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1.5KE91A Transient Voltage Suppressor (TVS) Diode – Equivalent & Substitute Parts
Part Overview
The 1.5KE91A is a unidirectional Zener transient voltage suppressor diode manufactured by Diodes Incorporated, designed for general-purpose overvoltage protection in through-hole applications. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The 1.5KE91A operates with a reverse standoff voltage of 77.8V, breakdown voltage minimum of 86.5V, and peak pulse current rating of 12A at 1500W peak pulse power. The device is housed in a DO-201AA/DO-27 axial package and is ROHS3 compliant with unlimited moisture sensitivity level (MSL 1).
Substiute Parts
Key Parameters
| Parameter | Value | Unit |
|---|---|---|
| Voltage – Reverse Standoff (Typ) | 77.8 | V |
| Voltage – Breakdown (Min) | 86.5 | V |
| Voltage – Clamping (Max) @ Ipp | 125 | V |
| Current – Peak Pulse (10/1000µs) | 12 | A |
| Power – Peak Pulse | 1500 | W |
| Operating Temperature Range | -55 to 175 | °C |
| Mounting Type | Through Hole | – |
| Package / Case | DO-201AA, DO-27, Axial | – |
| Type | Zener | – |
| Unidirectional Channels | 1 | – |
| RoHS Status | ROHS3 Compliant | – |
| MSL Rating | 1 (Unlimited) | – |
Substitute Part Grouping Explanation
Substitute parts for the 1.5KE91A are qualified based on the following electrical and mechanical parameters:
Critical Matching Parameters:
- Voltage – Reverse Standoff (Typ): 77.8V
- Voltage – Breakdown (Min): 86.5V (±0.15V tolerance acceptable)
- Voltage – Clamping (Max) @ Ipp: 125V
- Current – Peak Pulse (10/1000µs): 12A (±0.6A tolerance acceptable)
- Power – Peak Pulse: 1500W
- Operating Temperature Range: -55°C to 175°C (or -55°C to 150°C minimum)
- Mounting Type: Through Hole
- Package / Case: DO-201AA, DO-27, or Axial equivalent
- Type: Zener, Unidirectional
- RoHS Status: ROHS3 Compliant
Substitute parts are grouped into three categories:
Category 1: Direct Electrical & Mechanical Equivalents (Vishay TransZorb® Series) Parts 1.5KE91A-E3/54, 1.5KE91AHE3_A/C, 1N6294A-E3/54, and 1N6294AHE3_A/C meet all electrical specifications and package requirements. The 1N6294 series represents an alternative base product number designation for the same electrical performance. Parts designated with "HE3_A/C" include automotive-grade qualification (AEC-Q101).
Category 2: Manufacturer Alternatives (Active Production) Parts from Taiwan Semiconductor Corporation (1.5KE91A), Littelfuse Inc. (1.5KE91A-B, 1.5KE91A-TB), Comchip Technology (1.5KE91A-G, 1.5KE91A-HF), and Fairchild Semiconductor (1V5KE91A) provide electrical equivalence with variations in peak pulse current tolerance (12A to 12.6A) and operating temperature upper limits (150°C to 175°C).
Category 3: Packaging Variants Substitute parts differ in packaging format (Bulk, Tape & Reel, Tape & Box, Cut Tape) but maintain identical electrical performance and through-hole axial package form factor.
Parameter Comparison
| Part Number | Manufacturer | VWM (Typ) V | VBR (Min) V | VC (Max) V | Ipp (10/1000µs) A | Power W | Temp Range °C | Package | Status | RoHS |
|---|---|---|---|---|---|---|---|---|---|---|
| 1.5KE91A-T | Diodes Inc. | 77.8 | 86.5 | 125 | 12 | 1500 | -55 to 175 | DO-201AA | Obsolete | ROHS3 |
| 1.5KE91A-E3/54 | Vishay | 77.8 | 86.5 | 125 | 12 | 1500 | -55 to 175 | DO-201AA | Active | ROHS3 |
| 1.5KE91AHE3_A/C | Vishay | 77.8 | 86.5 | 125 | 12 | 1500 | -55 to 175 | DO-201AA | Active | ROHS3 |
| 1N6294A-E3/54 | Vishay | 77.8 | 86.5 | 125 | 12 | 1500 | -55 to 175 | DO-201AA | Active | ROHS3 |
| 1N6294AHE3_A/C | Vishay | 77.8 | 86.5 | 125 | 12 | 1500 | -55 to 175 | DO-201AA | Active | ROHS3 |
| 1V5KE91A | Fairchild | 77.8 | 86.5 | 125 | 12 | 1500 | -55 to 175 | DO-201AD | Active | – |
| 1.5KE91A | Taiwan Semi | 77.8 | 86.5 | 125 | 12.6 | 1500 | -55 to 175 | DO-201AA | Active | ROHS3 |
| 1.5KE91A-B | Littelfuse | 77.8 | 86.5 | 125 | 12.2 | 1500 | -55 to 175 | DO-201AA | Active | ROHS3 |
| 1.5KE91A-G | Comchip | 77.8 | 86.45 | 125 | 12 | 1500 | -55 to 150 | DO-201AA | Active | ROHS3 |
| 1.5KE91A-HF | Comchip | 77.8 | 86.45 | 125 | 12 | 1500 | -55 to 150 | DO-201AA | Active | ROHS3 |
| 1.5KE91A-TB | Littelfuse | 77.8 | 86.5 | 125 | 12.2 | 1500 | -55 to 175 | DO-201AA | Active | ROHS3 |
Engineering Selection Recommendations
Primary Recommendation – Vishay TransZorb® Series (1.5KE91A-E3/54, 1.5KE91AHE3_A/C)
The Vishay 1.5KE91A-E3/54 and 1.5KE91AHE3_A/C are the preferred direct substitutes. Both maintain exact electrical specifications matching the obsolete 1.5KE91A-T, with active product status and full ROHS3 compliance. The 1.5KE91AHE3_A/C variant includes AEC-Q101 automotive qualification, suitable for applications requiring automotive-grade reliability. Inventory availability is strong (4000 pcs and 988 pcs respectively).
