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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

STMicroelectronics TIP31A

Name: TIP31A
Brand: STMicroelectronics
SKU: TIP31A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TIP31A

Manufacturer:: STMicroelectronics

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: TIP31A.pdf

Description:: TRANS NPN 60V 3A TO-220

Quantity:: RFQ Add To RFQ list

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Inventory:2,083

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Product details

Overview

TIP31A from STMicroelectronics is an NPN silicon power transistor in TO-220 package, designed for linear amplification and switching applications. It features V_CEO = 60 V, I_C = 3 A, h_FE = 25–50 (at I_C = 1 A), V_CE(sat) = 1.2 V (at I_C = 3 A, I_B = 375 mA), and T_J(max) = 150 °C - enabling use in audio output stages and DC motor drivers.

For engineers reviewing the TIP31A datasheet, TIP31A pinout, TIP31A application, or TIP31A equivalent, key selection criteria include safe operating area (SOA) compliance at 25 °C case temperature, base-island process linearity, ECOPACK® lead-free packaging, and compatibility with complementary PNP TIP32A in push-pull configurations.

Technical Context

The TIP31A employs base-island epitaxial construction to improve h_FE linearity across collector current range and enhance switching speed versus legacy TIP31 devices. Its SOA is defined up to 300 ms pulse width with ≥1.5% duty cycle, supporting transient load handling in industrial power stages.

It operates with V_BE(on) = 1.8 V at I_C = 3 A and V_CE = 4 V, and exhibits low leakage: I_CEO ≤ 0.3 mA at V_CE = 30 V, I_CB0 ≤ 0.2 mA at V_CB = 60 V - critical for stable biasing in Class-AB amplifier designs.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	60 V - maximum collector-emitter voltage before breakdown under open-base condition; defines rail voltage limit in switching regulators.
I_C	3 A continuous - rated collector current at T_case = 25 °C; sets thermal design baseline for heatsink sizing.
h_FE	25–50 at I_C = 1 A - DC current gain range enabling predictable base drive calculation for linear operation.
V_CE(sat)	1.2 V at I_C = 3 A / I_B = 375 mA - saturation voltage determining conduction loss and junction temperature rise.
P_TOT	40 W at T_case = 25 °C - total power dissipation limit defining maximum allowable steady-state thermal load.
T_J(max)	150 °C - absolute maximum junction temperature; constrains derating curves and thermal interface material selection.

Pinout & Package

TO-220 package: three-terminal plastic housing with metal tab (collector) electrically connected to Pin 2; standardized mounting hole spacing (L1 = 3.50–3.93 mm) and lead pitch (e1 = 4.95–5.15 mm).

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Emission terminal	Low-impedance current exit path; referenced to ground in common-emitter configurations.
2 (Collector)	Current collection node	Internally bonded to metal tab; requires electrical isolation when mounted to heatsink.
3 (Base)	Control input	Current-driven gate; requires series resistor to limit I_B ≤ 1 A per absolute rating.

Key Features

Feature	Design Value
Enhanced h_FE linearity	Improved β consistency across 100 mA–3 A range reduces distortion in audio output stages.
High switching speed	Short storage time enables >100 kHz PWM operation in DC-DC converters without excessive turn-off loss.
Base-island technology	Epitaxial base structure lowers base resistance and improves thermal stability of gain.
ECOPACK® lead-free	RoHS-compliant second-level interconnect with JEDEC JESD97 marking; supports automated reflow assembly.

Applications

Audio Power Amplifier

DC Motor Driver

Use Scenario: Output stage in 10–20 W Class-AB audio amplifiers driving 4–8 Ω speakers.

IC Role / Device Role / Timing Role: NPN power switch delivering peak current up to 3 A into reactive load.

Use Value: V_CE(sat) ≤ 1.2 V minimizes heat generation; h_FE linearity preserves low THD below 1% at full output.

Use Scenario: H-bridge half-bridge leg controlling bidirectional 12–24 V DC motors in industrial actuators.

IC Role / Device Role / Timing Role: High-current switching element toggled by microcontroller GPIO via base resistor network.

Use Value: I_CM = 5 A peak handles motor stall current; SOA curve validated for 300 ms pulses ensures reliability during startup surge.

Linear Voltage Regulator

Switching Power Supply

Use Scenario: Pass transistor in adjustable 3–15 V, 2 A linear regulators using LM317 feedback loop.

