PT7C4337BLEX Real Time Clock IC Equivalent & Substitute Parts

Part Overview

The PT7C4337BLEX is a Real Time Clock (RTC) IC manufactured by Diodes Incorporated, designed for clock/calendar applications with I2C/2-Wire Serial interface. This 8-TSSOP surface mount device operates across a wide supply voltage range of 1.8V to 5.5V and includes features such as alarm functionality, leap year support, and square wave output. The product is currently classified as obsolete, making equivalent and substitute parts necessary for ongoing design support, production continuity, and system maintenance.

Key Parameters

Parameter	PT7C4337BLEX
Manufacturer	Diodes Incorporated
Product Status	Obsolete
Type	Clock/Calendar
Interface	I2C, 2-Wire Serial
Package / Case	8-TSSOP (0.173", 4.40mm Width)
Voltage - Supply	1.8V ~ 5.5V
Voltage - Supply, Battery	Not specified
Current - Timekeeping (Max)	0.8µA @ 1.2V ~ 1.8V
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
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the PT7C4337BLEX 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.

Supply Voltage Range: The original part operates from 1.8V to 5.5V. Substitute parts must support the minimum voltage requirement of the application. Parts with narrower voltage ranges (e.g., 3.0V minimum) are acceptable only if the application operates within that range.

Package Type: The 8-TSSOP package is the primary form factor. Substitutes in alternative packages (8-SOIC, 10-SMD Module, 16-SOIC, 8-MSOP) are listed as functional equivalents but require PCB layout modification.

Functional Features: Core features (Alarm, Leap Year, Square Wave Output) are present across all substitutes. Additional features (EEPROM, SRAM, Trickle-Charger, Watchdog Timer) do not disqualify a part but represent enhanced capability.

Operating Temperature: All substitutes maintain the -40°C to 85°C operating range.

Compliance: All substitutes are ROHS3 compliant and REACH unaffected, matching the original part's regulatory status.

Parameter Comparison

Parameter	PT7C4337BLEX	1339-31DCGI8	AB-RTCMC-32.768KHZ-B5GA-S3-T	AB-RTCMC-32.768KHZ-EOZ9-S3-DBT	DS1338Z-33+T&R	DS1339AU+	DS1340U-3+	DS1340Z-33+	DS1388Z-33+	DS3232SN#T&R
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
Voltage - Supply (Min)	1.8V	3.3V	1.2V	1.4V	3.0V	1.71V	2.7V	2.97V	2.97V	2.3V
Voltage - Supply (Max)	5.5V	5.5V	5.5V	5.5V	5.5V	5.5V	5.5V	5.5V	3.63V	5.5V
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
Time Format	HH:MM:SS (12/24 hr)	HH:MM:SS (12/24 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 (24 hr)	HH:MM:SS (24 hr)	HH:MM:SS:hh (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	YY-MM-DD-dd	YY-MM-DD-dd	YY-MM-DD-dd	YY-MM-DD-dd	YY-MM-DD-dd
Package / Case	8-TSSOP (0.173", 4.40mm)	8-SOIC (0.154", 3.90mm)	10-SMD Module	10-SMD Module	8-SOIC (0.154", 3.90mm)	8-TSSOP, 8-MSOP (0.118", 3.00mm)	8-TSSOP, 8-MSOP (0.118", 3.00mm)	8-SOIC (0.154", 3.90mm)	8-SOIC (0.154", 3.90mm)	20-SOIC (0.295", 7.50mm)
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Direct Package Replacement (8-TSSOP Form Factor):

DS1339AU+ and DS1340U-3+ are available in 8-TSSOP/8-MSOP packages, providing the closest physical footprint match to the PT7C4337BLEX. Both are active products with full compliance certifications. DS1339AU+ supports supply voltage down to 1.71V and includes trickle-charger functionality. DS1340U-3+ operates from 2.7V minimum and includes leap year and trickle-charger features.

