1SMA5944 Zener Diode Equivalent & Substitute Parts

Part Overview

The 1SMA5944 is a surface mount silicon zener diode manufactured by Taiwan Semiconductor Corporation, rated at 62 V nominal zener voltage with 1.5 W maximum power dissipation in a DO-214AC (SMA) package. This component is classified as Active product status and is RoHS3 compliant. Alternative equivalent and substitute parts are necessary to address inventory availability, lead time constraints, or specific application requirements while maintaining electrical and mechanical compatibility within the specified parameter tolerances.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	62	V
Tolerance	±5%	%
Power - Max	1.5	W
Impedance (Max)	100	Ohms
Current - Reverse Leakage @ Vr	500	nA @ 47.1 V
Operating Temperature Range	-55 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	DO-214AC (SMA)	—
RoHS Status	ROHS3 Compliant	—

Substitute Part Grouping Explanation

Substitute parts for the 1SMA5944 are classified into two categories based on electrical parameter alignment:

Category 1: Parametric Equivalents (Same Voltage, Same Power) Parts that maintain identical nominal zener voltage (62 V) and maximum power rating (1.5 W) with matching impedance and leakage characteristics. These parts provide direct functional replacement with no circuit redesign required.

Category 2: Voltage Variants (Different Voltage, Same Power) Parts that maintain the same maximum power rating (1.5 W) but operate at different nominal zener voltages (68 V). These parts are suitable only when the application circuit can accommodate the higher voltage specification.

Category 3: Power-Rated Upgrades (Same Voltage, Higher Power) Parts that maintain the same nominal zener voltage (62 V) but provide increased maximum power dissipation (3 W). These parts are suitable for applications requiring higher power handling capability.

Category 4: Combined Variants (Different Voltage, Higher Power) Parts that combine both voltage variation (68 V) and increased power rating (3 W). These parts require both voltage and power compatibility verification.

Substitution eligibility is determined by: nominal zener voltage (Vz), maximum power rating (P-Max), impedance (Zzt), package type (DO-214AC/SMA), mounting type (Surface Mount), and compliance certifications (RoHS3).

Parameter Comparison

Manufacturer Part Number	Manufacturer	Vz (Nom)	Tolerance	Power - Max	Zzt (Max)	Reverse Leakage @ Vr	Operating Temp	Package	Packaging Type	RoHS Status
1SMA5944	Taiwan Semiconductor Corporation	62 V	±5%	1.5 W	100 Ω	500 nA @ 47.1 V	-55 to 150°C	DO-214AC (SMA)	Tape & Reel (TR)	ROHS3 Compliant
1SMA5944_R1_00001	Panjit International Inc.	62 V	±5%	1.5 W	100 Ω	1 µA @ 47.1 V	-55 to 150°C	DO-214AC (SMA)	Tape & Reel (TR)	ROHS3 Compliant
3SMAJ5944B-TP	Micro Commercial Co	62 V	±5%	3 W	100 Ω	1 µA @ 47.1 V	-55 to 150°C	DO-214AC (SMA)	Tape & Reel (TR)	ROHS3 Compliant
1SMA5945BT3G	onsemi	68 V	±5%	1.5 W	120 Ω	500 nA @ 51.7 V	-65 to 150°C	DO-214AC (SMA)	Cut Tape (CT) & Digi-Reel®	ROHS3 Compliant
3SMAJ5945B-TP	Micro Commercial Co	68 V	±5%	3 W	120 Ω	1 µA @ 51.7 V	-55 to 150°C	DO-214AC (SMA)	Tape & Reel (TR)	ROHS3 Compliant

Engineering Selection Recommendations

Direct Replacement (No Circuit Modification Required)

The 1SMA5944_R1_00001 manufactured by Panjit International Inc. is a parametric equivalent suitable for direct substitution. It maintains identical nominal zener voltage (62 V), maximum power rating (1.5 W), impedance (100 Ω), operating temperature range (-55 to 150°C), and package configuration (DO-214AC/SMA). Both parts are RoHS3 compliant and carry Active product status. The reverse leakage specification differs (1 µA versus 500 nA), which represents improved leakage performance and does not preclude substitution.

