2N4403_D29Z Equivalent & Substitute Parts

Part Overview

The 2N4403_D29Z is a PNP bipolar junction transistor manufactured by onsemi, rated for 40 V collector-emitter breakdown voltage and 600 mA maximum collector current. This device is packaged in TO-92-3 (TO-226AA) through-hole configuration and operates across a temperature range of -55°C to 150°C. The part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement continuity.

Key Parameters

Parameter	Value	Unit
Transistor Type	PNP	—
Voltage - Collector Emitter Breakdown (Max)	40	V
Current - Collector (Ic) (Max)	600	mA
Vce Saturation (Max) @ Ib, Ic	750 mV @ 50 mA, 500 mA	—
DC Current Gain (hFE) (Min) @ Ic, Vce	100 @ 150 mA, 2 V	—
Power - Max	625	mW
Frequency - Transition	200	MHz
Operating Temperature	-55 to 150	°C
Mounting Type	Through Hole	—
Package / Case	TO-226-3, TO-92-3 (TO-226AA) Formed Leads	—

Substitute Part Grouping Explanation

Substitute parts for the 2N4403_D29Z are classified into two categories based on electrical and mechanical parameter alignment:

Direct Substitutes (Identical Electrical Specifications): Parts that maintain all critical electrical parameters: 40 V collector-emitter breakdown voltage, 600 mA maximum collector current, 625 mW power dissipation, 200 MHz transition frequency, 100 minimum DC current gain, and identical saturation voltage characteristics. These parts are pin-compatible and functionally interchangeable in the TO-92-3 package. Direct substitutes include 2N4403TA and 2N4403TF from onsemi, and 2N4403BU from Fairchild Semiconductor.

Similar Substitutes (Comparable Electrical Specifications with Deviations): Parts that share the same transistor type (PNP), package family (TO-92 compatible), and core voltage rating but may differ in current handling, power dissipation, or frequency response. The 2N4403-AP from Micro Commercial Co and ZTX549STZ from Diodes Incorporated fall into this category. These parts require circuit-level evaluation to confirm suitability.

Substitution eligibility is determined by:

Transistor polarity (PNP)
Collector-emitter breakdown voltage rating (40 V minimum)
Collector current capability (600 mA minimum)
DC current gain (100 minimum at specified conditions)
Through-hole mounting compatibility
Operating temperature range overlap (-55°C to 150°C minimum)

Parameter Comparison

Part Number	Manufacturer	Product Status	Ic (Max) [mA]	Vce Breakdown (Max) [V]	Power (Max) [mW]	Frequency [MHz]	hFE (Min)	Package	Packaging Type
2N4403_D29Z	onsemi	Obsolete	600	40	625	200	100	TO-92-3	—
2N4403TA	onsemi	Active	600	40	625	200	100	TO-92-3	Cut Tape (CT)
2N4403TF	onsemi	Active	600	40	625	200	100	TO-92-3	Cut Tape (CT)
2N4403BU	Fairchild Semiconductor	Active	600	40	625	200	100	TO-92-3	Bulk
2N4403-AP	Micro Commercial Co	Obsolete	600	40	600	200	100	TO-92-3	Cut Tape (CT)
ZTX549STZ	Diodes Incorporated	Active	1000	30	1000	100	100	E-Line (TO-92 compatible)	Cut Tape (CT)

Engineering Selection Recommendations

Primary Substitutes (Recommended for Direct Replacement):

2N4403TA and 2N4403TF from onsemi are the preferred substitutes for the obsolete 2N4403_D29Z. Both parts are active products with identical electrical specifications, matching collector current, voltage rating, power dissipation, and frequency response. Both are ROHS3 compliant and carry REACH Unaffected status. The distinction between these parts is packaging format: 2N4403TA and 2N4403TF are supplied in cut tape, whereas the original part was supplied in an unspecified format. Inventory availability is substantial for both parts (60,100 and 1,500 units respectively).

2N4403BU from Fairchild Semiconductor is an active alternative with identical electrical parameters. This part is supplied in bulk packaging and maintains full compatibility with the original specification. Inventory availability is high at 69,662 units.

Secondary Substitutes (Conditional Replacement):

2N4403-AP from Micro Commercial Co shares the same base part number and electrical characteristics but is classified as obsolete. This part is suitable only when active alternatives are unavailable and existing inventory is accessible. Power dissipation is marginally lower at 600 mW versus 625 mW.

Limited Compatibility Substitute:

ZTX549STZ from Diodes Incorporated is a TO-92 compatible device with different electrical specifications. The collector-emitter breakdown voltage is reduced to 30 V, and the transition frequency is reduced to 100 MHz. However, this part offers higher collector current (1 A) and power dissipation (1 W). This part is suitable only for applications where the lower voltage rating and reduced frequency response are acceptable and where the higher current capability provides design margin.

Frequently Asked Questions (FAQ)

Q: Can 2N4403TA and 2N4403TF be used interchangeably with 2N4403_D29Z?

A: Yes. Both parts are onsemi products with identical electrical specifications, including 40 V breakdown voltage, 600 mA collector current, 625 mW power rating, and 200 MHz transition frequency. Pin configuration and package dimensions are identical. The only difference is packaging format (cut tape versus the original format).

Q: What is the difference between 2N4403TA and 2N4403TF?

A: Both parts are electrically identical with matching specifications. The designation suffix indicates different manufacturing or packaging batches from onsemi. Both are active products and suitable for direct substitution.

Q: Is 2N4403BU from Fairchild Semiconductor a direct replacement?

A: Yes. The 2N4403BU maintains all electrical specifications of the original part: 40 V breakdown voltage, 600 mA collector current, 625 mW power dissipation, and 200 MHz transition frequency. The part is supplied in bulk packaging rather than cut tape. Pin configuration and package dimensions are identical.

Q: Can ZTX549STZ replace the 2N4403_D29Z?

A: ZTX549STZ is not a direct replacement. While both are PNP transistors in TO-92 compatible packages, the ZTX549STZ has a lower collector-emitter breakdown voltage (30 V versus 40 V) and reduced transition frequency (100 MHz versus 200 MHz). This part is suitable only for applications where these reduced ratings are acceptable and where the higher current capability (1 A) and power dissipation (1 W) provide design benefit.

Q: Why is the 2N4403_D29Z classified as obsolete?

A: The original part is no longer in active production. However, multiple active alternatives with identical specifications are available from onsemi and other manufacturers, ensuring design continuity and procurement availability.

Q: What packaging formats are available for substitute parts?

A: Active substitutes are available in cut tape (2N4403TA, 2N4403TF) and bulk (2N4403BU) packaging. All maintain the same TO-92-3 through-hole package configuration. Packaging selection depends on procurement volume and assembly requirements.

Q: Are all substitute parts RoHS compliant?

A: The active direct substitutes (2N4403TA, 2N4403TF, 2N4403BU) are ROHS3 compliant. The 2N4403-AP is also ROHS3 compliant but is obsolete. ZTX549STZ is ROHS3 compliant and active.

Q: What is the operating temperature range for substitute parts?

A: All direct substitutes (2N4403TA, 2N4403TF, 2N4403BU, 2N4403-AP) operate from -55°C to 150°C, matching the original part. ZTX549STZ has an extended upper temperature limit of 200°C.

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