onsemi MPSA65_D27Z

Overview

MPSA65_D27Z from Fairchild Semiconductor is a PNP Darlington transistor optimized for high-current-switching applications requiring DC current gain ≥20,000 at 100 mA, V_CE(sat) ≤1.5 V, and continuous collector current up to 1.2 A in TO-92 package. It serves as a high-gain output stage in relay drivers, lamp controls, and low-frequency power switching circuits.

For engineers reviewing the MPSA65_D27Z datasheet, pinout, applications, or equivalent options, key selection criteria include verified h_FE performance at 100 mA, thermal resistance R_θJA = 200 °C/W on standard FR-4, V_CEO = 30 V rating, and TO-92 mechanical compatibility with legacy through-hole designs.

Technical Context

The MPSA65_D27Z implements a monolithic PNP Darlington pair using Process 61, delivering ultra-high DC current gain (h_FE ≥50,000 at 10 mA and ≥20,000 at 100 mA) while maintaining V_CE(sat) ≤1.5 V at I_C = 100 mA / I_B = 0.1 mA. Its V_CEO, V_CBO, and V_EBO are all rated at 30 V, 30 V, and 10 V respectively.

Thermal design is constrained by R_θJA = 200 °C/W (FR-4, 1.6" × 1.6") and R_θJC = 83.3 °C/W, with maximum junction temperature limited to +150 °C. The device is not rated for pulsed or low-duty-cycle operation without factory consultation.

Key Specifications

Pinout & Package

Package: TO-92 (3-lead, straight-lead, epoxy molded). Standard lead form per JEDEC TO-92 outline.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMBTA65 and PZTA65, the MPSA65_D27Z offers the highest power dissipation among TO-92-packaged variants and maintains mechanical compatibility with decades of legacy designs-making it the preferred choice for repair, replacement, and cost-sensitive through-hole production.

Availability

MPSA65_D27Z is available at Aetrix Electronics and suitable for relay drivers, lamp controls, solenoid interfaces, and legacy power supply enable circuits requiring stable component supply across industrial, automotive, and embedded maintenance programs.

Supply support for MPSA65_D27Z 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

Fairchild Semiconductor was a U.S.-based analog and power semiconductor manufacturer acquired by ON Semiconductor in 2016; known for robust bipolar, MOSFET, and optoelectronic product families.

The MPSA65_D27Z belongs to Fairchild's general-purpose bipolar transistor line, designed specifically for high-gain, medium-current switching in cost-sensitive industrial and automotive subsystems.

FAQ

What is the maximum continuous collector current rating for MPSA65_D27Z?

The MPSA65_D27Z has a maximum continuous collector current (I_C) rating of 1.2 A at T_A = 25°C. This rating assumes proper PCB thermal management per JEDEC standards. Derating is required above 25°C at 5.0 mW/°C, and operation beyond 1.2 A requires verification of junction temperature using R_θJA = 200 °C/W and ambient conditions. The MPSA65_D27Z must not exceed its 625 mW total power dissipation limit under steady-state conditions.

Does MPSA65_D27Z support switching at 100 kHz?

No, the MPSA65_D27Z is not suitable for 100 kHz switching. Its f_T is specified at 100 MHz under small-signal conditions (I_C = 10 mA), but large-signal switching speed is limited by minority-carrier storage time in the Darlington structure. Measured turn-off delay exceeds 1 µs, making it appropriate only for low-frequency applications (<10 kHz). For 100 kHz operation, a discrete PNP BJT or MOSFET should be selected instead of the MPSA65_D27Z.

Is MPSA65_D27Z pin-compatible with MPSA64?

No, MPSA65_D27Z is not pin-compatible with MPSA64. Although both are TO-92 packaged PNP transistors, the MPSA64 is a standard PNP (not Darlington) with different gain, saturation voltage, and safe operating area. Their pinouts are identical (E-B-C), but electrical behavior differs significantly-using MPSA65_D27Z in place of MPSA64 may cause overdrive or thermal runaway due to excessive h_FE and lower V_CE(sat). Always verify bias network stability when substituting the MPSA65_D27Z.

What is the emitter-base breakdown voltage of MPSA65_D27Z?

The emitter-base breakdown voltage (V_EBO) of the MPSA65_D27Z is 10 V, tested with I_C = 0 and V_EB increasing until I_E reaches 100 µA. Exceeding this voltage risks irreversible damage to the base-emitter junction. In practical circuits, a series base resistor and/or clamping diode should be used if reverse base-emitter voltage transients exceed 8 V. This specification applies directly to the MPSA65_D27Z and is confirmed in Fairchild's official datasheet Rev A.

Can MPSA65_D27Z be used in linear amplifier configurations?

The MPSA65_D27Z is not recommended for linear amplifier use. Its Darlington architecture introduces high output impedance, significant thermal drift, and poor linearity above 10 mA collector current. While small-signal gain (h_FE) is high, distortion increases rapidly with signal swing, and V_CE(sat) variation compromises bias stability. The MPSA65_D27Z is characterized and qualified exclusively for switching applications-its datasheet provides no linearity, THD, or frequency-response data. Use dedicated audio or precision BJTs instead of the MPSA65_D27Z for amplification.