ZTX558STOB Equivalent & Substitute Parts

Part Overview

The ZTX558STOB is a PNP bipolar junction transistor manufactured by Diodes Incorporated, designed for general-purpose switching and amplification applications. This device features a 400 V collector-emitter breakdown voltage rating, 200 mA maximum collector current, and 1 W power dissipation capability in a through-hole E-Line (TO-92 compatible) package.

The ZTX558STOB is classified as obsolete. Locating equivalent substitute parts is necessary to support ongoing production requirements, field repairs, and system maintenance where this component is specified in existing designs.

Substiute Parts

ZTX558STOB

Diodes IncorporatedIn Stock: 1018ZTX558STOB Datasheet

Current PartRFQ

ZTX558STZ

Diodes IncorporatedIn Stock: 10207ZTX558STZ Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the ZTX558STOB is determined by electrical and mechanical parameter equivalence. The following criteria establish valid substitution:

Electrical Parameters (Must Match):

• Transistor polarity: PNP
• Maximum collector current: 200 mA
• Collector-emitter breakdown voltage: 400 V
• Vce saturation characteristics: 500mV @ 6mA, 50mA
• Collector cutoff current: 100 nA
• DC current gain (hFE): minimum 100 @ 50mA, 10V
• Maximum power dissipation: 1 W
• Transition frequency: 50 MHz
• Operating temperature range: -55°C to 200°C

Mechanical Parameters (Must Match):

• Mounting type: Through Hole
• Package type: E-Line-3 with formed leads (TO-92 compatible)

Compliance Parameters (Must Match):

• RoHS3 compliance
• Moisture sensitivity level: 1 (Unlimited)

The ZTX558STZ qualifies as a direct substitute based on identical electrical specifications, mechanical compatibility, and regulatory compliance. The primary distinction is packaging format (Cut Tape versus the original specification) and product status (Active versus Obsolete).

Parameter Comparison

Engineering Selection Recommendations

The ZTX558STZ is a direct functional equivalent to the ZTX558STOB for all electrical and mechanical applications. Both devices share identical electrical specifications, thermal operating range, and package geometry.

Selection Basis:

The ZTX558STZ is recommended as the primary substitute due to its Active product status. The ZTX558STOB is classified as Obsolete, which creates supply chain risk and limits long-term availability. The ZTX558STZ maintains full compatibility with existing circuit designs while providing access to current manufacturing inventory.

Both parts maintain ROHS3 compliance and identical moisture sensitivity ratings, ensuring regulatory and environmental compatibility in production environments.

The packaging format difference (Cut Tape for ZTX558STZ versus the original specification) does not affect electrical performance or mechanical fit in through-hole applications. Both devices utilize the same E-Line-3 package with formed leads.

Frequently Asked Questions (FAQ)

Q: Can the ZTX558STZ be used as a direct replacement for the ZTX558STOB in existing circuit designs?

A: Yes. The ZTX558STZ is electrically and mechanically equivalent to the ZTX558STOB. All electrical parameters, including collector current, breakdown voltage, saturation characteristics, current gain, and frequency response, are identical. The through-hole E-Line-3 package geometry is the same, enabling direct substitution in PCB layouts without modification.

Q: What is the primary difference between the ZTX558STOB and ZTX558STZ?

A: The primary differences are product status and packaging format. The ZTX558STOB is classified as Obsolete, while the ZTX558STZ is Active. The ZTX558STZ is supplied in Cut Tape packaging, whereas the original part specification does not specify a particular tape format. Both devices are functionally identical in electrical performance and mechanical compatibility.

Q: Are there any compliance or regulatory differences between these parts?

A: No. Both the ZTX558STOB and ZTX558STZ are ROHS3 compliant and carry identical moisture sensitivity ratings (MSL 1 - Unlimited). Both parts are REACH Unaffected and classified under the same ECCN and HTSUS codes.

Q: What is the operating temperature range for these transistors?

A: Both devices operate across a junction temperature range of -55°C to 200°C (TJ), providing compatibility with industrial and high-temperature applications.

Q: Is the E-Line-3 package compatible with standard through-hole PCB assembly processes?

A: Yes. The E-Line-3 package with formed leads is a through-hole component compatible with standard PCB assembly equipment and processes. The package geometry is consistent between the ZTX558STOB and ZTX558STZ.

Q: What is the maximum power dissipation for this transistor?

A: The maximum power dissipation is 1 W for both the ZTX558STOB and ZTX558STZ. Circuit design must ensure that power dissipation does not exceed this rating under any operating condition.

Q: What is the minimum DC current gain (hFE) specification?

A: The minimum DC current gain is 100, measured at a collector current of 50 mA and collector-emitter voltage of 10 V. This specification applies to both the ZTX558STOB and ZTX558STZ.