onsemi TIP111

Overview

TIP111 from ON Semiconductor is an NPN epitaxial silicon Darlington transistor in a TO-220 package, rated for 80 V V_CEO, 2 A DC collector current, and 50 W collector dissipation at T_C = 25°C. It features monolithic construction with built-in base-emitter shunt resistors (R₁ ≈ 10 kΩ, R₂ ≈ 0.6 kΩ), h_FE ≥ 1000 at I_C = 1 A, and V_CE(sat) ≤ 2.5 V at I_C = 2 A / I_B = 8 mA - used in industrial linear power control and relay driver circuits.

For engineers reviewing the TIP111 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, thermal derating behavior, safe operating area limits, junction temperature constraints, and direct alternatives for high-gain, medium-power switching designs requiring low drive current and robust saturation performance.

Technical Context

The TIP111 integrates two cascaded NPN transistors in a single die with internal biasing resistors, enabling high DC current gain without external base network components. Its Darlington configuration provides I_C/I_B amplification >1000 while maintaining V_BE(on) ≈ 2.8 V at I_C = 2 A.

Designed for linear and switching operation up to 150°C junction temperature, it supports pulse currents up to 4 A (ICP) and exhibits Cob = 100 pF at V_CB = 10 V, f = 0.1 MHz - suitable for moderate-speed industrial interface and load-driving applications where thermal stability and drive simplicity are prioritized over RF performance.

Key Specifications

Pinout & Package

Package: TO-220, 3-lead, single-gauge, through-hole molded plastic housing with metal tab (collector-connected). Standard JEDEC variation AB footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TIP121 and MJ11012, the TIP111 offers balanced performance for 80 V industrial switching with standardized TO-220 mounting, lower cost than TO-3 alternatives, and sufficient gain/saturation for microcontroller-driven loads - making it optimal for cost-sensitive, thermally constrained embedded power interfaces.

Availability

TIP111 is available at Aetrix Electronics and suitable for industrial motor control, relay replacement, lamp dimming, and linear regulator applications requiring stable component supply, long-term lifecycle support, and traceable sourcing from authorized channels.

Supply support for TIP111 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 is a global semiconductor manufacturer specializing in power management, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The TIP111 belongs to ON Semiconductor's legacy power bipolar transistor family, originally developed by Fairchild Semiconductor for rugged, high-gain industrial switching - emphasizing reliability, thermal robustness, and ease of drive in non-RF, medium-speed applications.

FAQ

What is the maximum collector-emitter voltage rating for the TIP111?

The TIP111 has a maximum collector-emitter sustaining voltage (V_CEO(sus)) of 80 V under test conditions of I_C = 30 mA and I_B = 0. This rating is confirmed in the Absolute Maximum Ratings table and Electrical Characteristics section of the official datasheet. Operating the TIP111 above 80 V risks avalanche breakdown and permanent damage. Designers should maintain at least 20% voltage margin below 80 V in real-world circuits with transient spikes. The TIP111 is not rated for 100 V operation - that specification applies only to the TIP112 variant.

Does the TIP111 require external base resistors for proper operation?

No, the TIP111 does not require external base resistors because it integrates monolithic base-emitter shunt resistors: R₁ ≈ 10 kΩ between base and emitter, and R₂ ≈ 0.6 kΩ between base and collector. These resistors ensure reliable turn-off and prevent leakage-induced false triggering. While external series base resistors may still be used for current limiting from logic drivers, they are not mandatory for basic functionality - unlike discrete Darlington configurations. This feature simplifies PCB layout and improves system reliability in the TIP111.

What is the thermal resistance from junction to case (R_θJC) for the TIP111?

The TIP111 datasheet does not explicitly list R_θJC as a standalone parameter, but its thermal performance is defined via the collector dissipation rating: 50 W at T_C = 25°C. From this, R_θJC can be derived as approximately 1.0°C/W using the formula R_θJC = (T_J(max) − T_C) / P_C = (150°C − 25°C) / 50 W. This value assumes ideal mounting to a large heatsink; actual thermal resistance will increase with poor thermal interface materials or undersized heatsinks. Always verify junction temperature in situ using the TIP111's specified derating curve.

Can the TIP111 be used as a direct replacement for the TIP110 or TIP112?

The TIP111 is pin-compatible and functionally similar to the TIP110 and TIP112, but it is not a universal drop-in replacement due to differing voltage ratings: TIP110 is rated for 60 V V_CEO, TIP111 for 80 V, and TIP112 for 100 V. Substituting the TIP111 for a TIP110 is generally safe if voltage stress remains below 80 V; however, replacing a TIP112 with a TIP111 risks overvoltage failure in 100 V circuits. Always validate voltage margins, power dissipation, and safe operating area curves before interchanging TIP110/TIP111/TIP112 variants in existing designs.

What is the typical DC current gain (h_FE) of the TIP111 at 2 A collector current?

The TIP111 guarantees h_FE ≥ 500 at V_CE = 4 V and I_C = 2 A, per the Electrical Characteristics table. This is lower than its minimum gain of 1000 at I_C = 1 A, reflecting expected gain compression at higher current densities. Designers should size base drive accordingly - e.g., 4 mA base current ensures ≥2 A collector current even at worst-case h_FE. The TIP111's gain remains stable across temperature, supporting consistent performance in industrial environments without recalibration.