onsemi TIP29B

Overview

TIP29B from onsemi is an NPN silicon power transistor in a TO−220 package, rated for 80 V_CEO, 1.0 A continuous collector current, and 30 W total power dissipation at T_C = 25°C. It delivers h_FE ≥ 15 at I_C = 1.0 A, V_CE = 4.0 V, and V_CE(sat) ≤ 0.7 V under same conditions - used in linear amplifiers, relay drivers, and DC motor control stages.

For engineers reviewing the TIP29B datasheet, pinout, applications, or equivalent options, key selection criteria include its 80 V V_CEO rating, 1.0 A I_C capability, TO−220 thermal performance (R_JC = 4.167 °C/W), unclamped inductive energy handling (32 mJ), and complementary PNP pairing with TIP30B.

Technical Context

The TIP29B operates as a medium-power NPN bipolar junction transistor optimized for linear amplification and hard-switching applications. Its safe operating area (SOA) is defined up to 1 ms pulses at 80 V and 1.0 A, with second-breakdown-limited boundaries validated at T_J(pk) = 150°C.

It features a DC current gain (h_FE) of 15–75 depending on bias point, f_T = 3.0 MHz at I_C = 200 mA, and switching times (t_r, t_f, t_s′) characterized under controlled V_CC and I_C/I_B conditions - confirming suitability for moderate-speed switching below 100 kHz.

Key Specifications

Pinout & Package

Package: TO−220 (Case 221A, Style 1), through-hole, single-ended heatsink-mountable plastic power package with integral metal tab (pin 2 & 4 = collector).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TIP29B, MJD2955G offers higher current but requires PNP topology and SMT rework, while 2N3055G provides greater current headroom at the cost of voltage margin and outdated packaging - neither matches TIP29B's 80 V/1.0 A/TO−220 balance for new mid-voltage discrete designs.

Availability

TIP29B is available at Aetrix Electronics and suitable for audio amplifier output stages, DC motor control circuits, relay driver modules, and linear regulator pass elements requiring stable component supply across industrial, instrumentation, and legacy system repair programs.

Supply support for TIP29B 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 supplier specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The TIP29B belongs to onsemi's legacy silicon power transistor family designed for robust, cost-effective linear amplification and switching in general-purpose industrial and audio applications - emphasizing reliability, thermal stability, and Pb-free compliance.

FAQ

What is the maximum collector-emitter voltage rating for TIP29B?

The TIP29B has a maximum collector-emitter sustaining voltage (V_CEO(sus)) of 80 Vdc at I_C = 30 mA and I_B = 0. This rating is confirmed in the Electrical Characteristics table and defines the absolute upper limit for safe DC operation without breakdown. Exceeding 80 V risks permanent damage, especially under inductive load conditions. The TIP29B datasheet specifies this value explicitly for the TIP29BG/TIP29BG variant group, and it is not shared with lower-voltage variants like TIP29AG (60 V) or TIP29G (40 V).

Is TIP29B pin-compatible with other TIP29 series transistors?

Yes, all TIP29-series devices - including TIP29G, TIP29AG, TIP29BG, and TIP29CG - share identical TO−220 package dimensions, pinout (pin 1 = base, pins 2 & 4 = collector, pin 3 = emitter), and mechanical mounting. However, electrical ratings differ: V_CEO, V_CB, and SOA curves scale with voltage grade. Substituting TIP29B for a lower-grade variant is safe electrically; substituting a lower-grade part for TIP29B risks overvoltage failure.

What is the typical DC current gain (h_FE) of TIP29B at 1.0 A collector current?

The TIP29B exhibits h_FE ≥ 15 when tested at I_C = 1.0 A, V_CE = 4.0 V, and T_C = 25°C - a minimum guaranteed value per the datasheet's Electrical Characteristics table. At lower currents (e.g., I_C = 0.2 A), h_FE rises to 40–75. Designers must size base drive using the 15× minimum to ensure saturation across temperature and unit variation. The TIP29B's h_FE is not interchangeable with TIP29CG, which shares the same test condition but may show different distribution.

Can TIP29B be used in switching applications, and what is its switching speed?

Yes, the TIP29B is characterized for switching use, with documented turn-on time (t_r), turn-off time (t_f), and storage time (t_s′) in Figures 2–4. At V_CC = 10 V and I_C/I_B = 10, t_r ≈ 0.7 μs and t_f ≈ 0.7 μs. Its f_T = 3.0 MHz confirms suitability for audio and low-speed digital switching (<100 kHz), but not RF or high-frequency SMPS. The TIP29B's 32 mJ unclamped inductive energy rating further validates its robustness in relay and solenoid drive.

Does TIP29B require a heatsink in normal operation?

Yes - the TIP29B's 30 W power dissipation rating applies only at T_C = 25°C, meaning the case temperature must be held at or below 25°C to sustain full power. In practice, even at 5–10 W dissipation, thermal resistance from junction-to-ambient (R_JA = 62.5 °C/W) causes rapid temperature rise without heatsinking. A heatsink with R_θSA ≤ 10 °C/W is recommended for continuous >1 W operation. The metal tab (collector) must be electrically isolated unless the circuit design intentionally references collector to chassis ground.