IC Role / Device Role / Timing Role: Series pass element dissipating variable power based on input-output differential.

Use Value: P_TOT = 40 W at T_case = 25 °C allows stable operation with modest heatsinking at 12 V dropout.

Use Scenario: Main switch in 50–100 W flyback or forward converter operating at 50–100 kHz.

IC Role / Device Role / Timing Role: Primary-side switching transistor gated by UC384x controller.

Use Value: Fast switching speed and low storage time reduce switching losses; V_CEO = 60 V supports 48 V input designs with margin.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN power transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJD31C	TO-252 (DPAK) surface-mount package; same V_CEO/I_C, but h_FE min = 10 at I_C = 3 A.	Requires PCB layout revision; unsuitable for through-hole prototyping or heatsink bolt-down.	Select when automated SMT assembly and space-constrained layouts are prioritized over mechanical serviceability.
TIP31C	Higher V_CEO = 100 V; otherwise identical pinout, package, and gain specs.	Enables use in 72 V battery systems or higher-voltage industrial supplies where 60 V margin is insufficient.	Choose when system rail voltage exceeds 45 V and long-term SOA robustness at elevated V_CE is required.

Compared with MJD31C and TIP31C, the TIP31A offers optimal balance of through-hole serviceability, proven thermal performance in TO-220, and sufficient voltage headroom for 24–48 V industrial systems - making it preferred for development, repair, and medium-volume production where mechanical robustness and thermal testability matter.

Availability

TIP31A is available at Aetrix Electronics and suitable for audio amplifiers, DC motor controllers, linear voltage regulators, and switching power supplies requiring stable component supply and long-lifecycle support.

Supply support for TIP31A includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing analog, power, MCU, and sensor solutions for industrial, automotive, and consumer markets.

The TIP31A belongs to ST's legacy power bipolar transistor family, engineered specifically for cost-sensitive, thermally demanding linear and switching applications where ruggedness and manufacturability outweigh ultra-high-frequency requirements.

FAQ

Is the TIP31A pinout compatible with the TIP32A?

Yes - both share identical TO-220 pinout (Emitter-Collector-Base), enabling direct complementary pairing in push-pull or quasi-complementary amplifier outputs. The TIP32A is its PNP counterpart with matching voltage/current ratings and thermal characteristics.

What is the recommended base resistor value for switching a 2 A load?

With h_FE ≥ 25 at I_C = 2 A, minimum I_B = 80 mA is required. Using a 5 V logic drive, R_B = (5 V − V_BE(on)) / 80 mA ≈ 39 Ω (standard value), ensuring saturation while limiting I_B below 1 A absolute max.

Does the TIP31A require a heatsink in linear regulator applications?

Yes - at 2 A output with 10 V dropout, power dissipation reaches 20 W. Since P_TOT = 40 W only applies at T_case = 25 °C, a heatsink maintaining T_case ≤ 60 °C is mandatory to stay within SOA limits and avoid thermal runaway.

Can the TIP31A be used in avalanche mode?

No - the device is not rated or characterized for controlled avalanche operation. Its V_CEO(sus) = 60 V is specified only under pulsed conditions with I_C = 30 mA; exceeding this risks secondary breakdown and permanent damage without external clamping.

TIP31A Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Active

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 3 A

Voltage - Collector Emitter Breakdown (Max):: 60 V

Vce Saturation (Max) @ Ib, Ic:: 1.2V @ 375mA, 3A

Current - Collector Cutoff (Max):: 300µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 10 @ 3A, 4V

Power - Max:: 2 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220

TIP31A FAQ

1.How can I place an order for TIP31A through Aetrix?

Please submit a Request for Quotation (RFQ) for TIP31A on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for TIP31A reliable?

The price and inventory of TIP31A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TIP31A is usually 5 days.

3.What payment methods are accepted for TIP31A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TIP31A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TIP31A?

TIP31A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TIP31A order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for TIP31A?

For technical support, including TIP31A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TIP31A requirements.

6.How does Aetrix verify that TIP31A is sourced from the original manufacturer or authorized distributors?

All TIP31A products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that TIP31A meets industry standards.

7.What is the process for return or replacement of TIP31A?

All TIP31A units undergo pre-shipment inspection (PSI). If there is an issue with TIP31A, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The TIP31A part is unused and in its original packaging.

Return procedure for TIP31A:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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