onsemi MPSA27_D75Z

Overview

MPSA27_D75Z from ON Semiconductor (formerly Fairchild) is an NPN general-purpose amplifier transistor designed for high-current-gain linear amplification and switching applications up to 500 mA collector current. It features V_CEO = 60 V, h_FE ≥ 10,000 at I_C = 10 mA, V_CE(sat) = 1.5 V at I_C = 100 mA / I_B = 0.1 mA, and f_T = 125 MHz - used in audio preamplifier stages and relay driver circuits.

For engineers reviewing the MPSA27_D75Z datasheet, pinout, applications, or equivalent options, key selection considerations include guaranteed minimum h_FE, low V_CE(sat) at moderate drive, thermal resistance (R_θJA = 200 °C/W on FR-4), TO-92 mechanical compatibility, and junction temperature range (–55 °C to +150 °C).

Technical Context

This NPN bipolar junction transistor operates in active, saturation, and cutoff regions with DC current gain specified across two test points: h_FE ≥ 10,000 at I_C = 10 mA and I_C = 100 mA, both at V_CE = 5.0 V. Its f_T of 125 MHz supports small-signal amplification up to VHF band.

Thermal design relies on R_θJA = 200 °C/W (TO-92, FR-4 PCB 36 mm × 18 mm × 1.5 mm, 6 cm² collector pad), and absolute maximum ratings include P_D = 625 mW at T_A = 25 °C with 5.0 mW/°C derating - requiring careful power dissipation management above ambient.

Key Specifications

Pinout & Package

Package: TO-92 (3-lead plastic through-hole). Standard lead configuration: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN amplifier applications.

Compared with MPSA27_D75Z, MPSA28_D75Z provides headroom for higher-voltage rails without sacrificing gain, while BC547C trades gain for speed and cost - making MPSA27_D75Z the preferred choice for precision, low-drive, medium-power linear amplification.

Availability

MPSA27_D75Z is available at Aetrix Electronics and suitable for audio preamplifiers, relay drivers, and industrial sensor signal conditioning requiring stable component supply, consistent h_FE binning, and TO-92 mechanical compatibility.

Supply support for MPSA27_D75Z 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 (acquired Fairchild Semiconductor in 2016) is a global supplier of energy-efficient semiconductor components for automotive, industrial, cloud computing, and IoT applications.

The MPSA27_D75Z belongs to the legacy Fairchild "MPSA" general-purpose amplifier family, engineered specifically for high-current-gain linear amplification and robust switching in cost-sensitive industrial controls and consumer audio equipment.

FAQ

What is the guaranteed minimum h_FE for MPSA27_D75Z?

The MPSA27_D75Z guarantees h_FE ≥ 10,000 at I_C = 10 mA and V_CE = 5.0 V, as confirmed in the Fairchild Rev. A1 datasheet. This value holds across the full operating temperature range and is binned during final test - ensuring predictable gain in high-sensitivity amplifier designs where MPSA27_D75Z is deployed.

Does MPSA27_D75Z support switching applications?

Yes, MPSA27_D75Z supports switching applications with V_CE(sat) = 1.5 V at I_C = 100 mA / I_B = 0.1 mA. Its high h_FE reduces required base drive, enabling clean saturation in relay drivers and LED switches. However, it is not optimized for high-speed PWM; for >100 kHz switching, dedicated MOSFETs or faster BJTs like BC847 are recommended over MPSA27_D75Z.

What is the thermal resistance of MPSA27_D75Z in TO-92 package?

The MPSA27_D75Z has R_θJA = 200 °C/W when mounted on a standard FR-4 PCB (36 mm × 18 mm × 1.5 mm) with a 6 cm² collector pad, per the Fairchild datasheet. Without thermal enhancement, power dissipation must stay below ~310 mW at 70 °C ambient to maintain T_J ≤ 150 °C - confirming why MPSA27_D75Z is rated for 625 mW only at 25 °C ambient.

Is MPSA27_D75Z pin-compatible with other TO-92 NPN transistors?

MPSA27_D75Z uses JEDEC-standard TO-92 pinout: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector. It is mechanically compatible with all standard TO-92 footprints, but electrical compatibility depends on h_FE, V_CEO, and V_CE(sat). Substituting generic TO-92 NPNs (e.g., 2N2222) may cause gain mismatch or saturation issues - always verify circuit performance when replacing with MPSA27_D75Z.

What is the maximum operating frequency for small-signal amplification using MPSA27_D75Z?

The MPSA27_D75Z has f_T = 125 MHz at I_C = 10 mA and V_CE = 5.0 V, meaning its usable small-signal amplification bandwidth is typically ≤ 10–20 MHz for stable, un-compensated gain >10. While f_T indicates unity-gain frequency, practical linear amplification with MPSA27_D75Z is validated up to VHF band in tuned circuits - not broadband video or GHz applications.