SML4738HE3_A/I Zener Diode Equivalent & Substitute Parts

Part Overview

The SML4738HE3_A/I is an 8.2 V, 1 W Zener diode manufactured by Vishay General Semiconductor - Diodes Division in the DO-214AC (SMA) surface mount package. This component is classified as an active product with automotive-grade qualification (AEC-Q101) and is RoHS3 compliant. The part is available in Tape & Reel packaging with 1061 pieces in current inventory.

Substitute parts are identified when equivalent electrical performance and mechanical compatibility are maintained across the same package type and core electrical specifications. Alternative part numbers may differ in packaging format (Cut Tape versus Tape & Reel), tolerance grade, or inventory availability while preserving functional interchangeability.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	8.2	V
Power - Maximum	1	W
Impedance (Maximum)	4.5	Ohms
Current - Reverse Leakage @ 6V	10	µA
Operating Temperature	150	°C
Package / Case	DO-214AC (SMA)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of Zener diodes is determined by equivalence in the following critical parameters:

Electrical Equivalence Criteria:

Zener voltage (Vz): 8.2 V nominal
Maximum power dissipation: 1 W
Impedance (Zzt): 4.5 Ohms maximum
Reverse leakage current: 10 µA @ 6 V
Operating temperature range: 150°C maximum

Mechanical Equivalence Criteria:

Package type: DO-214AC (SMA) surface mount
Mounting configuration: Surface mount technology

Compliance Criteria:

RoHS3 compliance
Moisture sensitivity level: 1 (Unlimited)

Substitute parts identified in this reference maintain all electrical parameters and package specifications. Variations in tolerance grade (±10% versus ±5%) and packaging format (Tape & Reel versus Cut Tape) do not affect functional interchangeability when the above criteria are met. Automotive-grade qualification (AEC-Q101) is present in the main part and one substitute variant but is not a mandatory substitution criterion for non-automotive applications.

Parameter Comparison

Parameter	SML4738HE3_A/I	SML4738-E3/5A	SML4738A-E3/61	SML4738AHE3_A/H
Voltage - Zener (Nom)	8.2 V	8.2 V	8.2 V	8.2 V
Tolerance	±10%	±10%	±5%	±5%
Power - Max	1 W	1 W	1 W	1 W
Impedance (Max)	4.5 Ohms	4.5 Ohms	4.5 Ohms	4.5 Ohms
Current - Reverse Leakage @ 6V	10 µA	10 µA	10 µA	10 µA
Operating Temperature	150°C	150°C	150°C	150°C
Package / Case	DO-214AC (SMA)	DO-214AC (SMA)	DO-214AC (SMA)	DO-214AC (SMA)
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Packaging Format	Tape & Reel (TR)	Cut Tape (CT)	Cut Tape (CT)	Tape & Reel (TR)
Grade	Automotive	Standard	Standard	Automotive
Qualification	AEC-Q101	None Listed	None Listed	AEC-Q101
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
Inventory (Pcs)	1061	8092	27300	2287

Engineering Selection Recommendations

SML4738-E3/5A (±10% Tolerance, Cut Tape)

This substitute maintains identical electrical specifications and tolerance to the main part. The primary difference is packaging format (Cut Tape versus Tape & Reel). Selection is appropriate for applications where Cut Tape packaging is acceptable and higher inventory availability (8092 pieces) is advantageous. This part does not carry automotive-grade qualification.

SML4738A-E3/61 (±5% Tolerance, Cut Tape)

This substitute offers tighter tolerance (±5% versus ±10%) while maintaining all other electrical parameters. The improved tolerance grade provides enhanced voltage regulation precision. Packaging is Cut Tape format. This part does not carry automotive-grade qualification. Inventory availability is highest among all substitutes (27300 pieces). Selection is appropriate for applications requiring tighter voltage tolerance specifications.

SML4738AHE3_A/H (±5% Tolerance, Tape & Reel)

This substitute provides tighter tolerance (±5%) and maintains Tape & Reel packaging identical to the main part. Automotive-grade qualification (AEC-Q101) is present, matching the main part's qualification status. Selection is appropriate for automotive applications or when both tighter tolerance and Tape & Reel packaging are required. Inventory is 2287 pieces.

Selection Criteria Summary:

For applications requiring automotive-grade components with AEC-Q101 qualification, select either SML4738HE3_A/I (main part) or SML4738AHE3_A/H (substitute with tighter tolerance). For non-automotive applications where tighter tolerance is beneficial, SML4738A-E3/61 offers the highest inventory availability. For packaging format flexibility, SML4738-E3/5A provides Cut Tape alternative with standard-grade qualification.

Frequently Asked Questions (FAQ)

Q: Can SML4738-E3/5A be used as a direct replacement for SML4738HE3_A/I?

A: Yes. Both parts share identical electrical specifications (8.2 V, 1 W, ±10% tolerance, 4.5 Ohms impedance, 10 µA reverse leakage). The primary difference is packaging format: SML4738-E3/5A is supplied in Cut Tape while SML4738HE3_A/I is supplied in Tape & Reel. Both are RoHS3 compliant with MSL 1. For non-automotive applications, this substitution is electrically and mechanically compatible.

Q: What is the difference between ±10% and ±5% tolerance variants?

A: Tolerance specifies the allowable deviation from the nominal 8.2 V Zener voltage. SML4738HE3_A/I and SML4738-E3/5A have ±10% tolerance, allowing voltage between 7.38 V and 9.02 V. SML4738A-E3/61 and SML4738AHE3_A/H have ±5% tolerance, allowing voltage between 7.79 V and 8.61 V. Tighter tolerance (±5%) provides more precise voltage regulation and is suitable for applications with strict voltage specifications.

Q: Are all substitute parts automotive-qualified?

A: No. Only SML4738HE3_A/I (main part) and SML4738AHE3_A/H carry AEC-Q101 automotive qualification. SML4738-E3/5A and SML4738A-E3/61 are standard-grade parts without automotive qualification. For automotive applications, use only AEC-Q101 qualified variants.

Q: What is the difference between Tape & Reel and Cut Tape packaging?

A: Tape & Reel (TR) packaging supplies components on continuous tape wound on reels, suitable for high-volume automated assembly. Cut Tape (CT) packaging supplies components on tape segments cut to specific lengths, suitable for lower-volume or manual assembly processes. Both formats use identical DO-214AC (SMA) component packages and are mechanically compatible with standard surface mount equipment.

Q: Can I substitute a ±5% tolerance part for a ±10% tolerance requirement?

A: Yes. A ±5% tolerance part exceeds the specifications of a ±10% tolerance requirement. SML4738A-E3/61 or SML4738AHE3_A/H can replace SML4738HE3_A/I in any application. The tighter tolerance provides equal or better performance.

Q: Are all parts RoHS3 compliant?

A: Yes. All parts listed (SML4738HE3_A/I, SML4738-E3/5A, SML4738A-E3/61, and SML4738AHE3_A/H) are RoHS3 compliant with MSL 1 (Unlimited moisture sensitivity level).

Q: Which substitute has the best inventory availability?

A: SML4738A-E3/61 has the highest inventory with 27300 pieces in stock. This part offers ±5% tolerance in Cut Tape format without automotive qualification.

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