TIP31B Equivalent & Substitute Parts

Part Overview

The TIP31B is an NPN bipolar junction transistor manufactured by onsemi, rated for 80 V collector-emitter breakdown voltage and 3 A maximum collector current in a TO-220-3 through-hole package. This device is classified as obsolete, necessitating identification of equivalent and substitute components for ongoing design requirements and production continuity. The TIP31B serves in applications requiring medium-voltage, medium-current switching and amplification functions with a 2 W power dissipation capability.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Current - Collector (Ic) Max	3	A
Voltage - Collector Emitter Breakdown (Max)	80	V
Vce Saturation (Max) @ Ib, Ic	1.2 @ 375mA, 3A	V
Current - Collector Cutoff (Max)	300	µA
DC Current Gain (hFE) Min @ Ic, Vce	10 @ 3A, 4V	—
Power - Max	2	W
Frequency - Transition	3	MHz
Mounting Type	Through Hole	—
Package / Case	TO-220-3	—
Operating Temperature (TJ)	150	°C

Substitute Part Grouping Explanation

Substitution of the TIP31B is determined by electrical and mechanical compatibility across the following critical parameters:

Electrical Compatibility Criteria:

Transistor type must be NPN
Maximum collector current (Ic) must equal or exceed 3 A
Collector-emitter breakdown voltage (Vce) must equal or exceed 80 V
Vce saturation characteristics must be compatible at specified base and collector currents
DC current gain (hFE) must meet or exceed 10 @ 3A, 4V
Transition frequency must equal or exceed 3 MHz

Mechanical Compatibility Criteria:

Mounting type must be through-hole
Package must be TO-220-3 or equivalent TO-220 footprint

Substitution Categories:

Direct Equivalent: TIP31BG meets all electrical parameters identically to TIP31B with identical Vce saturation, collector cutoff current, and DC current gain. The primary difference is product status (active versus obsolete) and packaging format (tube versus unspecified). This part provides direct functional replacement.

Functional Equivalent with Higher Voltage Rating: TIP31C exceeds the voltage specification (100 V versus 80 V) while maintaining identical collector current, saturation voltage, and transition frequency. The power dissipation rating is significantly higher (40 W versus 2 W), and collector cutoff current is lower (200 µA versus 300 µA). This part is suitable for applications where higher voltage headroom is beneficial.

Functional Equivalent with Lower Voltage Rating: TIP31G operates at reduced collector-emitter breakdown voltage (40 V versus 80 V) while maintaining identical collector current, saturation voltage, DC current gain, and transition frequency. This part is suitable only for applications where the 40 V rating is sufficient.

Parameter Comparison

Parameter	TIP31B (Main)	TIP31BG (Direct)	TIP31C (Higher Voltage)	TIP31G (Lower Voltage)
Manufacturer	onsemi	onsemi	Fairchild Semiconductor	onsemi
Product Status	Obsolete	Active	Active	Last Time Buy
Transistor Type	NPN	NPN	NPN	NPN
Current - Collector (Ic) Max	3 A	3 A	3 A	3 A
Voltage - Collector Emitter Breakdown (Max)	80 V	80 V	100 V	40 V
Vce Saturation (Max) @ Ib, Ic	1.2V @ 375mA, 3A	1.2V @ 375mA, 3A	1.2V @ 375mA, 3A	1.2V @ 375mA, 3A
Current - Collector Cutoff (Max)	300 µA	300 µA	200 µA	300 µA
DC Current Gain (hFE) Min @ Ic, Vce	10 @ 3A, 4V	10 @ 3A, 4V	10 @ 3A, 4V	10 @ 3A, 4V
Power - Max	2 W	2 W	40 W	2 W
Frequency - Transition	3 MHz	3 MHz	3 MHz	3 MHz
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	TO-220-3	TO-220-3	TO-220-3	TO-220-3
Operating Temperature (TJ)	150°C	-65°C ~ 150°C	Not specified	-65°C ~ 150°C
RoHS Status	Not specified	ROHS3 Compliant	Not specified	ROHS3 Compliant

Engineering Selection Recommendations

TIP31BG (Direct Equivalent - Recommended Primary Substitute)

TIP31BG is the optimal substitute for TIP31B applications. This part maintains identical electrical specifications across all critical parameters: 80 V collector-emitter breakdown voltage, 3 A maximum collector current, 1.2 V saturation voltage, 10 hFE minimum, and 3 MHz transition frequency. TIP31BG is manufactured by onsemi, the original TIP31B manufacturer, ensuring design continuity. The part holds active product status with 2000 units in stock, providing supply security. TIP31BG is ROHS3 compliant and carries an extended operating temperature range (-65°C to 150°C) compared to the TIP31B specification. The TO-220-3 package footprint is identical, requiring no PCB modifications.

