1N5997B-TP Zener Diode Equivalent & Substitute Parts

Part Overview

The 1N5997B-TP is a 7.5 V, 500 mW Zener diode manufactured by Micro Commercial Co in a DO-35 (DO-204AH) axial through-hole package. This component is classified as obsolete, necessitating identification of active equivalent and substitute parts for ongoing design support and procurement. The 1N5997B-TP operates across a temperature range of -65°C to 200°C with ±5% voltage tolerance and is ROHS3 compliant. Equivalent parts maintain identical electrical specifications, while substitute parts offer comparable performance within acceptable parameter variations for zener diode applications.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nominal)	7.5	V
Tolerance	±5	%
Power - Maximum	500	mW
Impedance (Maximum)	7	Ohms
Current - Reverse Leakage @ Vr	500	nA @ 6 V
Voltage - Forward (Maximum) @ If	1.5	V @ 100 mA
Operating Temperature Range	-65 to 200	°C
Mounting Type	Through Hole
Package / Case	DO-204AH, DO-35, Axial

Substitute Part Grouping Explanation

Zener diode substitution is determined by the following critical parameters: nominal zener voltage (Vz), power dissipation rating (P-Max), voltage tolerance, operating temperature range, and physical package compatibility. Parts are classified into two categories:

Direct Equivalents (500 mW, DO-35 Package): Parts maintaining identical 7.5 V nominal voltage, 500 mW power rating, and DO-35 package form factor. These parts are pin-compatible and functionally interchangeable with the 1N5997B-TP.

Similar Substitutes (1 W, DO-41 Package): Parts with matching 7.5 V nominal voltage and ±5% tolerance but higher 1 W power rating in DO-41 package. These are suitable for applications where increased power dissipation capability is acceptable and mechanical package change is feasible.

The following parameters determine substitution validity:

Nominal Zener Voltage: 7.5 V (required match)
Voltage Tolerance: ±5% (required match)
Operating Temperature: -65°C minimum and 200°C maximum (required match or better)
Package Type: DO-35 for direct equivalents; DO-41 for higher-power alternatives
Mounting: Through Hole (required match)

Parameter Comparison

Part Number	Manufacturer	Vz (V)	Tolerance (%)	P-Max (mW)	Zzt (Ohms)	Ir @ Vr (nA/µA)	Vf @ If (V)	Temp Range (°C)	Package	Status
1N5997B-TP	Micro Commercial Co	7.5	±5	500	7	500 nA @ 6 V	1.5 @ 100 mA	-65 to 200	DO-35	Obsolete
1N5236BTR	Fairchild Semiconductor	7.5	±5	500	6	3 µA @ 6 V	1.2 @ 200 mA	-65 to 200	DO-35	Active
1N5997B TR PBFREE	Central Semiconductor Corp	7.5	±5	500	7	500 nA @ 6 V	1.5 @ 100 mA	-65 to 200	DO-35	Active
1N5236B	Microchip Technology	7.5	±5	500	6	3 µA @ 6 V	1.5 @ 200 mA	-65 to 175	DO-35	Active
1N5236B-TR	Vishay General Semiconductor - Diodes Division	7.5	±5	500	6	3 µA @ 6 V	1.1 @ 200 mA	-65 to 200	DO-35	Active
TZX7V5A-TAP	Vishay General Semiconductor - Diodes Division	7.5	-	500	15	1 µA @ 5 V	1.5 @ 200 mA	-65 to 175	DO-35	Active
TZX7V5A-TR	Vishay General Semiconductor - Diodes Division	7.5	-	500	15	1 µA @ 5 V	1.5 @ 200 mA	-65 to 175	DO-35	Active
TZX7V5B-TR	Vishay General Semiconductor - Diodes Division	7.5	-	500	15	1 µA @ 5 V	1.5 @ 200 mA	-65 to 175	DO-35	Active
TZX7V5C-TAP	Vishay General Semiconductor - Diodes Division	7.5	-	500	15	1 µA @ 5 V	1.5 @ 200 mA	-65 to 175	DO-35	Active
1N4737A	Lumimax Optoelectronic Technology	7.5	±5	1000	4	10 µA @ 5 V	1.2 @ 200 mA	-65 to 200	DO-41	Active
1N4737ATR	Fairchild Semiconductor	7.5	±5	1000	4	10 µA @ 5 V	-	-65 to 200	DO-41	Active

Engineering Selection Recommendations

Primary Equivalent Selection:

The 1N5997B TR PBFREE (Central Semiconductor Corp) is the direct functional equivalent to the obsolete 1N5997B-TP. This part maintains identical electrical specifications including 7.5 V nominal voltage, 500 mW power rating, 7 Ohms maximum impedance, and 500 nA reverse leakage current. Operating temperature range matches the original (-65°C to 200°C), and the part is ROHS3 compliant with REACH unaffected status. This part is currently active in production.

