onsemi MPSW55G

Overview

MPSW55G from onsemi is a PNP silicon bipolar junction transistor designed for general-purpose low-power amplification and switching in linear and saturated operating regions. It features −60 V_CEO, −500 mA continuous collector current, 1.0 W total dissipation at T_A = 25°C, h_FE ≥ 100 at −50 mA/−1.0 V, and TO−92 (Case 29−10) Pb−free packaging - used in discrete audio preamplifier stages and relay driver circuits.

For engineers reviewing the MPSW55G datasheet, pinout, applications, or equivalent options, key selection considerations include its PNP polarity, −60 V breakdown rating, thermal resistance of 125°C/W (junction-to-ambient), DC current gain behavior across temperature, and compatibility with through-hole PCB layouts requiring 1 W power handling in compact form factor.

Technical Context

The MPSW55G operates as a medium-voltage, medium-current PNP BJT optimized for Class-A amplifier stages and active-low switch configurations. Its safe operating area (SOA) is defined by thermal limits (2.5 W at T_C = 25°C), second-breakdown constraints, and pulse-duty-cycle derating - critical for transient load handling in industrial control interfaces.

Electrical behavior is characterized by V_CE(sat) ≤ −0.5 V at I_C = −250 mA/I_B = −10 mA, V_BE(on) ≈ −1.2 V under same conditions, f_T = 50 MHz, and C_obo = 15 pF - supporting stable operation up to mid-VHF frequencies in emitter-follower or common-emitter topologies.

Key Specifications

Pinout & Package

Package: TO−92 (Case 29−10), Pb−free, straight-lead bulk pack (5000 units). Dimensions conform to ON Semiconductor mechanical drawing 98AON52857E Issue D.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BC557B and MPSA56, the MPSW55G offers balanced performance: sufficient −60 V rating for most industrial −24/−48 V rails, proven 1.0 W dissipation capability at ambient, and consistent h_FE ≥ 100 - making it optimal for cost-sensitive, medium-reliability linear and switching roles where neither ultra-high gain nor extreme voltage tolerance is required.

Availability

MPSW55G is available at Aetrix Electronics and suitable for audio preamplifier stages, relay driver circuits, and linear voltage regulator pass elements requiring stable component supply with RoHS-compliant through-hole packaging.

Supply support for MPSW55G 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, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The MPSW55G belongs to onsemi's legacy discrete bipolar transistor family engineered for general-purpose amplification and switching in cost-sensitive, high-volume industrial and consumer electronics - emphasizing manufacturability, thermal robustness, and Pb−free compliance.

FAQ

What is the maximum continuous collector current rating for the MPSW55G?

The MPSW55G has a maximum continuous collector current (I_C) rating of −500 mAdc at T_A = 25°C. This value decreases with rising ambient temperature due to the 8.0 mW/°C derating factor specified in the datasheet. At 70°C ambient, usable I_C drops to approximately −465 mA. The MPSW55G must be operated within this limit to avoid thermal runaway or bond-wire failure.

Is the MPSW55G pin-compatible with the MPSW56?

Yes, the MPSW55G and MPSW56 share identical TO−92 package dimensions, pinout (Emitter/Base/Collector on pins 1/2/3), and mechanical marking layout. However, they differ electrically: MPSW56 specifies −80 V_CEO and −80 V_VCBO, whereas MPSW55G is rated at −60 V for both. Substituting MPSW55G for MPSW56 is acceptable only if the application's maximum reverse voltage remains below −60 V.

What is the typical DC current gain (h_FE) of the MPSW55G at low collector currents?

The MPSW55G exhibits h_FE ≥ 100 at I_C = −50 mAdc and V_CE = −1.0 Vdc. At lower currents (e.g., −10 mA), h_FE rises to approximately 150–200, as shown in Figure 1 of the datasheet. This gain variation must be accounted for in precision biasing networks. The MPSW55G's h_FE remains stable across −55°C to +125°C junction temperatures, supporting wide-temperature industrial deployment.

Can the MPSW55G be used in switching applications with 20 kHz PWM signals?

Yes, the MPSW55G supports 20 kHz PWM switching due to its 50 MHz f_T and fast saturation characteristics (V_CE(sat) ≤ −0.5 V at I_C/I_B = 25). Switching losses remain low when base drive is optimized for turn-on/turn-off times < 1 μs. For reliable operation, ensure gate/base drive current exceeds −10 mA during turn-on and includes reverse-base recovery path. The MPSW55G's SOA curve confirms safe 20 kHz operation up to −250 mA with 50% duty cycle.

Does the MPSW55G have a documented thermal resistance from junction to case (R_JC)?

Yes, the MPSW55G specifies R_JC = 50°C/W at T_C = 25°C. This value reflects heat transfer from die to TO−92 case surface and is critical when mounting to external heatsinks or copper pads. Combined with R_JA = 125°C/W, it confirms that 80% of thermal resistance resides in the junction-to-ambient path - validating the need for PCB copper thermal relief and airflow in sustained 0.75 W applications. The MPSW55G's R_JC matches industry-standard TO−92 PNP transistors.