TIP31C (Higher Voltage Alternative)

TIP31C is suitable for applications where increased voltage margin is required or beneficial. This part provides 100 V collector-emitter breakdown voltage, exceeding the TIP31B specification by 20 V. All other electrical parameters remain compatible: 3 A collector current, 1.2 V saturation voltage, and 3 MHz transition frequency. TIP31C offers significantly higher power dissipation capability (40 W versus 2 W), enabling use in higher-power applications. The part is manufactured by Fairchild Semiconductor and maintains active product status with 69,348 units in stock. TIP31C is suitable only when the higher voltage rating does not create design conflicts and when the increased power capability is either required or acceptable.

TIP31G (Lower Voltage Alternative)

TIP31G is applicable only to applications where the 40 V collector-emitter breakdown voltage is sufficient for circuit requirements. This part maintains identical collector current (3 A), saturation voltage (1.2 V), DC current gain (10 hFE), and transition frequency (3 MHz) specifications. TIP31G is manufactured by onsemi with last-time-buy product status and 1622 units in stock. The reduced voltage rating makes this part unsuitable for circuits designed around the TIP31B's 80 V specification. Selection of TIP31G requires explicit verification that circuit operating voltages remain below 40 V under all conditions.

Frequently Asked Questions (FAQ)

Q: Can TIP31BG be used as a direct replacement for TIP31B without circuit modifications?

A: Yes. TIP31BG maintains identical electrical specifications for collector current, collector-emitter breakdown voltage, saturation voltage, DC current gain, and transition frequency. The TO-220-3 package footprint is identical. No circuit modifications are required. TIP31BG is the recommended substitute.

Q: What is the primary difference between TIP31B and TIP31BG?

A: The primary differences are product status (TIP31B is obsolete; TIP31BG is active) and packaging format (TIP31B packaging unspecified; TIP31BG supplied in tube). Electrical specifications are identical. TIP31BG includes ROHS3 compliance and an extended operating temperature range specification.

Q: Can TIP31C replace TIP31B in all applications?

A: TIP31C is electrically compatible for applications where the 100 V collector-emitter breakdown voltage does not create design conflicts. The higher voltage rating and significantly higher power dissipation (40 W versus 2 W) make TIP31C suitable for higher-power applications. However, TIP31C is manufactured by Fairchild Semiconductor rather than onsemi. Verify that the higher power rating does not introduce thermal management changes or other design impacts.

Q: Is TIP31G a suitable substitute for TIP31B?

A: TIP31G is suitable only for applications where circuit operating voltages remain below 40 V under all conditions. The 40 V collector-emitter breakdown voltage is 50% lower than TIP31B's 80 V rating. All other electrical parameters are identical. TIP31G is not recommended as a general substitute without explicit circuit voltage verification.

Q: What is the significance of the TO-220-3 package specification?

A: The TO-220-3 package is a three-lead through-hole component with standardized pin spacing and mounting configuration. All substitute parts (TIP31BG, TIP31C, TIP31G) use the TO-220-3 package, ensuring identical PCB footprint compatibility. No board redesign is required when substituting between these parts.

Q: Are there compliance or regulatory differences between TIP31B and its substitutes?

A: TIP31BG and TIP31G are ROHS3 compliant. TIP31B and TIP31C compliance status is not specified in the provided data. All parts carry REACH Unaffected status and EAR99 ECCN classification. Verify compliance requirements for your specific application and regulatory jurisdiction.

Q: What inventory considerations should guide substitute selection?

A: TIP31BG (2000 units), TIP31C (69,348 units), and TIP31G (1622 units) are all in stock. TIP31BG and TIP31G are onsemi products with active or last-time-buy status. TIP31C is a Fairchild Semiconductor product with active status and the highest inventory level. For long-term supply security, TIP31C offers the largest available stock.

Q: Can TIP31B and its substitutes be used interchangeably on the same PCB assembly?

A: Yes, provided that circuit voltage requirements are met. TIP31BG is the direct equivalent requiring no circuit analysis. TIP31C requires verification that the higher voltage rating does not create design conflicts. TIP31G requires explicit confirmation that circuit voltages remain below 40 V. All parts use identical TO-220-3 footprints.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message