1N4738A-T Zener Diode Equivalent & Substitute Parts

Part Overview

The 1N4738A-T is an 8.2 V, 1 W Zener diode manufactured by Diodes Incorporated in DO-41 through-hole package. This component is classified as obsolete, necessitating identification of active equivalent and substitute parts for ongoing design requirements and procurement needs. The 1N4738A-T maintains electrical specifications consistent with the 1N4738 base product family, with multiple manufacturers offering functionally equivalent alternatives in active production status.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	8.2	V
Tolerance	±5	%
Power - Maximum	1	W
Impedance (Maximum)	4.5	Ohms
Current - Reverse Leakage @ Vr	10	µA @ 6 V
Voltage - Forward (Maximum) @ If	1.2	V @ 200 mA
Operating Temperature Range	-65 to 175	°C
Mounting Type	Through Hole
Package / Case	DO-204AL, DO-41, Axial

Substitute Part Grouping Explanation

Substitution of the 1N4738A-T is determined by strict equivalence across the following critical parameters:

Primary Substitution Criteria:

Voltage - Zener (Nominal): 8.2 V
Tolerance: ±5%
Power - Maximum: 1 W (or higher)
Impedance (Maximum): 4.5 Ohms
Current - Reverse Leakage @ Vr: 10 µA @ 6 V (or lower)
Voltage - Forward (Maximum) @ If: 1.2 V @ 200 mA (or lower)
Mounting Type: Through Hole
Package / Case: DO-204AL, DO-41, or Axial equivalent

Substitution Categories:

Direct Equivalents maintain all electrical specifications and differ only in manufacturer, packaging format, or product status transition from obsolete to active.

Upgrade Equivalents provide equal or superior electrical performance while maintaining compatibility with the original design envelope. These parts may feature extended operating temperature ranges or enhanced reliability certifications.

Higher Power Alternatives exceed the 1 W power specification while maintaining all other electrical parameters, suitable for applications requiring additional thermal margin.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Vz (V)	Tolerance (%)	Power (W)	Zzt (Ohms)	Ir @ Vr (µA)	Vf @ If (V)	Temp Range (°C)	Product Status	Packaging
1N4738A-T	Diodes Incorporated	8.2	±5	1	4.5	10 @ 6 V	1.2 @ 200 mA	-65 to 175	Obsolete	DO-41
1N4738A,113	Nexperia USA Inc.	8.2	±5	1	4.5	10 @ 6 V	1.2 @ 200 mA	-65 to 200	Active	Cut Tape (CT)
1N4738AP/TR8	Microchip Technology	8.2	±5	1	4.5	10 @ 6 V	1.2 @ 200 mA	-65 to 150	Active	Tape & Reel (TR)
1N4738A	Lumimax Optoelectronic Technology	8.2	±5	1	4.5	10 @ 6 V	1.2 @ 200 mA	-65 to 200	Active	Tape & Box (TB)
1N4738A,133	NXP Semiconductors	8.2	±5	1	4.5	10 @ 6 V	1.2 @ 200 mA	-65 to 200	Active	Bulk
1N4738A-T50A	onsemi	8.2	±5	1	4.5	10 @ 6 V	Not Specified	-65 to 200	Active	Tape & Box (TB)
1N4738A-T50R	Fairchild Semiconductor	8.2	±5	1	4.5	10 @ 6 V	Not Specified	-65 to 200	Active	Bulk
1N4738ATR	Fairchild Semiconductor	8.2	±5	1	4.5	10 @ 6 V	Not Specified	-65 to 200	Active	Bulk
1N4738A-TAP	Vishay General Semiconductor - Diodes Division	8.2	±5	1.3	4.5	10 @ 6 V	1.2 @ 200 mA	-65 to 175	Active	Cut Tape (CT)
1N4738AP/TR12	Microchip Technology	8.2	±5	1	4.5	10 @ 6 V	1.2 @ 200 mA	-65 to 150	Active	Tape & Reel (TR)
1N5923B3P-AP	Micro Commercial Co	8.2	±5	3	3.5	5 @ 6.5 V	1.5 @ 200 mA	-55 to 150	Active	Bulk

Engineering Selection Recommendations

Direct Replacement (Preferred for Obsolete Part Transition):

The following parts provide direct electrical and functional equivalence to the 1N4738A-T:

1N4738A,113 (Nexperia USA Inc.): Active status, extended operating temperature to 200°C, ROHS3 compliant, REACH unaffected. Cut Tape packaging suitable for automated assembly.
1N4738A,133 (NXP Semiconductors): Active status, extended operating temperature to 200°C, highest inventory availability (134,082 pcs), bulk packaging. REACH unaffected.
1N4738A (Lumimax Optoelectronic Technology): Active status, extended operating temperature to 200°C, high inventory (10,110 pcs), Tape & Box packaging.

