onsemi MPSA56

Overview

MPSA56 from ON Semiconductor is a PNP general-purpose amplifier transistor designed for linear amplification and switching in low-to-medium power circuits, with V_CEO = –60 V, I_C = –500 mA, h_FE ≥ 100 at I_C = –10 mA, and f_T = 50 MHz - commonly used in audio preamplifier stages, relay drivers, and discrete logic inverters.

For engineers reviewing the MPSA56 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, TO-92 package mapping, terminal roles, real-world use cases, and two validated alternative transistors - all aligned to Fairchild/ON Semiconductor's official specifications for MPSA56.

Technical Context

The MPSA56 operates as a silicon PNP bipolar junction transistor optimized for DC-coupled amplification and saturated switching. Its design supports continuous collector currents up to –500 mA with V_CE(sat) ≤ –0.25 V at I_C = –100 mA / I_B = –10 mA and V_BE(on) ≈ –1.2 V under same conditions.

Thermal performance is defined by R_θJA = 200 °C/W (TO-92, FR-4 PCB), enabling stable operation from –55 °C to +150 °C junction temperature. It shares process lineage with the MPSA06 family but differs in polarity, voltage rating, and gain profile - not interchangeable without circuit revalidation.

Key Specifications

Pinout & Package

Package: TO-92 (3-lead molded plastic), lead-form: straight, standard pinout per JEDEC TO-92 outline. Mounting requires no heatsink for ≤300 mW dissipation at 25 °C ambient.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP general-purpose amplifier applications.

Compared with 2N3906 and BC557, the MPSA56 offers superior voltage margin (–60 V vs. –40/–45 V) and higher continuous current (–500 mA), making it more robust for 48 V telecom interfaces and industrial relay banks where reliability under transient stress is critical.

Availability

MPSA56 is available at Aetrix Electronics and suitable for audio signal conditioning, relay driving, discrete logic inversion, and current mirror reference applications requiring stable component supply across production lifecycles.

Supply support for MPSA56 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

ON Semiconductor is a global semiconductor manufacturer specializing in energy-efficient power management, analog, sensors, and logic devices for automotive, industrial, and cloud infrastructure markets.

The MPSA56 belongs to ON Semiconductor's legacy general-purpose bipolar transistor portfolio - engineered for reliability in discrete amplifier and switching functions where cost, thermal stability, and manufacturability are prioritized over ultra-high-speed or RF performance.

FAQ

What is the maximum collector-emitter voltage rating for the MPSA56?

The MPSA56 has a V_CEO rating of –60 V, meaning it can safely block up to 60 volts in reverse bias between collector and emitter with base open. This rating is confirmed in the Absolute Maximum Ratings table of the official ON Semiconductor datasheet and applies at T_A = 25 °C. Operation near this limit requires verification of SOA compliance under actual load conditions.

Is the MPSA56 pin-compatible with the 2N3906?

Yes, the MPSA56 uses the same TO-92 package and E-B-C pinout as the 2N3906, enabling direct physical replacement on PCBs. However, the MPSA56 offers higher V_CEO (–60 V vs. –40 V) and I_C (–500 mA vs. –200 mA), so functional substitution requires checking whether the original design fully utilizes those margins.

What is the typical DC current gain (h_FE) of the MPSA56 at 10 mA collector current?

The MPSA56 exhibits h_FE ≥ 100 at I_C = –10 mA and V_CE = –1 V, per the Electrical Characteristics table in the ON Semiconductor datasheet. This value is guaranteed minimum; typical units measure 150–250, supporting predictable biasing in Class-A amplifiers and emitter followers.

Can the MPSA56 be used in switching applications?

Yes, the MPSA56 is routinely used in saturated switching due to its low V_CE(sat) ≤ –0.25 V at I_C = –100 mA / I_B = –10 mA and fast turn-off characteristics. Its f_T = 50 MHz supports switching up to ~500 kHz with acceptable rise/fall times, though gate-driving MOSFETs is preferred for >1 MHz operation.

What is the thermal resistance (R_θJA) of the MPSA56 in TO-92 package?

The MPSA56 has an R_θJA of 200 °C/W when mounted on a standard FR-4 PCB (1.6″ × 1.6″ × 0.06″). This value defines how much junction temperature rises per milliwatt of dissipated power and must be used with actual P_D to verify thermal safety - e.g., at 300 mW dissipation, ΔT = 60 °C above ambient.