onsemi 2SB631E

Overview

2SB631E from onsemi is a PNP epitaxial planar silicon power transistor in TO-126 package, rated for V_CEO = –100 V, I_C = –1 A, and P_C = 1 W at T_C = 25 °C, with low V_CE(sat) of –0.4 V at I_C = –500 mA and h_FE ≥ 60 at I_C = –50 mA - used in low-frequency power amplifier stages and linear regulator pass elements.

For engineers reviewing the 2SB631E datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, thermal derating curves, saturation behavior under DC bias, h_FE linearity across collector current, and real-world switching time test conditions per ON Semiconductor's ENN346G specification.

Technical Context

This PNP transistor operates in linear and switching modes with guaranteed breakdown voltage (V_CEO = –100 V) and safe operating area defined up to T_C = 150 °C. Its h_FE is binned (Rank D: 120–160) and specified at two test points: I_C = –50 mA and –500 mA, confirming stable gain over wide current range.

Switching performance is characterized using standardized test circuit (IB1/IB2 drive, 20 µs pulse width), yielding t_f = 100 ns and t_r = 10 ns. Output capacitance C_ob = 70 pF at V_CB = –10 V supports predictable frequency response in audio and DC-DC feedback paths.

Key Specifications

Pinout & Package

2SB631E is housed in TO-126 package (SANYO designation), with standard lead assignment: Pin 1 = Emitter, Pin 2 = Collector, Pin 3 = Base. The case is electrically connected to the collector terminal.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 2SB772 and MJD2955, the 2SB631E uniquely balances –100 V breakdown, –1 A current, TO-126 compactness, and h_FE linearity - making it optimal for space-constrained 48 V linear and audio applications where thermal and voltage margins are critical.

Availability

2SB631E is available at Aetrix Electronics and suitable for audio power amplifiers, linear voltage regulators, DC-DC error amplifiers, and industrial relay drivers requiring stable component supply across extended temperature and long-life programs.

Supply support for 2SB631E 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 2SB631E belongs to onsemi's legacy bipolar power transistor family designed specifically for low-frequency linear and switching applications in industrial controls, audio equipment, and power management subsystems.

FAQ

What is the maximum junction temperature for the 2SB631E?

The 2SB631E has a maximum junction temperature (T_j) of +150 °C, consistent with its absolute maximum rating for junction temperature. This value is confirmed in the "Absolute Maximum Ratings" table of the official datasheet (ENN346G, Rev. 0). Derating begins above T_C = 25 °C, and the device must be mounted with appropriate thermal interface to maintain T_j ≤ 150 °C under worst-case load. The 2SB631E's thermal resistance θ_JC is not explicitly published, but its PC–T_C curve shows 1 W dissipation at T_C = 25 °C and 0 W at T_C = 150 °C.

Is the 2SB631E pin-compatible with the 2SB631K variant?

Yes, the 2SB631E and 2SB631K share identical TO-126 package dimensions and pinout (Emitter–Collector–Base), and both are PNP transistors with same V_CEO, I_C, and P_C ratings. The 'K' suffix denotes a tighter h_FE bin (120–160), while 'E' corresponds to Rank D (60–120) per the datasheet's h_FE classification table. No PCB changes are required when substituting 2SB631E for 2SB631K in non-critical gain applications.

Does the 2SB631E require a heatsink in 1 W continuous operation?

Yes - the 2SB631E dissipates 1 W only at case temperature T_C = 25 °C, as shown in the PC–T_C derating curve. At ambient temperatures above 25 °C or with any internal power dissipation >0.5 W, thermal management is mandatory. Without a heatsink, the device reaches thermal shutdown rapidly; typical designs use a 50 × 50 × 1.5 mm aluminum heatsink with silicone grease, enabling ~0.6 W dissipation at T_A = 50 °C. The 2SB631E's metal tab is electrically connected to the collector, so isolation is required if the heatsink is grounded.

What is the typical Cob (output capacitance) of the 2SB631E at VCB = –10 V?

The typical output capacitance (C_ob) of the 2SB631E is 70 pF at V_CB = –10 V and f = 1 MHz, as measured and plotted in Figure ITR08280 of the ENN346G datasheet. This value falls within the 50–90 pF range observed across the 2SB631/2SB631K family and directly impacts small-signal bandwidth and switching speed in amplifier and driver circuits. Designers should use this C_ob value when calculating Miller effect gain roll-off or optimizing compensation networks around the 2SB631E.

Can the 2SB631E be used as a direct replacement for the 2SA1015 in existing designs?

No - the 2SB631E is not a direct replacement for the 2SA1015. While both are PNP transistors, the 2SA1015 has V_CEO = –50 V and P_C = 0.4 W, whereas the 2SB631E offers –100 V and 1 W. Substituting the 2SB631E may cause excessive base drive due to higher h_FE (60–160 vs. 70–240), and its larger TO-126 package does not fit the 2SA1015's TO-92 footprint. The 2SB631E can replace 2SA1015 only after verifying SOA, bias network compatibility, and mechanical layout - it is not a drop-in solution.