2N3904_D28Z Equivalent & Substitute Parts

Part Overview

The 2N3904_D28Z is a Bipolar (BJT) NPN transistor manufactured by onsemi, rated for 40 V collector-emitter breakdown voltage and 200 mA maximum collector current. This device is packaged in TO-92-3 through-hole configuration and is classified as Obsolete. The obsolete status necessitates identification of equivalent and substitute parts for ongoing design support and component procurement.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Current - Collector (Ic) Max	200	mA
Voltage - Collector Emitter Breakdown (Max)	40	V
Vce Saturation (Max) @ Ib, Ic	300 mV @ 5 mA, 50 mA	—
DC Current Gain (hFE) Min @ Ic, Vce	100 @ 10 mA, 1 V	—
Power - Max	625	mW
Frequency - Transition	300	MHz
Operating Temperature	-55 to 150	°C (TJ)
Mounting Type	Through Hole	—
Package / Case	TO-226-3, TO-92-3 (TO-226AA) Formed Leads	—

Substitute Part Grouping Explanation

Substitution eligibility for the 2N3904_D28Z is determined by the following critical parameters:

Electrical Parameters (Must Match):

Transistor Type: NPN
Current - Collector (Ic) Max: 200 mA
Voltage - Collector Emitter Breakdown (Max): 40 V
DC Current Gain (hFE) Min @ Ic, Vce: 100 @ 10 mA, 1 V
Operating Temperature Range: -55°C to 150°C (TJ)

Mechanical Parameters (Must Match):

Mounting Type: Through Hole
Package / Case: TO-92-3 (TO-226AA) Formed Leads

Acceptable Variations:

Vce Saturation (Max): 300 mV to 400 mV @ 5 mA, 50 mA
Frequency - Transition: 250 MHz to 300 MHz
Power - Max: 625 mW to 1.5 W
Packaging Format: Tape & Reel (TR) or Cut Tape (CT)
Product Status: Active or Obsolete
RoHS Compliance: ROHS3 Compliant acceptable

Substitute parts are grouped into two categories: Direct Manufacturer Equivalents (onsemi 2N3904 variants) and Similar Alternative (Parallax Inc. 500-00001).

Parameter Comparison

Part Number	Manufacturer	Ic (Max) mA	Vce Breakdown (Max) V	Vce Sat (Max) mV	hFE (Min)	Power (Max) mW	Frequency (Max) MHz	Packaging	Product Status
2N3904_D28Z	onsemi	200	40	300	100	625	300	TR	Obsolete
2N3904TA	onsemi	200	40	300	100	625	300	CT	Active
2N3904TAR	onsemi	200	40	300	100	625	300	CT	Active
2N3904TF	onsemi	200	40	300	100	625	300	CT	Active
2N3904TFR	onsemi	200	40	300	100	625	300	CT	Active
2N3904-AP	Micro Commercial Co	200	40	400	100	625	250	CT	Obsolete
500-00001	Parallax Inc.	200	40	300	100	1500	300	—	Active

Engineering Selection Recommendations

Primary Substitutes (onsemi 2N3904 Series):

The onsemi 2N3904TA, 2N3904TAR, 2N3904TF, and 2N3904TFR are direct electrical and mechanical equivalents to the 2N3904_D28Z. All four parts maintain identical electrical specifications and TO-92-3 package configuration. The primary distinction is packaging format: the original part is supplied in Tape & Reel (TR) format, while substitutes are available in Cut Tape (CT) format. All substitute variants carry Active product status and ROHS3 compliance, providing superior long-term availability compared to the Obsolete 2N3904_D28Z.

Secondary Substitute (Micro Commercial Co 2N3904-AP):

The 2N3904-AP from Micro Commercial Co meets all critical electrical parameters with minor variations: Vce Saturation is 400 mV (versus 300 mV) and Frequency - Transition is 250 MHz (versus 300 MHz). Both variations remain within acceptable operating margins for standard NPN switching applications. However, this part carries Obsolete product status, limiting its suitability for new procurement.

Alternative Option (Parallax Inc. 500-00001):

The Parallax Inc. 500-00001 provides identical electrical performance with enhanced power dissipation capability (1.5 W versus 625 mW). This part is suitable for applications requiring higher thermal headroom. Active product status ensures availability. Packaging information is not specified in the provided data.

Recommendation Priority:

onsemi 2N3904TA, 2N3904TAR, 2N3904TF, or 2N3904TFR (Active status, identical specifications)
Parallax Inc. 500-00001 (Active status, higher power rating)
Micro Commercial Co 2N3904-AP (Obsolete status, minor parameter variations)

Frequently Asked Questions (FAQ)

Q: Can I directly replace 2N3904_D28Z with 2N3904TA in my circuit?

A: Yes. The 2N3904TA is electrically and mechanically identical to the 2N3904_D28Z. Both devices share the same TO-92-3 package, identical electrical ratings (40 V, 200 mA, 300 MHz), and equivalent DC current gain specifications. The only difference is packaging format (Cut Tape versus Tape & Reel).

Q: What is the difference between 2N3904TA, 2N3904TAR, 2N3904TF, and 2N3904TFR?

A: All four onsemi variants are electrically identical and share the same TO-92-3 package. The suffix designations (TA, TAR, TF, TFR) indicate different packaging and tape configurations within the Cut Tape (CT) format. Selection among these variants depends on your procurement and assembly equipment compatibility.

Q: Why is the 2N3904_D28Z marked as Obsolete?

A: The 2N3904_D28Z carries Obsolete product status, indicating onsemi has discontinued active production and support. Active equivalent variants (2N3904TA, 2N3904TAR, 2N3904TF, 2N3904TFR) are available from the same manufacturer and are recommended for new designs and ongoing procurement.

Q: Can I use the Parallax Inc. 500-00001 as a substitute?

A: Yes, with consideration for the higher power rating. The Parallax 500-00001 meets all critical electrical parameters and maintains the TO-92 through-hole package. The increased power dissipation capability (1.5 W versus 625 mW) makes this part suitable for applications with higher thermal requirements. Verify package compatibility with your PCB layout, as specific package variant details are not provided.

Q: What are the key parameters I must verify when substituting this transistor?

A: Verify the following parameters match your circuit requirements: Collector-Emitter Breakdown Voltage (40 V), Maximum Collector Current (200 mA), DC Current Gain minimum (100 @ 10 mA, 1 V), and Operating Temperature Range (-55°C to 150°C). Confirm the TO-92-3 through-hole package is compatible with your PCB design. For applications sensitive to saturation voltage or transition frequency, confirm the specific variant meets your performance margins.

Q: Is the 2N3904-AP from Micro Commercial Co a suitable replacement?

A: The 2N3904-AP meets all critical electrical parameters with acceptable variations: Vce Saturation of 400 mV (versus 300 mV) and Frequency - Transition of 250 MHz (versus 300 MHz). These variations are within acceptable operating margins for standard switching applications. However, this part carries Obsolete product status. For new designs, onsemi Active variants are preferred.

Q: What compliance certifications should I verify for my application?

A: All substitute parts listed carry REACH Unaffected status and ROHS3 compliance. Verify these certifications align with your end-product regulatory requirements. The ECCN classification (EAR99) and HTSUS codes are consistent across all variants.

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