onsemi TIP35A

Overview

TIP35A from onsemi is an NPN silicon power transistor designed for high-current switching and linear amplifier applications, with 25 A continuous collector current, 60 V collector-emitter sustaining voltage (V_CEO(sus)), 125 W total power dissipation at T_C = 25°C, and DC current gain (h_FE) of 40 typical at I_C = 15 A - used in audio output stages, motor drivers, and DC-DC converter switches.

For engineers reviewing the TIP35A datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, TO-247 package layout, thermal resistance data (R_JC = 1.0 °C/W), safe operating area curves, and real-world substitution guidance for industrial power design validation.

Technical Context

The TIP35A operates as a medium-speed, high-current NPN bipolar junction transistor optimized for linear and saturated switching modes. Its h_fe ≥ 3.0 MHz bandwidth product at I_C = 1.0 A and f = 1.0 MHz supports stable gain in audio-frequency amplifiers, while its low leakage (I_CEO ≤ 1.0 mA at V_CE = 30 V) ensures reliability in high-temperature bias networks.

Thermal design is constrained by R_JC = 1.0 °C/W and R_JA = 35.7 °C/W, requiring heatsinking for sustained >30 W operation. The device's unclamped inductive load rating (E_SB = 90 mJ) and reverse-bias SOA compliance enable robust use in relay drivers and solenoid controls without external snubbers.

Key Specifications

Pinout & Package

Package: TO-247 (Case 340L, Style 3), Pb-free, with metal tab electrically connected to collector. Requires insulated mounting hardware when collector is not at chassis ground.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJE13009 and 2N3055, the TIP35A delivers superior current-handling (25 A), lower saturation loss (1.8 V), and modern thermal packaging (TO-247 with R_JC = 1.0 °C/W), making it optimal for new designs demanding high-efficiency, high-reliability power switching at 60 V class.

Availability

TIP35A is available at Aetrix Electronics and suitable for audio amplifier output stages, industrial motor drives, and regulated power supply designs requiring stable component supply, long-term manufacturability, and RoHS-compliant packaging.

Supply support for TIP35A 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, and cloud infrastructure markets.

The TIP35A belongs to onsemi's legacy high-power bipolar transistor family, engineered for ruggedized linear and switching applications where high current, thermal robustness, and proven reliability are essential - particularly in industrial control and audio systems.

FAQ

What is the maximum safe collector-emitter voltage for TIP35A?

The TIP35A has a collector-emitter sustaining voltage (V_CEO(sus)) rating of 60 V, tested at I_C = 30 mA with base open. Exceeding this voltage risks avalanche breakdown and permanent damage. For inductive load switching, ensure voltage transients remain within the reverse-bias SOA limits shown in Figure 7 of the datasheet, especially during turn-off.

Can TIP35A be used in parallel with other transistors to increase current capacity?

Yes, TIP35A can be paralleled, but requires emitter ballasting resistors (typically 0.1 Ω) to ensure current sharing due to h_FE variation. The device's positive temperature coefficient of V_CE(sat) aids thermal stability, but mismatched thermal mounting will cause current hogging. Always verify shared current distribution under worst-case load and temperature conditions for TIP35A.

Is TIP35A pin-compatible with TIP35B or TIP35C?

No - TIP35A, TIP35B, and TIP35C share identical pinout and package (TO-247), but differ in voltage ratings: TIP35A = 60 V, TIP35B = 80 V, TIP35C = 100 V. Substituting TIP35A for higher-voltage variants risks overvoltage failure in circuits operating near 70–100 V; always match the suffix letter to the application's maximum V_CE requirement.

What is the recommended heatsink thermal resistance for continuous 25 A operation of TIP35A?

To sustain 25 A continuous current, TIP35A dissipates up to ~45 W (based on V_CE(sat) ≈ 1.8 V). With R_JC = 1.0 °C/W and max T_J = +150°C, ambient ≤ +40°C, the required heatsink thermal resistance (R_SA) must be ≤ 1.8 °C/W including interface material. Use forced air or ≥ 300 cm² aluminum heatsink for reliable operation.

Does TIP35A require a base resistor, and how is its value calculated?

Yes - TIP35A requires a series base resistor to limit I_B and prevent thermal runaway. For saturation at I_C = 25 A, assume h_FE = 25 (min), so I_B ≥ 1.0 A. With V_BE(on) ≈ 2.0 V and drive voltage = 12 V, R_B = (12 − 2)/1.0 = 10 Ω, 5 W minimum. Always verify base drive capability and transient response in actual circuit conditions for TIP35A.