KA3842BD Equivalent & Substitute Parts

Part Overview

The KA3842BD is an offline switch IC manufactured by onsemi, designed for power management applications in DC-DC converter topologies. This 14-SOIC package device operates as a current-mode PWM controller supporting offline converter configurations with switching frequencies up to 500kHz. The product is classified as obsolete, making equivalent and substitute parts necessary for new designs, production continuity, and component sourcing.

Substiute Parts

KA3842BD

onsemiIn Stock: 3253KA3842BD Datasheet

Current PartRFQ

UC3842BDG

onsemiIn Stock: 4004UC3842BDG Datasheet

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UC3842BDR2G

onsemiIn Stock: 4243UC3842BDR2G Datasheet

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UC3842BVDR2G

onsemiIn Stock: 3672UC3842BVDR2G Datasheet

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TL3842BD

Texas InstrumentsIn Stock: 1565TL3842BD Datasheet

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TL3842BDR

Texas InstrumentsIn Stock: 3415TL3842BDR Datasheet

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TL3842DR

Texas InstrumentsIn Stock: 2738TL3842DR Datasheet

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UC3842AD

Fairchild SemiconductorIn Stock: 1000310UC3842AD Datasheet

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UC3842ADTR

Texas InstrumentsIn Stock: 5802UC3842ADTR Datasheet

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UC3842D

UnitrodeIn Stock: 5712UC3842D Datasheet

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UC3842DTR

Texas InstrumentsIn Stock: 3447UC3842DTR Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the KA3842BD is determined by the following critical parameters:

• Package compatibility: 14-SOIC form factor with 0.154" (3.90mm) width
• Supply voltage range: 10V ~ 30V operational window (encompasses KA3842BD 12V ~ 25V requirement)
• Switching frequency capability: Up to 500kHz
• Control architecture: Frequency control PWM functionality
• Mounting type: Surface mount configuration
• Operating temperature range: Minimum 0°C ~ 70°C support

Substitute parts must maintain electrical compatibility across these parameters while supporting equivalent DC-DC converter topologies (boost, flyback, forward configurations). All listed substitutes operate within the specified voltage and frequency ranges with identical package geometry and pin configuration.

Parameter Comparison

Engineering Selection Recommendations

For applications currently using the KA3842BD, the following substitution priorities apply based on product status and compliance:

Primary Recommendation: UC3842BDR2G (onsemi) or TL3842BDR (Texas Instruments) are preferred substitutes. Both devices maintain active product status, ensuring long-term availability and supply chain continuity. UC3842BDR2G extends the supply voltage range to 10V ~ 30V, providing broader operational flexibility. TL3842BDR offers equivalent electrical performance with ROHS3 compliance and active manufacturing status.

Extended Temperature Range Option: UC3842BVDR2G supports -40°C ~ 105°C operating temperature, suitable for applications requiring enhanced thermal performance beyond the standard 0°C ~ 70°C range. This device is packaged in cut tape format and maintains all core electrical parameters.

Alternative Sources: UC3842DTR (Texas Instruments) and UC3842ADTR (Texas Instruments) provide active product status with ROHS3 compliance. Both support the required 14-SOIC package and frequency control architecture.

End-of-Life Consideration: TL3842BD carries Last Time Buy status, indicating limited future availability. While electrically compatible, this part should not be selected for new long-term production designs.

All recommended substitutes maintain identical 14-SOIC package geometry, surface mount configuration, and frequency control functionality required for direct replacement in existing circuit designs.

Frequently Asked Questions (FAQ)

Q: Can UC3842BDR2G directly replace KA3842BD in existing designs?

A: Yes. Both devices share identical 14-SOIC package geometry, pin configuration, and frequency control architecture. UC3842BDR2G operates within a broader supply voltage range (10V ~ 30V) that encompasses the KA3842BD specification (12V ~ 25V), ensuring full electrical compatibility.

Q: What is the difference between UC3842BDG and UC3842BDR2G?

A: The primary difference is packaging format. UC3842BDG is supplied in tube packaging, while UC3842BDR2G uses tape and reel format. Both devices are electrically identical with identical 14-SOIC package dimensions. Selection depends on procurement and assembly requirements.

Q: Why does UC3842BVDR2G have a wider operating temperature range?

A: UC3842BVDR2G is rated for -40°C ~ 105°C operation compared to the standard 0°C ~ 70°C range. This extended specification accommodates applications in harsh thermal environments. All other electrical parameters remain equivalent to standard variants.

Q: Are Texas Instruments TL3842 variants compatible with onsemi UC3842 parts?

A: Yes. TL3842BD, TL3842BDR, and TL3842DR are functionally equivalent to UC3842 variants. Both manufacturers produce pin-compatible devices supporting identical topologies (boost, flyback, forward) with equivalent switching frequency and duty cycle specifications. Cross-manufacturer substitution is electrically valid.

Q: What does "Last Time Buy" status mean for TL3842BD?

A: Last Time Buy indicates the manufacturer has announced end-of-production. While currently available, this product will not be manufactured beyond a specified date. For new designs requiring long-term component availability, select active status alternatives such as TL3842BDR or UC3842BDR2G.

Q: Do all substitutes support the same 500kHz switching frequency?

A: All listed substitutes support up to 500kHz switching frequency. UC3842ADTR and UC3842DTR do not specify maximum switching frequency in provided data, but maintain functional equivalence through identical control architecture and package configuration.

Q: Is RoHS3 compliance required for substitution?

A: All active and recently obsolete substitute parts carry ROHS3 compliance certification. The original KA3842BD does not specify RoHS status. For applications requiring RoHS compliance, select from UC3842BDR2G, TL3842BDR, TL3842DR, UC3842ADTR, or UC3842DTR.