criteria:

Interface: I2C, 2-Wire Serial (mandatory match)
Time Format: HH:MM:SS (12/24 hr) (mandatory match)
Date Format: YY-MM-DD-dd (mandatory match)
Operating Temperature: -40°C ~ 85°C (mandatory match)
Mounting Type: Surface Mount (mandatory match)
RoHS Status: ROHS3 Compliant (mandatory match)

Secondary Compatibility Factors:

Voltage Supply Range: 1.3V ~ 5.5V (acceptable if substitute range encompasses or overlaps)
Package / Case: 8-MSOP or equivalent 8-pin surface mount packages
Current Timekeeping: Lower or equal values preferred for power efficiency
Features: Alarm, Leap Year, Square Wave Output (preferred but not mandatory)

Substitutes are grouped into two categories: direct equivalents (same manufacturer, active product status) and manufacturer-recommended alternatives (different manufacturers, active status, enhanced features).

Parameter Comparison

Part Number	Manufacturer	Product Status	Package	Interface	Voltage Supply	Current - Timekeeping (Max)	Operating Temp	Features	RoHS Status
PT7C43390LE	Diodes Incorporated	Obsolete	8-MSOP (0.118", 3.00mm)	I2C, 2-Wire Serial	1.3V ~ 5.5V	0.65µA ~ 0.7µA @ 3V ~ 5V	-40°C ~ 85°C	Alarm, Leap Year, Square Wave Output	ROHS3 Compliant
PT7C43390LEX	Diodes Incorporated	Active	8-MSOP (0.118", 3.00mm)	I2C, 2-Wire Serial	1.3V ~ 5.5V	0.65µA ~ 0.7µA @ 3V ~ 5V	-40°C ~ 85°C	Alarm, Leap Year, Square Wave Output	ROHS3 Compliant
1338-31DVGI	Renesas Electronics Corporation	Active	8-MSOP (0.118", 3.00mm)	I2C, 2-Wire Serial	3.3V ~ 5.5V	5µA @ 3.63V ~ 5.5V	-40°C ~ 85°C	Leap Year, NVSRAM, Square Wave Output	ROHS3 Compliant
AB-RTCMC-32.768KHZ-B5ZE-S3-T	Abracon LLC	Active	10-SMD Module	I2C, 2-Wire Serial	1.2V ~ 5.5V	0.5µA @ 2V ~ 5V	-40°C ~ 85°C	Alarm, Leap Year, Square Wave Output	ROHS3 Compliant
BU9873FVM-GTTR	Rohm Semiconductor	Not For New Designs	8-VSSOP, 8-MSOP (0.110", 2.80mm)	I2C, 2-Wire Serial	1.8V ~ 5.5V	1µA ~ 1.35µA @ 3V ~ 5.5V	-40°C ~ 85°C	Alarm, Leap Year	ROHS3 Compliant
DS1308U-3+T	Analog Devices Inc./Maxim Integrated	Active	8-MSOP (0.118", 3.00mm)	I2C, 2-Wire Serial	2.7V ~ 5.5V	Not specified	-40°C ~ 85°C	Leap Year, NVSRAM, Square Wave Output	ROHS3 Compliant
DS1337S+T&R	Analog Devices Inc./Maxim Integrated	Active	8-SOIC (0.154", 3.90mm)	I2C, 2-Wire Serial	1.8V ~ 5.5V	0.6µA @ 1.3V ~ 1.8V	-40°C ~ 85°C	Alarm, Leap Year, Square Wave Output	ROHS3 Compliant
DS1338C-18#	Analog Devices Inc./Maxim Integrated	Active	16-SOIC (0.295", 7.50mm)	I2C, 2-Wire Serial	1.71V ~ 5.5V	100µA @ 1.89V	-40°C ~ 85°C	Leap Year, NVSRAM, Square Wave Output	ROHS3 Compliant
DS1338U-3+T&R	Analog Devices Inc./Maxim Integrated	Active	8-MSOP (0.118", 3.00mm)	I2C, 2-Wire Serial	2.7V ~ 5.5V	200µA @ 3.3V	-40°C ~ 85°C	Leap Year, NVSRAM, Square Wave Output	ROHS3 Compliant
DS1338U-33+	Analog Devices Inc./Maxim Integrated	Active	8-MSOP (0.118", 3.00mm)	I2C, 2-Wire Serial	3V ~ 5.5V	125µA ~ 200µA @ 3.63V ~ 5.5V	-40°C ~ 85°C	Leap Year, NVSRAM, Square Wave Output	ROHS3 Compliant

Engineering Selection Recommendations

Direct Equivalent (Recommended Primary Choice):

PT7C43390LEX is the active production equivalent of PT7C43390LE. Both parts share identical electrical specifications, package dimensions, and feature sets. This part maintains full compatibility with existing designs and offers the advantage of active product status with established supply chain availability.