Secondary Equivalent Options:

The 1N5236BTR (Fairchild Semiconductor) and 1N5236B-TR (Vishay) are functionally equivalent with identical voltage and power specifications. Both maintain -65°C to 200°C operating range and are ROHS3 compliant. These parts feature lower impedance (6 Ohms) and reduced reverse leakage (3 µA @ 6 V) compared to the original specification, representing improved performance characteristics. The 1N5236B-TR includes ROHS3 compliance and unlimited moisture sensitivity level (MSL 1).

Automotive-Grade Alternative:

The TZX7V5 series (Vishay, variants A-TAP, A-TR, B-TR, C-TAP) provides automotive-qualified alternatives with AEC-Q101 certification. These parts maintain 7.5 V nominal voltage and 500 mW power rating in DO-35 package. Operating temperature is limited to -65°C to 175°C, which is acceptable for applications not requiring the full 200°C upper limit. Higher impedance (15 Ohms) and lower reverse leakage (1 µA @ 5 V) are provided. ROHS3 compliance is confirmed for all variants.

Higher Power Alternative:

The 1N4737A and 1N4737ATR (1 W, DO-41 package) are suitable substitutes where increased power dissipation is required. Both maintain 7.5 V nominal voltage and ±5% tolerance with -65°C to 200°C operating range. The DO-41 package is physically larger than DO-35, requiring mechanical board layout modification. These parts are appropriate for applications with higher thermal demands.

Compliance Considerations:

All recommended active substitutes maintain ROHS3 compliance and REACH unaffected status. The 1N5236B (Microchip) is noted as RoHS non-compliant and should be avoided in applications requiring RoHS certification. Selection should prioritize parts with confirmed ROHS3 status for regulatory compliance.

Frequently Asked Questions (FAQ)

Q: Can the 1N5997B-TP be directly replaced with the 1N5236BTR?

A: Yes. Both parts share identical nominal zener voltage (7.5 V), voltage tolerance (±5%), power rating (500 mW), and DO-35 package configuration. The 1N5236BTR is pin-compatible and functionally equivalent. The 1N5236BTR features lower impedance and reverse leakage, representing improved performance within the same electrical class.

Q: What is the difference between the 1N5236B and 1N5236B-TR?

A: Both parts are electrically identical with 7.5 V nominal voltage, 500 mW power rating, and DO-35 package. The primary difference is packaging format: 1N5236B is supplied in bulk, while 1N5236B-TR is supplied in cut tape format. Selection depends on assembly process requirements. The 1N5236B-TR includes ROHS3 compliance confirmation.

Q: Why do the TZX7V5 series parts have higher impedance (15 Ohms) than the original 1N5997B-TP (7 Ohms)?

A: The TZX7V5 series represents a different design generation with different impedance characteristics. Higher impedance does not prevent functional substitution in most applications. Impedance affects voltage regulation performance under load changes. Applications sensitive to impedance specifications should be evaluated individually.

Q: Can the 1N4737A (1 W, DO-41) replace the 1N5997B-TP (500 mW, DO-35)?

A: The 1N4737A is electrically compatible with identical 7.5 V nominal voltage and ±5% tolerance. However, the DO-41 package is physically larger than DO-35, requiring board layout modification. The 1 W power rating provides higher thermal capacity, suitable for applications with increased power dissipation requirements. This substitution requires mechanical design review.

Q: Are all substitute parts ROHS3 compliant?

A: No. The 1N5236B (Microchip) is noted as RoHS non-compliant. All other recommended substitutes including 1N5236BTR, 1N5236B-TR, TZX7V5 series variants, and 1N4737 series are ROHS3 compliant. Regulatory requirements should determine part selection.

Q: What is the significance of the AEC-Q101 qualification on TZX7V5 parts?

A: AEC-Q101 is an automotive industry qualification standard. TZX7V5 series parts meeting this qualification are suitable for automotive applications requiring enhanced reliability and quality assurance. Non-automotive applications do not require this qualification.

Q: Does the operating temperature range difference between parts affect substitution?

A: The 1N5997B-TP operates to 200°C maximum. The 1N5236B (Microchip) and TZX7V5 series are limited to 175°C maximum. For applications operating above 175°C, the 1N5236BTR (Fairchild), 1N5236B-TR (Vishay), 1N5997B TR PBFREE (Central Semiconductor), 1N4737A, and 1N4737ATR maintain the full -65°C to 200°C range and are preferred.

Q: What packaging formats are available for equivalent parts?

A: Equivalent parts are supplied in multiple formats: bulk (loose components), cut tape (CT), tape and reel (TR), and tape and box (TB). Selection depends on assembly process and volume requirements. Tape and reel formats are standard for automated assembly; bulk formats are used for manual assembly or low-volume applications.

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