Littelfuse 20KPA28 TVS Diode Equivalent & Substitute Parts

Part Overview

The Littelfuse 20KPA28 is a unidirectional Zener-type transient voltage suppressor (TVS) diode designed for general-purpose overvoltage protection applications. This component features a 28V reverse standoff voltage with a 50.4V maximum clamping voltage and 420.8A peak pulse current capability in a through-hole P600 axial package. The part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. Substitute parts must maintain compatibility across the 28V voltage class while accommodating variations in clamping voltage, peak pulse current, and power dissipation ratings.

Substiute Parts

20KPA28

LittelfuseIn Stock: 117620KPA28 Datasheet

Current PartRFQ

20KPA28A

MDE Semiconductor IncIn Stock: 168420KPA28A Datasheet

DirectRFQ

3KP28A-TP

Micro Commercial CoIn Stock: 19123KP28A-TP Datasheet

MFR RecommendedRFQ

5KP28A-E3/54

Vishay General Semiconductor - Diodes DivisionIn Stock: 84415KP28A-E3/54 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 20KPA28 is determined by the following critical parameters:

Mandatory Compatibility Criteria:

• Voltage - Reverse Standoff (Typ): 28V (exact match required)
• Type: Zener, unidirectional
• Unidirectional Channels: 1
• Mounting Type: Through Hole
• Operating Temperature Range: -55°C to 175°C (TJ) minimum
• RoHS Status: ROHS3 Compliant

Allowable Variation Parameters:

• Voltage - Clamping (Max) @ Ipp: 45.4V to 50.4V (lower clamping voltages provide tighter protection margins)
• Current - Peak Pulse (10/1000µs): 110A to 420.8A (lower ratings acceptable for reduced surge current applications)
• Power - Peak Pulse: 3000W to 20000W (lower ratings acceptable for reduced power dissipation requirements)
• Package / Case: P600 or R-6 axial packages (both through-hole axial configurations)

The three substitute parts listed maintain the 28V voltage class and core Zener diode functionality while offering different performance levels across clamping voltage, peak pulse current, and power dissipation ratings.

Parameter Comparison

Engineering Selection Recommendations

20KPA28A (MDE Semiconductor Inc)

The 20KPA28A is a direct functional equivalent with active product status. It maintains identical peak pulse current (420.8A) and power dissipation (20000W) ratings while offering a slightly lower clamping voltage (48V vs. 50.4V), providing marginally tighter overvoltage protection. The P600 axial package ensures mechanical and electrical compatibility. This part is recommended as the primary replacement for the obsolete 20KPA28 in applications requiring maximum surge current handling capacity.

3KP28A-TP (Micro Commercial Co)

The 3KP28A-TP operates within the 28V voltage class with a clamping voltage of 45.4V, providing the tightest overvoltage protection margin among the three substitutes. Peak pulse current and power dissipation are reduced (specifications not fully provided and 3000W respectively), making this part suitable for applications with lower surge current requirements. The R-6 axial package is mechanically compatible with through-hole mounting. This part is recommended for designs where lower surge current handling is acceptable and tighter clamping voltage control is beneficial.

5KP28A-E3/54 (Vishay General Semiconductor - Diodes Division)

The 5KP28A-E3/54 is a TransZorb® series component maintaining the 28V voltage class with a 45.4V clamping voltage and 5000W power dissipation rating. Peak pulse current is rated at 110A, significantly lower than the original part. The P600 axial package provides direct mechanical compatibility. This part is recommended for applications with moderate surge current requirements where the reduced power dissipation rating is acceptable and the tighter clamping voltage is advantageous.

Frequently Asked Questions (FAQ)

Q: Can the 20KPA28A be used as a direct replacement for the obsolete 20KPA28?

A: Yes. The 20KPA28A maintains identical electrical performance across peak pulse current (420.8A) and power dissipation (20000W) ratings, operates within the same temperature range, and uses the same P600 axial package. The slightly lower clamping voltage (48V vs. 50.4V) provides equivalent or improved protection performance.

Q: What is the primary difference between the 20KPA28A and the 3KP28A-TP?

A: The 20KPA28A and 3KP28A-TP differ in peak pulse current handling and power dissipation. The 20KPA28A is rated for 420.8A and 20000W, while the 3KP28A-TP is rated for 3000W with unspecified peak pulse current. The 3KP28A-TP also uses an R-6 axial package instead of P600. Selection depends on the application's surge current and power dissipation requirements.

Q: Are all substitute parts compatible with the original 28V voltage class?

A: Yes. All substitute parts maintain a 28V reverse standoff voltage, ensuring compatibility with circuits designed for the 28V protection class. Clamping voltages vary between 45.4V and 50.4V, all within acceptable ranges for general-purpose overvoltage protection.

Q: What is the significance of the different package designations (P600 vs. R-6)?

A: Both P600 and R-6 are through-hole axial package formats suitable for PCB mounting. The primary difference is physical size and lead spacing. Verify PCB footprint compatibility before selecting a substitute with a different package designation.

Q: Which substitute part should be selected for maximum surge current handling?

A: The 20KPA28A maintains the original 420.8A peak pulse current rating and 20000W power dissipation, making it the appropriate choice for applications requiring maximum surge current handling capacity.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed carry ROHS3 Compliant status, meeting environmental and regulatory requirements equivalent to the original 20KPA28.