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

onsemi TIP122TU

Name: TIP122TU
Brand: onsemi
SKU: TIP122TU
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TIP122TU

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-220-3

Datasheet:: TIP122TU.pdf

Description:: TRANS NPN DARL 100V 5A TO-220-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

TIP122TU from onsemi is an NPN epitaxial Darlington transistor in TO-220 3L package, rated for 100 V V_CEO, 5 A DC collector current, and 65 W case power dissipation at 25°C. It delivers h_FE ≥ 1000 at IC = 3 A, V_CE = 3 V, with V_CE(sat) = 4.0 V at IC = 5 A/IB = 20 mA, used in medium-power linear and switching applications such as motor drivers and relay interfaces.

For engineers reviewing the TIP122TU datasheet, pinout, applications, or equivalent options, key selection criteria include its 100 V blocking capability, Darlington gain structure, TO-220 thermal performance, and rail-packaged availability for automated assembly.

Technical Context

The TIP122TU integrates two cascaded NPN transistors with internal base-emitter resistors (R1 ≈ 8 kΩ, R2 ≈ 0.12 kΩ) to achieve high DC current gain and simplified drive requirements. Its Darlington configuration enables low base drive current (IB ≤ 120 mA) to switch up to 5 A load current while maintaining defined saturation behavior.

Designed for operation at junction temperatures up to 150°C, the device exhibits ICEO ≤ 0.5 mA at V_CE = 50 V and ICBO ≤ 0.2 mA at V_CB = 100 V, supporting reliable performance in industrial control and power interface circuits where voltage margin and leakage stability are critical.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	100 V - Maximum continuous collector-emitter voltage before breakdown; supports 48 V and 72 V DC bus switching with safety margin.
I_C (DC)	5 A - Rated continuous collector current; defines maximum steady-state load handling capacity with adequate heatsinking.
P_C (T_C = 25°C)	65 W - Case power dissipation limit; determines thermal design basis when mounted on heatsink at 25°C ambient case temperature.
h_FE	≥1000 - Minimum DC current gain at IC = 3 A/VCE = 3 V; enables microcontroller GPIO-level base drive without external amplification.
V_CE(sat)	4.0 V @ IC = 5 A, IB = 20 mA - Saturation voltage under full-rated load; sets conduction loss and heat generation during on-state operation.
C_ob	200 pF @ V_CB = 10 V - Output capacitance affecting switching speed and EMI in PWM-driven loads like solenoids or DC motors.

Pinout & Package

Package: TO-220 3L (Single Gauge), through-hole, vertical mounting with metal tab electrically connected to collector. Requires mechanical isolation if collector is not at chassis ground.

Pin/Terminal	Circuit Role	Design Meaning
1 (Base)	Control input	Receives low-current drive signal; internal 8 kΩ resistor to emitter simplifies biasing and improves turn-off reliability.
2 (Collector)	High-current output node	Connected to metal tab; must be electrically isolated from heatsink unless circuit reference permits; handles full load current path.
3 (Emitter)	Current return path	Low-side switching reference; internal 0.12 kΩ resistor provides emitter degeneration for improved thermal stability and gain consistency.

Key Features

Feature	Design Value
Integrated Darlington pair	Eliminates need for external driver stage; reduces component count and PCB space in discrete power switch designs.
Internal base-emitter resistors	Enables clean turn-off without external pull-down; prevents latch-up in inductive load switching with flyback diodes.
100 V V_CEO rating	Supports direct interface with 72 V battery systems and industrial 48 V DC distribution without series voltage clamping.
TO-220 thermal performance	65 W case dissipation allows >3 A continuous current at 70°C ambient with standard 1.5°C/W heatsink, reducing thermal derating overhead.