Secondary Recommendation – Taiwan Semiconductor Corporation (1.5KE91A)
The Taiwan Semiconductor 1.5KE91A offers the highest inventory availability (20,200 pcs) with active production status. Peak pulse current is rated at 12.6A, providing 5% margin above the original 12A specification. Operating temperature range matches the original (-55°C to 175°C). This part is suitable for applications where higher current margin is beneficial.
Alternative Recommendation – Littelfuse Inc. (1.5KE91A-B, 1.5KE91A-TB)
Littelfuse parts 1.5KE91A-B and 1.5KE91A-TB provide active alternatives with peak pulse current of 12.2A and full temperature range support (-55°C to 175°C). The -TB variant is packaged in Tape & Box format, suitable for automated assembly environments.
Temperature-Constrained Applications – Comchip Technology (1.5KE91A-G, 1.5KE91A-HF)
Comchip parts 1.5KE91A-G and 1.5KE91A-HF are suitable only for applications with maximum operating temperature of 150°C. Breakdown voltage is specified at 86.45V (within tolerance). These parts are not recommended for designs requiring the full -55°C to 175°C temperature range.
Alternative Base Number – Vishay 1N6294 Series
Parts 1N6294A-E3/54 and 1N6294AHE3_A/C represent an alternative base product designation from Vishay with identical electrical performance. These are functionally equivalent to the 1.5KE91A series and may be used interchangeably where design documentation permits alternative part number designations.
Not Recommended – Fairchild 1V5KE91A
The Fairchild 1V5KE91A lacks documented RoHS compliance status and is not recommended for new designs or applications with RoHS requirements.
Frequently Asked Questions (FAQ)
Q: Can I substitute the obsolete 1.5KE91A-T with any of the listed alternatives?
A: Yes. All listed alternatives meet the critical electrical parameters: 77.8V reverse standoff voltage, 86.5V minimum breakdown voltage, 125V maximum clamping voltage, and 12A peak pulse current (with minor tolerance variations). All are through-hole axial package devices in DO-201AA or equivalent form factor. Verify your design documentation permits alternative manufacturer part numbers.
Q: What is the difference between 1.5KE91A and 1N6294A?
A: Both are Vishay TransZorb® devices with identical electrical specifications. The 1N6294 designation represents an alternative base product number for the same 91V clamping voltage class. They are functionally interchangeable. Consult Vishay documentation to confirm compatibility with your specific application.
Q: Are the Comchip 1.5KE91A-G and 1.5KE91A-HF suitable for high-temperature applications?
A: No. Comchip parts are rated to 150°C maximum junction temperature, compared to 175°C for most alternatives. If your application requires operation above 150°C, select Vishay, Taiwan Semiconductor, or Littelfuse alternatives.
Q: What is the significance of the "HE3_A/C" suffix on Vishay parts?
A: The HE3_A/C designation indicates AEC-Q101 automotive qualification. These parts meet automotive reliability and qualification standards. Use these variants for automotive or safety-critical applications requiring automotive-grade component certification.
Q: Does packaging format affect electrical performance?
A: No. Packaging format (Bulk, Tape & Reel, Tape & Box, Cut Tape) affects handling, storage, and assembly processes but does not alter electrical specifications. Select packaging based on your procurement and assembly requirements.
Q: Why does Taiwan Semiconductor list 12.6A peak pulse current instead of 12A?
A: Taiwan Semiconductor specifies 12.6A peak pulse current, which is within acceptable tolerance for the 1.5KE91 series. This represents a 5% margin above the nominal 12A specification and does not affect substitution compatibility.
Q: Can I use 1.5KE91A-E3/54 in place of 1.5KE91AHE3_A/C?
A: Yes, electrically. However, 1.5KE91AHE3_A/C includes AEC-Q101 automotive qualification. If your application or procurement specification requires automotive-grade components, use the HE3_A/C variant. For general-purpose applications, both are equivalent.
Q: Is the 1V5KE91A from Fairchild a suitable substitute?
A: The Fairchild 1V5KE91A meets electrical specifications but lacks documented RoHS compliance status. It is not recommended for new designs or applications with RoHS requirements. Prefer Vishay, Taiwan Semiconductor, Littelfuse, or Comchip alternatives.
Q: What inventory considerations should I account for?
A: Taiwan Semiconductor offers the highest inventory (20,200 pcs), followed by Vishay 1.5KE91A-E3/54 (4000 pcs). Littelfuse and Comchip alternatives range from 818 to 1034 pcs. Verify current availability with your supplier before finalizing procurement decisions.
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