onsemi TIP35B

Overview

TIP35B from onsemi is an NPN silicon power transistor designed for high-current switching and linear amplifier applications, with 25 A continuous collector current, 80 V collector-emitter sustaining voltage (V_CEO(sus)), and 125 W total power dissipation at T_C = 25°C - used in motor control circuits, DC-DC converter output stages, and audio power amplifiers.

For engineers reviewing the TIP35B datasheet, pinout, applications, or equivalent options, key selection considerations include its TO-247 package thermal resistance (R_JC = 1.0 °C/W), unclamped inductive load capability (90 mJ), and verified h_FE ≥ 15 at 15 A - critical for robust thermal design and reliable high-current saturation performance.

Technical Context

The TIP35B operates as a general-purpose NPN bipolar junction transistor optimized for high-power linear and switching operation. Its safe operating area (SOA) is defined up to 100 V and 25 A under DC conditions, with second-breakdown-limited pulse capability validated at 10 ms and 10% duty cycle.

It features low leakage (I_CEO ≤ 1.0 mA at V_CE = 60 V), moderate gain-bandwidth product (f_T ≥ 3.0 MHz at I_C = 1.0 A), and base-emitter on voltage of 2.0–4.0 V across 15–25 A - confirming suitability for direct-drive or low-gain-driver interface topologies.

Key Specifications

Pinout & Package

Package: TO-247 (Case 340L, Style 3), Pb-free, with 4-terminal configuration: Pin 1 = Base, Pin 2 = Collector, Pin 3 = Emitter, Pin 4 = Collector (dual-collector tab for enhanced current handling and thermal path).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MJE13009 and 2N3055G, the TIP35B delivers superior continuous current handling (25 A), higher power dissipation (125 W), better thermal resistance (1.0 °C/W), and documented unclamped inductive robustness (90 mJ) - making it the preferred choice for modern high-reliability, high-power linear and switching designs.

Availability

TIP35B is available at Aetrix Electronics and suitable for DC motor drives, audio power amplifiers, and switching regulator output stages requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for TIP35B 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 management, analog, sensor, and connectivity solutions for automotive, industrial, and consumer markets.

The TIP35B belongs to onsemi's complementary high-power transistor family designed specifically for ruggedized linear amplification and switching in industrial motor controls, power supplies, and audio systems - emphasizing SOA integrity, thermal reliability, and manufacturability.

FAQ

What is the maximum collector-emitter voltage rating for the TIP35B?

The TIP35B has a collector-emitter sustaining voltage (V_CEO(sus)) rating of 80 V, tested at I_C = 30 mA and I_B = 0. This is distinct from breakdown voltage and reflects the device's guaranteed blocking capability under specified conditions. Exceeding this voltage risks avalanche failure, especially under inductive switching transients. The TIP35B datasheet confirms this value in the Maximum Ratings table and SOA curves.

Does the TIP35B have a dual-collector configuration, and how does it affect PCB layout?

Yes, the TIP35B in TO-247 package features four terminals: Pin 1 (Base), Pin 2 (Collector), Pin 3 (Emitter), and Pin 4 (Collector). Pins 2 and 4 are internally connected to the same collector region and metal tab. This dual-collector design reduces effective current density and improves thermal spreading - requiring both pins to be routed to the same high-current net and thermally connected to the heatsink. It does not support independent collector routing.

What is the minimum DC current gain (h_FE) of the TIP35B at high current, and why does it matter?

The TIP35B guarantees h_FE ≥ 15 at I_C = 15 A and V_CE = 4.0 V. This minimum gain determines the required base drive current (e.g., ≥1.0 A for 15 A collector current), directly impacting driver stage sizing and power loss. Unlike typical values, this guaranteed minimum ensures consistent saturation behavior across production lots and temperature extremes - critical for reliable high-current switching.

Can the TIP35B be used in place of the TIP35A or TIP35C, and what are the key differences?

No - the TIP35B is not interchangeable with TIP35A or TIP35C without circuit review. TIP35A is rated for 60 V V_CEO(sus), TIP35B for 80 V, and TIP35C for 100 V. All share identical package, pinout, and thermal specs, but voltage rating is the sole differentiating parameter. Substituting a lower-voltage variant risks premature breakdown; substituting a higher-voltage variant may exhibit slightly lower h_FE and higher V_CE(sat) at same current.

What thermal derating applies to the TIP35B above 25°C case temperature?

The TIP35B's total power dissipation must be derated linearly above 25°C case temperature at 1.0 W/°C, based on its R_JC = 1.0 °C/W. For example, at T_C = 75°C, maximum allowable P_D drops to 75 W. This derating is mandatory to prevent junction temperature from exceeding +150°C. The derating curve is explicitly shown in Figure 1 of the official TIP35/D datasheet.