1N4749A-T Zener Diode Equivalent & Substitute Parts

Part Overview

The 1N4749A-T is a 24 V, 1 W zener diode manufactured by Diodes Incorporated in DO-41 through-hole package configuration. This component is classified as obsolete, necessitating identification of active equivalent and substitute parts for ongoing design requirements and production continuity. The 1N4749A-T serves voltage regulation and protection functions in electronic circuits requiring stable 24 V reference voltage with 1 W power dissipation capability.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	24	V
Tolerance	±5	%
Power - Maximum	1	W
Impedance (Maximum)	25	Ohms
Current - Reverse Leakage @ Vr	5	µA @ 18.2 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 1N4749A-T is determined by electrical and mechanical parameter equivalence. The critical parameters defining substitutability are:

Electrical Parameters:

Zener voltage: 24 V nominal
Tolerance: ±5%
Power rating: 1 W minimum
Impedance: 25 Ohms maximum
Reverse leakage current: 5 µA @ 18.2 V
Forward voltage: 1.2 V @ 200 mA maximum

Mechanical Parameters:

Mounting type: Through Hole
Package designation: DO-41 or DO-204AL (equivalent designations)

Compliance Parameters:

RoHS status: ROHS3 Compliant or RoHS Compliant
REACH status: REACH Unaffected or REACH Affected
Moisture Sensitivity Level: 1 (Unlimited)

Parts meeting all electrical specifications within stated tolerances and maintaining through-hole DO-41 package compatibility are classified as direct substitutes. Parts with enhanced power ratings (1.25 W or 3 W) or extended temperature ranges are classified as upgrades, providing superior performance margins while maintaining electrical compatibility.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Vz (V)	Tolerance (%)	Power (W)	Zzt (Ohms)	Ir @ Vr (µA)	Vf @ If (V)	Temp Range (°C)	Package	Status
1N4749A-T	Diodes Incorporated	24	±5	1	25	5 @ 18.2	1.2 @ 200mA	-65 to 175	DO-41	Obsolete
1N4749A	Lumimax Optoelectronic Technology	24	±5	1	25	5 @ 18.2	1.2 @ 200mA	-65 to 200	DO-41G	Active
1N4749A,113	Nexperia USA Inc.	24	±5	1	25	5 @ 18.2	1.2 @ 200mA	-65 to 200	DO-41	Active
1N4749AP/TR8	Microchip Technology	24	±5	1	25	5 @ 18.2	1.2 @ 200mA	-65 to 150	DO-204AL	Active
1N4749A,133	NXP Semiconductors	24	±5	1	25	5 @ 18.2	1.2 @ 200mA	-65 to 200	DO-41	Active
1N4749A-T50A	onsemi	24	±5	1	25	5 @ 18.2	Not specified	-65 to 200	DO-41	Active
1N4749A-T50R	onsemi	24	±5	1	25	5 @ 18.2	Not specified	-65 to 200	DO-41	Obsolete
1N4749ATR	Fairchild Semiconductor	24	±5	1	25	5 @ 18.2	Not specified	-65 to 200	DO-204AL	Active
1N4749AGE3	Microchip Technology	24	±5	1	25	5 @ 18.2	1.2 @ 200mA	-65 to 175	DO-41	Active
1N5934B3P-TP	Micro Commercial Co	24	±5	3	19	1 @ 18.2	1.5 @ 200mA	-55 to 150	DO-41	Active
1N5934BG	Microsemi Corporation	24	±5	1.25	19	1 @ 18.2	1.2 @ 200mA	-65 to 175	DO-204AL	Active

Engineering Selection Recommendations

Direct Substitutes (Equivalent Electrical and Mechanical Performance):

The following parts provide direct substitution for the 1N4749A-T with active product status and full electrical parameter equivalence:

1N4749A,113 (Nexperia USA Inc.) - Active status, ROHS3 compliant, extended temperature range to 200°C, Cut Tape packaging available
1N4749A (Lumimax Optoelectronic Technology) - Active status, extended temperature range to 200°C, high inventory availability (37,200 units)
1N4749A,133 (NXP Semiconductors) - Active status, extended temperature range to 200°C, high inventory availability (58,496 units)

