SML4746HE3_A/I Zener Diode 18V 1W Equivalent & Substitute Parts

Part Overview

The SML4746HE3_A/I is an 18V 1W surface mount zener diode manufactured by Vishay General Semiconductor - Diodes Division in the DO-214AC (SMA) package. This component is classified as an active product with automotive-grade qualification (AEC-Q101) and is RoHS3 compliant. The device operates at a maximum temperature of 150°C with a nominal zener voltage of 18V and ±10% tolerance. Substitute parts are necessary when specific packaging formats, tolerance requirements, or inventory availability differ from the primary part specification.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	18	V
Tolerance	±10%	—
Power - Maximum	1	W
Impedance (Maximum)	20	Ohms
Current - Reverse Leakage @ Vr	5	µA @ 13.7 V
Operating Temperature	150	°C
Package / Case	DO-214AC (SMA)	—
Mounting Type	Surface Mount	—
Grade	Automotive	—
Qualification	AEC-Q101	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the SML4746HE3_A/I is determined by the following critical parameters: zener voltage (18V nominal), maximum power dissipation (1W), package type (DO-214AC/SMA), mounting configuration (surface mount), and tolerance specification (±10%). All substitute parts maintain identical zener voltage, power rating, package, and mounting type. Variations occur in tolerance class (±10% versus ±5%), packaging format (Tape & Reel versus Cut Tape), and automotive qualification status. Parts with ±5% tolerance provide tighter voltage regulation and are direct substitutes for applications requiring improved accuracy. Packaging format differences (TR versus CT) affect supply chain logistics but do not impact electrical performance or board-level compatibility.

Parameter Comparison

Manufacturer Part Number	Vz (Nominal)	Tolerance	Power (Max)	Zzt (Max)	Packaging	Grade	AEC-Q101	Inventory (Pcs)
SML4746HE3_A/I	18 V	±10%	1 W	20 Ohms	Tape & Reel (TR)	Automotive	Yes	8464
SML4746-E3/5A	18 V	±10%	1 W	20 Ohms	Tape & Reel (TR)	—	No	8316
SML4746-E3/61	18 V	±10%	1 W	20 Ohms	Cut Tape (CT)	—	No	4571
SML4746A-E3/5A	18 V	±5%	1 W	20 Ohms	Tape & Reel (TR)	—	No	1494
SML4746A-E3/61	18 V	±5%	1 W	20 Ohms	Cut Tape (CT) & Digi-Reel®	—	No	36200
SML4746AHE3_A/H	18 V	±5%	1 W	20 Ohms	Tape & Reel (TR)	Automotive	Yes	1696

Engineering Selection Recommendations

Direct Electrical Equivalent (±10% Tolerance): The SML4746-E3/5A and SML4746-E3/61 are parametric equivalents with identical electrical specifications to the SML4746HE3_A/I. Selection between these parts depends on packaging format requirements. The SML4746-E3/5A is supplied in Tape & Reel format, while SML4746-E3/61 is supplied in Cut Tape format. Neither part carries automotive qualification or AEC-Q101 certification.

Tighter Tolerance Alternative (±5% Tolerance): The SML4746A-E3/5A and SML4746A-E3/61 provide improved voltage regulation with ±5% tolerance specification. These parts are suitable for applications requiring tighter zener voltage control. The SML4746A-E3/61 offers the highest inventory availability (36,200 pcs) and is available in Cut Tape and Digi-Reel® packaging.

Automotive-Grade Equivalent (±5% Tolerance): The SML4746AHE3_A/H is an automotive-grade substitute with AEC-Q101 qualification, ±5% tolerance, and Tape & Reel packaging. This part maintains the same automotive and compliance certifications as the primary part while providing improved voltage tolerance.

Compliance Considerations: All substitute parts maintain RoHS3 compliance, MSL Level 1 (Unlimited), and REACH Unaffected status. Automotive applications requiring AEC-Q101 qualification should select either SML4746HE3_A/I (primary part) or SML4746AHE3_A/H (substitute).

Frequently Asked Questions (FAQ)

Q: Can SML4746-E3/5A be used as a direct replacement for SML4746HE3_A/I?

A: Yes, the SML4746-E3/5A is a parametric equivalent with identical zener voltage (18V), power rating (1W), impedance (20 Ohms), and package (DO-214AC/SMA). The primary difference is the absence of automotive-grade qualification and AEC-Q101 certification. For non-automotive applications, this substitution is valid.

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 operations. Electrical performance and board-level compatibility are identical between these packaging formats.

Q: Is the SML4746A-E3/61 suitable for automotive applications?

A: The SML4746A-E3/61 does not carry automotive-grade designation or AEC-Q101 qualification. For automotive applications, use SML4746HE3_A/I or SML4746AHE3_A/H.

Q: What advantage does ±5% tolerance provide over ±10% tolerance?

A: The ±5% tolerance specification (SML4746A series) provides tighter control of the nominal zener voltage compared to ±10% tolerance (SML4746 series). Applications requiring precise voltage regulation benefit from the narrower tolerance band. Both tolerance classes maintain identical maximum power dissipation, impedance, and leakage current specifications.

Q: Are all substitute parts RoHS3 compliant?

A: Yes, all listed substitute parts are RoHS3 compliant with MSL Level 1 (Unlimited) and REACH Unaffected status, matching the primary part specification.

Q: Which substitute part has the highest inventory availability?

A: The SML4746A-E3/61 has the highest inventory availability at 36,200 pcs. This part is supplied in Cut Tape and Digi-Reel® packaging with ±5% tolerance specification.

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