Active Alternatives with Equivalent Specifications:

1N4738AP/TR8 and 1N4738AP/TR12 (Microchip Technology): Active status, Tape & Reel packaging for high-volume production. Operating temperature limited to 150°C. RoHS non-compliant status requires compliance verification for target application.
1N4738A-T50A (onsemi): Active status, extended operating temperature to 200°C, ROHS3 compliant, Tape & Box packaging.
1N4738A-T50R and 1N4738ATR (Fairchild Semiconductor): Active status, extended operating temperature to 200°C, bulk packaging.

Enhanced Performance Alternative:

1N4738A-TAP (Vishay General Semiconductor - Diodes Division): Active status, increased power rating (1.3 W vs. 1 W), AEC-Q101 automotive qualification, ROHS3 compliant. Suitable for applications requiring additional thermal margin or automotive-grade reliability.

Higher Power Alternative (Design Upgrade):

1N5923B3P-AP (Micro Commercial Co): 3 W power rating with 8.2 V nominal voltage. Lower impedance (3.5 Ohms) and reduced reverse leakage (5 µA @ 6.5 V). Operating temperature range -55°C to 150°C. Suitable for applications requiring increased power dissipation capability while maintaining voltage regulation specifications.

Frequently Asked Questions (FAQ)

Q: Can the 1N4738A-T be directly replaced with any of the listed substitute parts?

A: Yes. All listed substitute parts maintain the 8.2 V nominal voltage, ±5% tolerance, 1 W power rating (or higher), 4.5 Ohms maximum impedance, and through-hole DO-41 package compatibility. Direct substitution is electrically valid for all parts listed in the Parameter Comparison table.

Q: What is the difference between direct equivalents and upgrade equivalents?

A: Direct equivalents maintain identical electrical specifications and differ only in manufacturer or packaging format. Upgrade equivalents provide equal or superior performance, such as extended operating temperature ranges (-65°C to 200°C vs. -65°C to 175°C) or higher power ratings (1.3 W vs. 1 W), while remaining compatible with the original design.

Q: Why do some substitute parts have different operating temperature ranges?

A: Operating temperature range is a manufacturer-specific specification determined by device design and qualification testing. Parts with extended ranges (-65°C to 200°C) provide additional thermal margin. Parts with limited ranges (-65°C to 150°C) remain suitable for applications within those boundaries. Design requirements determine whether extended range is necessary.

Q: What packaging options are available for the 1N4738A-T substitutes?

A: Substitute parts are available in multiple packaging formats: Cut Tape (CT) for automated pick-and-place assembly, Tape & Reel (TR) for high-volume production, Tape & Box (TB) for moderate-volume applications, and Bulk for manual assembly or low-volume requirements. Package selection depends on production volume and assembly methodology.

Q: Is the 1N5923B3P-AP a suitable replacement for the 1N4738A-T?

A: The 1N5923B3P-AP maintains the 8.2 V nominal voltage and ±5% tolerance but provides 3 W power rating instead of 1 W. This part is suitable for applications requiring increased power dissipation. However, the lower operating temperature maximum (150°C vs. 175°C) and different impedance (3.5 Ohms vs. 4.5 Ohms) require verification against specific application requirements.

Q: What compliance certifications should be considered when selecting a substitute?

A: The original 1N4738A-T is ROHS3 compliant and REACH affected. Most substitute parts maintain ROHS3 compliance and REACH unaffected status. The 1N4738AP/TR8 and 1N4738AP/TR12 are RoHS non-compliant and require compliance verification for target applications. The 1N4738A-TAP includes AEC-Q101 automotive qualification for applications requiring automotive-grade reliability.

Q: Can the 1N4738A-T be used in applications requiring higher power dissipation?

A: The 1N4738A-T is rated for 1 W maximum power. For applications requiring higher power dissipation, the 1N4738A-TAP (1.3 W) or 1N5923B3P-AP (3 W) provide increased thermal capability while maintaining 8.2 V voltage regulation.

Q: Are there inventory considerations when selecting a substitute part?

A: Yes. Inventory availability varies significantly: 1N4738A,133 has the highest availability (134,082 pcs), while 1N4738AP/TR12 has limited availability (961 pcs). Procurement strategy should account for lead times and volume requirements based on specific inventory levels.

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