onsemi TIP140

Overview

TIP140 from ON Semiconductor is an NPN Darlington silicon power transistor designed for low-frequency switching and general-purpose amplifier applications, featuring V_CEO(sus) = 60 Vdc (min), I_C = 10 A continuous, h_FE ≥ 1000 at I_C = 5.0 A/V_CE = 4 V, and monolithic construction with built-in base-emitter shunt resistor - used in motor control circuits requiring high-current gain and robust thermal performance.

For engineers reviewing the TIP140 datasheet, pinout, applications, or equivalent options, key selection considerations include its 125 W power dissipation capability, TO-218 (SOT-93) package with 1.0 °C/W junction-to-case thermal resistance, collector-emitter saturation voltage of 2.0 V at 5.0 A/10 mA drive, and suitability for industrial relay drivers and DC motor starters.

Technical Context

The TIP140 integrates two cascaded NPN transistors in a monolithic Darlington configuration, delivering high DC current gain while maintaining single-package simplicity. Its internal base-emitter shunt resistor enables reliable turn-off without external bias networks, and it operates within −65 °C to +150 °C junction temperature range.

Designed for linear and switching operation below audio frequencies, the device exhibits 2.5 µs storage time and 2.5 µs fall time under resistive load conditions (V_CC = 30 V, I_C = 5.0 A, I_B = 20 mA), with safe operating area limited by both thermal constraints and secondary breakdown at elevated V_CE.

Key Specifications

Pinout & Package

Package: SOT-93 (TO-218), case 340D, 4-terminal metal-can package with isolated collector tabs. Mounting surface is electrically connected to collector terminals.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TIP140, TIP141 offers higher voltage safety margin without changing footprint or drive requirements, while MJ11015 trades integrated convenience for higher voltage capability and different thermal/mechanical integration needs.

Availability

TIP140 is available at Aetrix Electronics and suitable for industrial motor control, PLC output stages, and linear power supply designs requiring stable component supply, long-term manufacturability, and legacy-compatible through-hole power transistors.

Supply support for TIP140 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

ON Semiconductor (now part of onsemi) is a global supplier of energy-efficient semiconductor solutions, specializing in power management, analog, sensors, and discrete devices for automotive, industrial, and cloud infrastructure markets.

The TIP140 belongs to the Darlington Complementary Silicon Power Transistor family, engineered for cost-effective, high-gain switching and amplification in non-RF, low-frequency industrial power electronics.

FAQ

What is the maximum continuous collector current rating for the TIP140?

The TIP140 is rated for 10 A continuous collector current (I_C) at case temperature T_C = 25 °C. This rating assumes proper heatsinking to maintain junction temperature within −65 °C to +150 °C. At elevated case temperatures, derating applies per Figure 10 in the datasheet - for example, at T_C = 100 °C, maximum I_C drops to approximately 5.5 A. The TIP140 must be mounted on a heatsink capable of achieving ≤1.0 °C/W thermal resistance to sustain full 10 A operation.

Does the TIP140 have an integrated base-emitter shunt resistor, and what is its function?

Yes, the TIP140 features a monolithically integrated base-emitter shunt resistor. Its function is to provide a defined discharge path for stored base charge during turn-off, ensuring reliable and rapid cutoff without requiring external pull-down components. This simplifies driver circuitry - especially in microcontroller-based systems - and prevents unintended conduction due to leakage currents or noise coupling. The resistor value is not specified separately but is optimized to work with the Darlington's inherent gain characteristics, as confirmed in the schematic diagram on page 2 of the TIP140/D datasheet.

What is the typical V_CE(sat) of the TIP140 under standard test conditions?

The typical V_CE(sat) of the TIP140 is 2.0 V at I_C = 5.0 A and I_B = 10 mA, with a maximum of 3.0 V at I_C = 10 A and I_B = 40 mA. This saturation voltage directly determines conduction losses - for example, at 5 A, power dissipation in the TIP140 is 10 W just from V_CE(sat), excluding base drive loss. Designers must account for this in thermal calculations and ensure sufficient heatsinking, particularly in high-duty-cycle or linear-regulator applications where the TIP140 remains partially or fully saturated.

Can the TIP140 be used as a direct replacement for the TIP120 in existing designs?

No, the TIP140 is not a direct replacement for the TIP120. While both are NPN Darlington transistors, the TIP140 has higher power dissipation (125 W vs. 50 W), higher current rating (10 A vs. 5 A), and different pinout: TIP140 uses a 4-pin TO-218 package (Base, Collector, Emitter, Collector), whereas TIP120 uses a 3-pin TO-220 (Base, Collector, Emitter). Mechanical fit, thermal interface, and PCB layout are incompatible. Substitution would require redesign of mounting, heatsinking, and trace routing - and may introduce overvoltage risk if the original design relied on TIP120's lower V_CEO (80 V vs. TIP140's 60 V).

What is the safe operating area (SOA) limitation that most commonly affects TIP140 in switching applications?

The most common SOA limitation for the TIP140 in switching applications is secondary breakdown, especially during unclamped inductive turn-off events. As shown in Figure 6 of the datasheet, at V_CE > 30 V and I_C > 2 A, the device enters the secondary breakdown region unless pulse width is strictly limited. For example, at V_CE = 40 V and I_C = 3 A, the maximum allowable pulse width is ~10 µs. Designers must use snubbers or clamping diodes - or select higher-V_CEO variants like TIP141 - to avoid destructive failure when driving inductive loads such as relays or motors without suppression.