STL128DFP Equivalent & Substitute Parts

Part Overview

The STL128DFP is an NPN bipolar junction transistor manufactured by STMicroelectronics, rated for 400 V collector-emitter breakdown voltage and 4 A maximum collector current in a TO-220FP through-hole package. This device is classified as obsolete, necessitating identification of equivalent and substitute components for ongoing design requirements and procurement needs. The STL128DFP delivers 30 W maximum power dissipation and operates at junction temperatures up to 150°C.

Substiute Parts

STL128DFP

STMicroelectronicsIn Stock: 2937STL128DFP Datasheet

Current PartRFQ

STL128D

STMicroelectronicsIn Stock: 3688STL128D Datasheet

DirectRFQ

MJF18004G

onsemiIn Stock: 2190MJF18004G Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute relationships for the STL128DFP are established based on the following critical electrical and mechanical parameters:

Primary Substitution Criteria:

• Transistor type (NPN)
• Collector current rating (Ic ≥ 4 A)
• Collector-emitter breakdown voltage (VCEO ≥ 400 V)
• Power dissipation capability (P ≥ 30 W)
• Through-hole mounting configuration
• TO-220 package family compatibility

Substitution Categories:

Direct Substitute (STL128D): Maintains identical electrical specifications (4 A, 400 V, NPN) with enhanced power rating (65 W vs. 30 W) and active product status. Package variant differs (TO-220 vs. TO-220FP) but maintains mechanical compatibility within TO-220 family.

Similar Substitute (MJF18004G): Exceeds primary electrical specifications with higher collector current (5 A vs. 4 A), elevated breakdown voltage (450 V vs. 400 V), and comparable power rating (35 W vs. 30 W). Maintains NPN type and through-hole TO-220FP package. Introduces transition frequency specification (13 MHz) and extended temperature range (−65°C to 150°C).

Parameter Comparison

Engineering Selection Recommendations

STL128D Selection Rationale:

The STL128D is the primary direct substitute for the STL128DFP. Both components share identical electrical specifications (4 A collector current, 400 V breakdown voltage, NPN configuration) and are manufactured by STMicroelectronics. The STL128D holds active product status, ensuring long-term availability and supply chain continuity. Enhanced power rating (65 W vs. 30 W) provides additional thermal margin without compromising circuit compatibility. Package variant (TO-220 vs. TO-220FP) maintains mechanical interchangeability within the TO-220 family. Both devices carry ROHS3 compliance and REACH unaffected status, satisfying regulatory requirements.

MJF18004G Selection Rationale:

The MJF18004G functions as a similar substitute when enhanced electrical performance is acceptable or required. This onsemi component exceeds STL128DFP specifications in collector current (5 A), breakdown voltage (450 V), and power dissipation (35 W). The MJF18004G maintains active product status and ROHS3 compliance. Extended operating temperature range (−65°C to 150°C) accommodates broader environmental conditions. Transition frequency specification (13 MHz) indicates suitability for switching applications. Lower collector cutoff current (100µA vs. 250µA) reduces leakage in off-state conditions. Selection of MJF18004G requires circuit validation to confirm compatibility with elevated electrical ratings.

Frequently Asked Questions (FAQ)

Q: Can STL128D directly replace STL128DFP without circuit modification?

A: Yes. The STL128D maintains identical electrical specifications (4 A, 400 V, NPN) and through-hole mounting configuration. The package variant (TO-220 vs. TO-220FP) does not affect electrical performance or mechanical fit within standard TO-220 footprints. No circuit modification is required.

Q: What is the difference between TO-220 and TO-220FP packages?

A: Both are three-lead through-hole packages with identical electrical and thermal characteristics. TO-220FP denotes a full pack variant with additional mechanical features. Mechanical interchangeability is maintained for standard PCB applications.

Q: Is MJF18004G a direct replacement for STL128DFP?

A: MJF18004G is a similar substitute with enhanced electrical specifications. It exceeds STL128DFP ratings in collector current (5 A vs. 4 A), breakdown voltage (450 V vs. 400 V), and power dissipation (35 W vs. 30 W). Circuit validation is required to confirm compatibility with these elevated ratings. Vce saturation characteristics differ (750mV vs. 500mV), which may affect switching behavior in saturation-mode applications.

Q: Are all substitute parts RoHS and REACH compliant?

A: Yes. STL128D and MJF18004G both carry ROHS3 compliance and REACH unaffected status, matching the regulatory profile of the STL128DFP.

Q: Why is STL128DFP classified as obsolete?

A: Obsolete status indicates the manufacturer has discontinued production. The STL128D (active status) serves as the direct replacement, ensuring continued availability and supply chain support.

Q: Can MJF18004G be used in applications requiring exactly 4 A collector current?

A: Yes. MJF18004G is rated for 5 A maximum collector current, which encompasses 4 A operation. Circuit design must account for the higher current capability and ensure thermal management remains adequate. The device operates safely at or below 4 A.

Q: What are the key differences in DC current gain between these devices?

A: STL128DFP and STL128D specify hFE minimum of 10 @ 2A, 5V. MJF18004G specifies hFE minimum of 14 @ 300mA, 5V. The measurement conditions differ, reflecting different application profiles. Direct comparison requires evaluation at identical operating points.