Compatible Substitutes (Equivalent Electrical Performance, Package Variants):

1N4749AP/TR8 (Microchip Technology) - Active status, DO-204AL package variant, Tape & Reel packaging, temperature range -65°C to 150°C
1N4749ATR (Fairchild Semiconductor) - Active status, DO-204AL package variant, extended temperature range to 200°C, high inventory availability (24,885 units)

Upgrade Options (Enhanced Performance Margins):

1N5934BG (Microsemi Corporation) - Active status, 1.25 W power rating (25% margin increase), lower impedance (19 Ohms), reduced reverse leakage (1 µA), DO-204AL package
1N5934B3P-TP (Micro Commercial Co) - Active status, 3 W power rating (200% margin increase), lower impedance (19 Ohms), reduced reverse leakage (1 µA), suitable for high-stress applications

Compliance Considerations:

1N4749A,113, 1N4749A-T50A, and 1N4749A-T50R are ROHS3 compliant
1N4749AGE3 is ROHS3 compliant
1N4749AP/TR8 is RoHS non-compliant
1N5934BG is RoHS non-compliant
All listed parts are REACH Unaffected except 1N4749A-T (REACH Affected)

Frequently Asked Questions (FAQ)

Q: Can I directly replace 1N4749A-T with 1N4749A,113?

A: Yes. The 1N4749A,113 meets all electrical specifications of the 1N4749A-T (24 V nominal, ±5% tolerance, 1 W power, 25 Ohms impedance, 5 µA reverse leakage, 1.2 V forward voltage). Both use DO-41 through-hole packages. The 1N4749A,113 is active status with extended temperature range (-65°C to 200°C versus -65°C to 175°C) and ROHS3 compliance.

Q: What is the difference between DO-41 and DO-204AL packages?

A: DO-41 and DO-204AL are equivalent designations for the same axial through-hole package used for zener diodes. Both refer to a two-lead axial component with identical physical dimensions and pin spacing. Parts specified as either designation are mechanically interchangeable.

Q: Why would I select 1N5934BG over a direct 1N4749A substitute?

A: The 1N5934BG provides enhanced performance margins with 1.25 W power rating (versus 1 W), lower impedance (19 Ohms versus 25 Ohms), and reduced reverse leakage current (1 µA versus 5 µA). Selection of this upgrade is appropriate for applications requiring improved thermal performance, lower dynamic impedance, or reduced leakage in high-impedance circuits.

Q: Are there RoHS compliance differences between substitute options?

A: Yes. Direct substitutes 1N4749A,113, 1N4749A-T50A, and 1N4749AGE3 are ROHS3 compliant. The 1N4749AP/TR8 and 1N5934BG are RoHS non-compliant. Selection depends on end-product RoHS requirements. The original 1N4749A-T is ROHS3 compliant.

Q: Can I use 1N4749AP/TR8 if my circuit requires -65°C to 175°C operation?

A: The 1N4749AP/TR8 has a maximum operating temperature of 150°C, which does not meet the -65°C to 175°C requirement of the original 1N4749A-T. Alternative selections include 1N4749A,113, 1N4749A, 1N4749A,133, or 1N4749ATR, all rated to 200°C minimum.

Q: What packaging format should I specify for automated assembly?

A: For automated pick-and-place assembly, specify Tape & Reel (TR) packaging. The 1N4749AP/TR8 is available in Tape & Reel format. For manual assembly or through-hole insertion, bulk or cut tape packaging is acceptable. Verify your assembly equipment compatibility with selected packaging format.

Q: Is 1N4749A-T50R still available for new designs?

A: No. The 1N4749A-T50R is classified as obsolete. Although 894 units remain in inventory, this part should not be selected for new designs. Use active alternatives such as 1N4749A-T50A (same manufacturer, active status) or other listed active substitutes.

Q: How do I determine if a substitute part is suitable for my specific application?

A: Verify that the substitute part meets or exceeds all critical parameters: zener voltage (24 V), tolerance (±5%), power rating (minimum 1 W), operating temperature range, and package type (DO-41 or DO-204AL). Cross-reference the substitute part's datasheet against your circuit requirements for forward voltage, reverse leakage, and impedance specifications.

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