Power-Rated Upgrade (Same Voltage)

The 3SMAJ5944B-TP manufactured by Micro Commercial Co maintains the same nominal zener voltage (62 V) and package type (DO-214AC/SMA) while providing doubled maximum power dissipation (3 W versus 1.5 W). This part is suitable for applications requiring enhanced thermal performance or higher power handling. The impedance (100 Ω) and operating temperature range (-55 to 150°C) remain consistent. RoHS3 compliance is maintained.

Voltage Variant (Same Power)

The 1SMA5945BT3G manufactured by onsemi operates at 68 V nominal zener voltage with identical 1.5 W maximum power rating. This part is suitable only when the application circuit design accommodates the 6 V voltage differential. The impedance increases to 120 Ω, and the operating temperature range extends to -65°C minimum. RoHS3 compliance is maintained. Packaging differs (Cut Tape & Digi-Reel® versus Tape & Reel).

Combined Variant (Voltage and Power)

The 3SMAJ5945B-TP manufactured by Micro Commercial Co combines 68 V nominal zener voltage with 3 W maximum power rating. This part requires verification that both the higher voltage specification and increased power capability are compatible with the application circuit. Impedance is 120 Ω, and operating temperature range is -55 to 150°C. RoHS3 compliance is maintained.

All substitute parts maintain RoHS3 compliance, Active product status, and surface mount DO-214AC (SMA) package configuration, ensuring mechanical and regulatory compatibility with the original 1SMA5944 specification.

Frequently Asked Questions (FAQ)

Q: Can the 1SMA5944_R1_00001 be used as a direct replacement for the 1SMA5944?

A: Yes. The 1SMA5944_R1_00001 is a parametric equivalent with identical nominal zener voltage (62 V), maximum power rating (1.5 W), impedance (100 Ω), and operating temperature range (-55 to 150°C). Both parts use the DO-214AC (SMA) package and are RoHS3 compliant. No circuit modification is required.

Q: What is the difference between the 1SMA5944 and the 3SMAJ5944B-TP?

A: The primary difference is maximum power dissipation. The 3SMAJ5944B-TP is rated at 3 W compared to 1.5 W for the 1SMA5944. Both maintain 62 V nominal zener voltage, 100 Ω impedance, and -55 to 150°C operating temperature. The 3SMAJ5944B-TP is suitable for applications requiring higher power handling.

Q: Can I substitute the 1SMA5945BT3G for the 1SMA5944?

A: Substitution is possible only if the application circuit is designed to accommodate 68 V nominal zener voltage instead of 62 V. The 1SMA5945BT3G maintains the same 1.5 W power rating but operates at a 6 V higher voltage. Impedance increases to 120 Ω. Verify circuit voltage tolerance before substitution.

Q: Are all substitute parts available in the same packaging format?

A: All substitute parts use the DO-214AC (SMA) surface mount package. However, packaging type (tape format) differs: the 1SMA5944 and most substitutes are supplied in Tape & Reel (TR) format, while the 1SMA5945BT3G is supplied in Cut Tape (CT) & Digi-Reel® format. Verify packaging compatibility with assembly equipment.

Q: Do all substitute parts meet RoHS3 compliance?

A: Yes. All listed substitute parts are RoHS3 compliant, matching the compliance status of the original 1SMA5944. All parts are also REACH unaffected and carry EAR99 ECCN classification.

Q: What is the operating temperature range difference between the 1SMA5944 and 1SMA5945BT3G?

A: The 1SMA5944 operates from -55°C to 150°C, while the 1SMA5945BT3G operates from -65°C to 150°C. The onsemi part provides 10°C lower minimum temperature capability. This difference is relevant only for applications requiring operation below -55°C.

Q: Can I use the 3SMAJ5945B-TP as a substitute?

A: The 3SMAJ5945B-TP can be used only if the application circuit accommodates both 68 V nominal zener voltage and 3 W power rating. This part combines voltage variation and power upgrade, requiring verification of both parameters for circuit compatibility.

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