Applications

DC Motor Control	Relay Driver Circuit
Use Scenario: Bidirectional 24–48 V brushed DC motor control in industrial actuators and HVAC dampers. IC Role / Device Role / Timing Role: Low-side NPN Darlington switch providing high-current commutation with TTL/CMOS-compatible base drive. Use Value: Delivers 5 A peak current per channel with <4.0 V saturation drop, minimizing I²R losses and enabling compact heatsink design.	Use Scenario: Driving 12–24 V coil relays in PLC I/O modules and building automation panels. IC Role / Device Role / Timing Role: High-gain switching element replacing discrete BJT pairs to reduce bill-of-materials and layout complexity. Use Value: h_FE ≥ 1000 ensures reliable activation with ≤10 mA MCU GPIO drive, eliminating need for base current limiting resistors in many cases.
Linear Regulator Pass Element	Lamp Dimming Interface
Use Scenario: Series pass transistor in adjustable 0–30 V, 3 A linear power supplies for test equipment and analog lab benches. IC Role / Device Role / Timing Role: Voltage-controlled current source operating in active region with stable h_FE and low V_BE(on) drift. Use Value: V_BE(on) = 2.5 V at IC = 3 A enables precise current mirror referencing and predictable thermal feedback loop behavior.	Use Scenario: Phase-angle dimming interface for incandescent and halogen lamps in residential lighting controls. IC Role / Device Role / Timing Role: AC mains-triggered switch using zero-crossing detection and snubberless triac drive staging. Use Value: 100 V V_CEO and 200 pF Cob support safe operation across 120/230 VAC RMS with minimal dv/dt-induced false triggering.

DC Motor Control

Relay Driver Circuit

Use Scenario: Bidirectional 24–48 V brushed DC motor control in industrial actuators and HVAC dampers.

IC Role / Device Role / Timing Role: Low-side NPN Darlington switch providing high-current commutation with TTL/CMOS-compatible base drive.

Use Value: Delivers 5 A peak current per channel with <4.0 V saturation drop, minimizing I²R losses and enabling compact heatsink design.

Use Scenario: Driving 12–24 V coil relays in PLC I/O modules and building automation panels.

IC Role / Device Role / Timing Role: High-gain switching element replacing discrete BJT pairs to reduce bill-of-materials and layout complexity.

Use Value: h_FE ≥ 1000 ensures reliable activation with ≤10 mA MCU GPIO drive, eliminating need for base current limiting resistors in many cases.

Linear Regulator Pass Element

Lamp Dimming Interface

Use Scenario: Series pass transistor in adjustable 0–30 V, 3 A linear power supplies for test equipment and analog lab benches.

IC Role / Device Role / Timing Role: Voltage-controlled current source operating in active region with stable h_FE and low V_BE(on) drift.

Use Value: V_BE(on) = 2.5 V at IC = 3 A enables precise current mirror referencing and predictable thermal feedback loop behavior.

Use Scenario: Phase-angle dimming interface for incandescent and halogen lamps in residential lighting controls.

IC Role / Device Role / Timing Role: AC mains-triggered switch using zero-crossing detection and snubberless triac drive staging.

Use Value: 100 V V_CEO and 200 pF Cob support safe operation across 120/230 VAC RMS with minimal dv/dt-induced false triggering.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BD679A	V_CEO = 80 V, I_C = 4 A, h_FE = 750 min, TO-126 package	Lower voltage rating and smaller package limit use in 72 V systems and high-power thermal management	Select BD679A only for space-constrained 48 V or lower applications where 65 W dissipation is not required.
TIP127TU	Complementary PNP Darlington, same package, V_CEO = 100 V, but requires inverted drive logic and negative supply reference	Used in high-side or complementary push-pull configurations, not direct replacement in low-side NPN roles	Choose TIP127TU only when designing symmetrical output stages or high-side switching with referenced emitter control.

Compared with BD679A and TIP127TU, the TIP122TU offers higher voltage margin and superior thermal handling in TO-220, making it optimal for standalone low-side switching in industrial 48–72 V DC systems where reliability and heatsink compatibility are prioritized over footprint size or complementary topology.

Availability

TIP122TU is available at Aetrix Electronics and suitable for DC motor control, relay driving, linear regulator pass elements, and lamp dimming interfaces requiring stable component supply and rail-packaged through-hole assembly.

