onsemi TIP29

Overview

TIP29 from onsemi is an NPN silicon power transistor in a TO-220 package, rated for 40 V_CEO, 1.0 A continuous collector current, and 30 W total power dissipation at T_C = 25°C. It serves as a general-purpose amplifier and switching device in linear power supplies, motor drivers, and relay drivers where robust thermal performance and proven ruggedness are required.

For engineers reviewing the TIP29 datasheet, pinout, applications, or equivalent options, key selection considerations include its V_CEO = 40 V rating, h_FE = 40–75 (at I_C = 0.2 A), V_CE(sat) ≤ 0.7 V, R_JC = 4.167 °C/W, and unclamped inductive energy handling of 32 mJ - all critical for reliable operation in medium-power discrete switching circuits.

Technical Context

The TIP29 operates as a bipolar junction transistor with fixed NPN polarity, designed for linear amplification and hard-switching applications up to 3 MHz bandwidth (f_T = 3.0 MHz). Its safe operating area (SOA) is defined by thermal limits at DC and pulse conditions, second-breakdown constraints, and bonding-wire current capacity.

It features a complementary PNP counterpart (TIP30G), shares identical TO-220 mechanical outline (Case 221A, Style 1), and supports mounting via the collector-connected tab for heatsink integration. Base-emitter voltage is specified at ≤1.3 V under I_C = 1.0 A, and leakage currents (I_CEO ≤ 0.3 mA, I_CES ≤ 200 µA) are validated per JEDEC test conditions.

Key Specifications

Pinout & Package

Package: TO-220 (Case 221A, Style 1), 3-terminal plastic power package with metal tab connected to collector; lead-free (G-suffix), RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJD2955G and 2N3055, the TIP29 offers optimized balance of cost, TO-220 mountability, and 40 V/1 A capability for mid-power discrete switching - making it preferable where space, thermal management simplicity, and supply chain continuity are prioritized over extreme voltage or current ratings.

Availability

TIP29 is available at Aetrix Electronics and suitable for linear power supply regulation, DC motor speed control, relay driver circuits, and audio power amplifier stages requiring stable component supply and long-term manufacturability.

Supply support for TIP29 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, and cloud infrastructure markets.

The TIP29 belongs to onsemi's legacy plastic power transistor family, engineered for reliability in general-purpose amplifier and switching applications where proven ruggedness, thermal stability, and ease of heatsink integration are essential.

FAQ

What is the maximum collector-emitter voltage rating for the TIP29?

The TIP29 has a maximum collector-emitter sustaining voltage (V_CEO(sus)) of 40 Vdc, tested at I_C = 30 mA and I_B = 0. This rating defines the absolute upper limit for voltage applied between collector and emitter in open-base conditions. Exceeding 40 V risks avalanche breakdown and permanent damage. The TIP29G variant maintains this specification and is validated per JEDEC JESD22-A114.

Does the TIP29 require a heatsink in normal operation?

Yes, the TIP29 requires a heatsink when dissipating more than ~2 W continuously. With R_JC = 4.167 °C/W and R_JA = 62.5 °C/W, junction temperature rises rapidly without thermal management. For example, at I_C = 1.0 A and V_CE = 2 V (2 W dissipation), T_J exceeds 100°C without a heatsink at 25°C ambient. The metal tab (pins 2 & 4) is electrically connected to the collector and must be isolated from chassis ground unless intended as common reference.

What is the DC current gain (h_FE) range for the TIP29 at typical operating conditions?

The TIP29 exhibits h_FE = 40–75 when measured at I_C = 0.2 A and V_CE = 4.0 Vdc, per the onsemi datasheet. At higher currents (I_C = 1.0 A), h_FE drops to ≥15. This wide spread means base drive must be designed for worst-case gain (h_FE = 40 minimum) to ensure saturation across production lots. The TIP29G part number reflects the Pb-free version but retains identical h_FE specifications.

Can the TIP29 be used as a direct replacement for the TIP29A, TIP29B, or TIP29C?

No - the TIP29 is not a direct replacement for TIP29A/B/C due to differing V_CEO ratings: TIP29 = 40 V, TIP29A = 60 V, TIP29B = 80 V, TIP29C = 100 V. All share identical pinout, package, and thermal specs, but substituting TIP29 for a higher-voltage variant risks premature failure in circuits operating near their voltage limits. Always verify V_CE stress margins before interchange.

What is the safe operating area (SOA) limitation for the TIP29 at DC operation?

At DC, the TIP29's SOA is thermally limited to 30 W at T_C = 25°C, derating linearly by 0.24 W/°C above that temperature. Second-breakdown limits begin to dominate above ~10 V_CE and >0.5 A, especially at elevated case temperatures. Figure 5 in the onsemi TIP29B/D datasheet shows the DC boundary is defined by the "THERMALLY LIMITED @ T_C = 25°C" curve - meaning sustained operation beyond this envelope risks irreversible junction failure.