Alternative Selections Based on Application Requirements:

DS1337S+T&R and DS1308U-3+T&R are active alternatives from Analog Devices Inc./Maxim Integrated with ROHS3 compliance. These parts maintain I2C interface compatibility and operating temperature range alignment. DS1337S+T&R operates in an 8-SOIC package (different footprint) with lower timekeeping current at reduced voltage ranges. DS1308U-3+T&R operates in the same 8-MSOP package with NVSRAM feature addition but requires minimum 2.7V supply voltage.

AB-RTCMC-32.768KHZ-B5ZE-S3-T from Abracon LLC is a module-based alternative with superior timekeeping current efficiency (0.5µA) and extended voltage supply range (1.2V ~ 5.5V). This part requires PCB layout accommodation for a 10-SMD module footprint rather than discrete 8-pin IC.

1338-31DVGI from Renesas Electronics Corporation provides NVSRAM integration with active product status but operates at higher timekeeping current (5µA) and requires minimum 3.3V supply voltage.

BU9873FVM-GTTR from Rohm Semiconductor is marked "Not For New Designs" and should not be selected for new development projects despite meeting core substitution criteria.

Frequently Asked Questions (FAQ)

Q: Can PT7C43390LEX be used as a direct replacement for PT7C43390LE?

A: Yes. PT7C43390LEX is the active production equivalent with identical electrical specifications, package dimensions (8-MSOP, 0.118" × 3.00mm), interface (I2C, 2-Wire Serial), voltage supply range (1.3V ~ 5.5V), timekeeping current (0.65µA ~ 0.7µA @ 3V ~ 5V), and feature set (Alarm, Leap Year, Square Wave Output). The only difference is product status (Active vs. Obsolete) and packaging format (Tape & Reel vs. standard).

Q: What are the key differences between 8-MSOP and 8-SOIC packages?

A: Both are 8-pin surface mount packages but differ in physical dimensions and PCB footprint. The 8-MSOP (0.118" width, 3.00mm) is narrower than 8-SOIC (0.154" width, 3.90mm). Designs using DS1337S+T&R (8-SOIC) require PCB layout modification compared to PT7C43390LE (8-MSOP). Pin-to-pin functionality remains compatible for I2C interface applications.

Q: Which substitute offers the lowest power consumption?

A: AB-RTCMC-32.768KHZ-B5ZE-S3-T from Abracon LLC provides the lowest timekeeping current at 0.5µA @ 2V ~ 5V. This module-based solution also supports the widest voltage supply range (1.2V ~ 5.5V). Trade-off consideration: this part uses a 10-SMD module package rather than discrete 8-pin IC, requiring different PCB footprint design.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts maintain ROHS3 compliance matching the original PT7C43390LE specification.

Q: Why is BU9873FVM-GTTR marked "Not For New Designs"?

A: BU9873FVM-GTTR carries product status "Not For New Designs" from Rohm Semiconductor. This designation indicates the manufacturer does not recommend this part for new development projects. While it meets core substitution criteria, selection should be limited to legacy design maintenance only.

Q: What is the minimum voltage supply requirement across all substitutes?

A: PT7C43390LE and PT7C43390LEX support the lowest minimum voltage at 1.3V. AB-RTCMC-32.768KHZ-B5ZE-S3-T extends this to 1.2V. Other alternatives require higher minimums: DS1337S+T&R (1.8V), BU9873FVM-GTTR (1.8V), DS1308U-3+T (2.7V), DS1338C-18# (1.71V), DS1338U-3+T&R (2.7V), DS1338U-33+ (3V), and 1338-31DVGI (3.3V). Verify application power supply specifications before selection.

Q: Can I use a 16-SOIC package part like DS1338C-18# as a substitute?

A: DS1338C-18# maintains I2C interface, time/date format, operating temperature, and ROHS3 compliance. However, the 16-SOIC package (0.295" × 7.50mm) is significantly larger than the original 8-MSOP (0.118" × 3.00mm). This substitution requires complete PCB layout redesign and is suitable only when additional package real estate and NVSRAM memory are design requirements.

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