ZTX449STOB Equivalent & Substitute Parts

Part Overview

The ZTX449STOB is an NPN bipolar junction transistor manufactured by Diodes Incorporated, designed for general-purpose switching and amplification applications. This device features a maximum collector current of 1 A, collector-emitter breakdown voltage of 30 V, and maximum power dissipation of 1 W in a through-hole E-Line (TO-92 compatible) package.

The ZTX449STOB is classified as obsolete. Locating equivalent substitute parts is necessary to maintain design continuity, ensure component availability for production, and support long-term product maintenance and repair operations.

Substiute Parts

ZTX449STOB

Diodes IncorporatedIn Stock: 819ZTX449STOB Datasheet

Current PartRFQ

KSD471ACYTA

Fairchild SemiconductorIn Stock: 6008KSD471ACYTA Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the ZTX449STOB is determined by electrical and mechanical parameter compatibility within the NPN bipolar junction transistor category. The following parameters establish substitution eligibility:

Electrical Parameters (Critical):

• Transistor polarity: NPN
• Maximum collector current: 1 A or greater
• Collector-emitter breakdown voltage: 30 V or greater
• Maximum power dissipation: 800 mW or greater
• Collector cutoff current: 100 nA or less

Mechanical Parameters (Critical):

• Mounting type: Through Hole
• Package compatibility: TO-92-3 or E-Line-3 formed leads

The KSD471ACYTA meets all electrical and mechanical substitution criteria. Both devices operate within the same voltage and current ratings, feature compatible through-hole packaging, and maintain equivalent DC current gain characteristics suitable for the same application classes.

Parameter Comparison

Engineering Selection Recommendations

The KSD471ACYTA is an active-status substitute for the obsolete ZTX449STOB. Both devices share identical electrical ratings for collector current (1 A maximum) and collector-emitter breakdown voltage (30 V maximum), with compatible through-hole TO-92-3 packaging.

The KSD471ACYTA offers superior component availability, as it is currently in active production status with 5946 units in stock, compared to the ZTX449STOB's obsolete status. Both devices comply with RoHS3 and REACH regulations, ensuring environmental and regulatory compatibility.

The KSD471ACYTA exhibits a maximum power dissipation of 800 mW compared to the ZTX449STOB's 1 W rating. Applications requiring sustained power dissipation approaching 1 W must verify thermal management compatibility with the substitute device. The transition frequency of the KSD471ACYTA (130 MHz) is lower than the ZTX449STOB (150 MHz); applications operating at frequencies approaching 150 MHz require performance validation.

Frequently Asked Questions (FAQ)

Q: Can the KSD471ACYTA directly replace the ZTX449STOB in existing designs?

A: The KSD471ACYTA is electrically compatible for applications within the specified collector current (1 A maximum) and voltage (30 V maximum) ratings. Physical package compatibility exists for through-hole PCB layouts designed for TO-92-3 or E-Line-3 formed leads. Thermal design verification is required for applications approaching 1 W power dissipation, as the substitute device is rated at 800 mW maximum.

Q: What are the key differences between these two devices?

A: The primary differences are product status (KSD471ACYTA is active; ZTX449STOB is obsolete), maximum power dissipation (800 mW versus 1 W), transition frequency (130 MHz versus 150 MHz), and maximum operating temperature (150°C versus 200°C). Electrical ratings for collector current and breakdown voltage are identical.

Q: Are there package compatibility concerns?

A: Both devices use through-hole formed leads in TO-92-3 compatible packages. Physical pin configuration and spacing are compatible with standard TO-92-3 PCB footprints. No package modification is required for mechanical substitution.

Q: What compliance certifications apply to the substitute part?

A: The KSD471ACYTA complies with RoHS3 and maintains EAR99 export classification. REACH status is unaffected. These certifications match the regulatory requirements of the original ZTX449STOB device.

Q: Should I test the substitute part before production implementation?

A: Verification of thermal performance and frequency response characteristics is appropriate for applications operating at the upper limits of the specified electrical ratings. Standard component qualification procedures apply.