Functional Equivalents with Package Modification:

For applications where PCB layout modification is acceptable, the following active products provide enhanced functionality:

AB-RTCMC-32.768KHZ-B5GA-S3-T (10-SMD Module) offers the lowest supply voltage minimum (1.2V) and lowest timekeeping current (0.45µA ~ 0.55µA), making it suitable for ultra-low-power applications.

AB-RTCMC-32.768KHZ-EOZ9-S3-DBT (10-SMD Module) includes 8B EEPROM, SRAM, and trickle-charger, providing extended functionality for applications requiring non-volatile storage.

DS1338Z-33+T&R (8-SOIC) includes 56B NVSRAM and is available in high inventory (12,974 pcs), supporting applications requiring non-volatile memory.

DS3232SN#T&R (20-SOIC) provides 236B memory with integrated SRAM and TCXO/Crystal, suitable for precision timing applications requiring extended storage capacity.

Voltage Range Considerations:

Applications operating at supply voltages below 2.3V should prioritize AB-RTCMC-32.768KHZ-B5GA-S3-T (1.2V minimum) or AB-RTCMC-32.768KHZ-EOZ9-S3-DBT (1.4V minimum). Applications operating at 3.3V or higher have full compatibility across all listed substitutes.

All substitute parts maintain ROHS3 compliance and REACH unaffected status, ensuring regulatory continuity.

Frequently Asked Questions (FAQ)

Q: Can I use a substitute part with a different package type on my existing PCB?

A: Direct substitution without PCB modification requires matching package types. The PT7C4337BLEX uses 8-TSSOP (0.173", 4.40mm Width). DS1339AU+ and DS1340U-3+ are available in 8-TSSOP/8-MSOP packages and are pin-compatible alternatives. Other packages (8-SOIC, 10-SMD Module, 16-SOIC, 20-SOIC) require PCB layout redesign.

Q: What is the minimum supply voltage I should consider for a substitute?

A: The PT7C4337BLEX operates from 1.8V minimum. If your application requires this low voltage operation, select AB-RTCMC-32.768KHZ-B5GA-S3-T (1.2V minimum) or AB-RTCMC-32.768KHZ-EOZ9-S3-DBT (1.4V minimum). For applications operating at 2.7V or higher, all listed substitutes are compatible.

Q: Are all substitute parts currently in production?

A: Yes. All listed substitute parts have Active product status. The PT7C4337BLEX is Obsolete, making these active alternatives necessary for production continuity and long-term availability.

Q: Do substitute parts support the same I2C communication protocol?

A: Yes. All substitute parts use I2C/2-Wire Serial interface, maintaining firmware and software compatibility with the original PT7C4337BLEX design.

Q: Which substitute offers the lowest power consumption during timekeeping?

A: AB-RTCMC-32.768KHZ-B5GA-S3-T provides the lowest timekeeping current at 0.45µA ~ 0.55µA @ 2V ~ 5V, compared to the PT7C4337BLEX at 0.8µA @ 1.2V ~ 1.8V.

Q: Can I use a substitute with additional features like EEPROM or SRAM?

A: Yes. Parts with additional memory (DS1338Z-33+T&R with 56B NVSRAM, DS1388Z-33+ with 512B EEPROM, DS3232SN#T&R with 236B memory) are functional substitutes. Additional features do not prevent compatibility; however, firmware must be updated to utilize these features if required by the application.

Q: What is the inventory status of these substitute parts?

A: All substitute parts are available in significant quantities: 1339-31DCGI8 (2,100 pcs), AB-RTCMC-32.768KHZ-B5GA-S3-T (2,787 pcs), AB-RTCMC-32.768KHZ-EOZ9-S3-DBT (2,624 pcs), DS1338Z-33+T&R (12,974 pcs), DS1339AU+ (2,828 pcs), DS1340U-3+ (3,620 pcs), DS1340Z-33+ (2,838 pcs), DS1388Z-33+ (3,420 pcs), DS3232SN#T&R (10,400 pcs).

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed are ROHS3 compliant and REACH unaffected, matching the regulatory compliance of the PT7C4337BLEX.

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