Supply support for TIP122TU 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

onsemi (formerly ON Semiconductor) is a global semiconductor manufacturer specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The TIP122TU belongs to the legacy TIP12x Darlington transistor family designed specifically for cost-sensitive, medium-power linear and switching applications in industrial controls, power supplies, and electromechanical interfaces.

FAQ

What is the maximum continuous collector current for TIP122TU?

The TIP122TU is rated for 5 A DC collector current (I_C) at T_C = 25°C with appropriate heatsinking. This rating assumes proper thermal management; current must be derated linearly above 25°C case temperature per the 0.5 W/°C derating curve shown in Figure 5 of the datasheet. Exceeding this limit risks thermal runaway due to the Darlington's inherent gain and V_BE temperature coefficient.

Is TIP122TU pin-compatible with TIP120TU or TIP121TU?

Yes, TIP122TU shares identical TO-220 3L pinout (Base–Collector–Emitter) and mechanical footprint with TIP120TU and TIP121TU. However, voltage ratings differ: TIP122TU supports 100 V V_CEO, versus 60 V for TIP120TU and 80 V for TIP121TU. Substitution requires verification that system voltage stresses remain within the lower-rated device's absolute maximum limits.

Does TIP122TU require an external base resistor?

The TIP122TU includes an internal 8 kΩ base-to-emitter resistor, which aids turn-off but does not eliminate the need for an external series base resistor in most designs. An external resistor (typically 1–2.2 kΩ) is still required to limit base current during turn-on and prevent excessive IB beyond the 120 mA absolute maximum, especially when driven from 5 V logic sources.

What is the typical V_CE(sat) of TIP122TU at full load?

The TIP122TU specifies V_CE(sat) = 4.0 V maximum at I_C = 5 A and I_B = 20 mA. At lighter loads (e.g., I_C = 3 A), V_CE(sat) drops to 2.0 V max. This saturation voltage directly determines conduction loss (P = V_CE(sat) × I_C) and must be included in thermal calculations-e.g., 4.0 V × 5 A = 20 W dissipated solely in the TIP122TU under worst-case saturation.

Can TIP122TU be used in high-frequency PWM applications?

The TIP122TU is not optimized for high-frequency switching: its Cob = 200 pF and relatively slow storage time (typical t_s > 1 μs) limit practical use to PWM frequencies below 10 kHz. For 20+ kHz motor control or SMPS applications, MOSFETs or faster bipolar transistors (e.g., MJD122) are preferred. The TIP122TU remains suitable for fan speed control, lamp dimming, and relay sequencing where switching occurs at ≤1 kHz.

TIP122TU Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Obsolete

Transistor Type:: NPN - Darlington

Current - Collector (Ic) (Max):: 5 A

Voltage - Collector Emitter Breakdown (Max):: 100 V

Vce Saturation (Max) @ Ib, Ic:: 4V @ 20mA, 5A

Current - Collector Cutoff (Max):: 500µA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 1000 @ 3A, 3V

Power - Max:: 2 W

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220-3

TIP122TU FAQ

1.How can I place an order for TIP122TU through Aetrix?

Please submit a Request for Quotation (RFQ) for TIP122TU 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 TIP122TU reliable?

The price and inventory of TIP122TU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TIP122TU is usually 5 days.

3.What payment methods are accepted for TIP122TU?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TIP122TU transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TIP122TU?

TIP122TU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TIP122TU 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 TIP122TU?

For technical support, including TIP122TU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TIP122TU requirements.

6.How does Aetrix verify that TIP122TU is sourced from the original manufacturer or authorized distributors?

All TIP122TU 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 TIP122TU meets industry standards.

7.What is the process for return or replacement of TIP122TU?

All TIP122TU units undergo pre-shipment inspection (PSI). If there is an issue with TIP122TU, 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 TIP122TU part is unused and in its original packaging.

Return procedure for TIP122TU:

1.Submit a request within 90 days.

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

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