onsemi MPSA14

Overview

MPSA14 from onsemi is an NPN silicon Darlington transistor in TO-92 package, rated for 30 V_CE, 500 mA continuous collector current, and 625 mW power dissipation at 25°C ambient. It delivers DC current gain (h_FE) of 10,000–20,000 at I_C = 100 mA and V_CE = 5 V, with V_CE(sat) ≤ 1.5 V and V_BE(on) ≤ 2.0 V - used in low-speed switching, relay drivers, and signal amplification stages where high gain and moderate power handling are required.

For engineers reviewing the MPSA14 datasheet, pinout, applications, or equivalent options, key selection considerations include its Darlington configuration for high-current drive with minimal base drive, TO-92 mechanical compatibility, thermal derating above 25°C, and noise performance in audio preamp or sensor interface circuits.

Technical Context

The MPSA14 operates as a two-stage NPN Darlington pair, providing cascaded current gain to achieve h_FE ≥ 10,000 at 100 mA, with V_CE(sat) specified at I_C/I_B = 1000. Its junction-to-ambient thermal resistance is 200°C/mW, limiting sustained power delivery without heatsinking.

It features V_(BR)CES = 30 V, V_EBO = 10 V, and f_T = 125 MHz - indicating usable bandwidth beyond audio frequencies but optimized for DC/low-frequency switching rather than RF operation. Noise characteristics are characterized across 10 Hz–15.7 kHz bandwidth with source resistance dependence.

Key Specifications

Pinout & Package

Package: TO-92 (Case 29-11, Style 1), through-hole, Pb-free compatible, 3-pin plastic package with standardized lead spacing and mechanical dimensions per ON Semiconductor specification.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPSA13 and ULN2003A, the MPSA14 provides the highest single-transistor DC gain in TO-92 format - making it optimal for ultra-low-base-drive applications where discrete layout flexibility and thermal isolation between channels are prioritized over integration density.

Availability

MPSA14 is available at Aetrix Electronics and suitable for relay drivers, low-power motor controls, audio preamplifiers, and industrial sensor interfaces requiring stable component supply and long-term obsolescence resilience.

Supply support for MPSA14 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, and cloud infrastructure markets.

The MPSA14 belongs to onsemi's legacy general-purpose bipolar transistor family - designed specifically for cost-sensitive, high-reliability discrete switching and amplification in consumer, industrial, and telecom equipment.

FAQ

What is the maximum continuous collector current rating for the MPSA14?

The MPSA14 is rated for 500 mA continuous collector current (I_C) at T_A = 25°C. This rating decreases with rising ambient temperature due to its 5.0 mW/°C thermal derating factor. At 75°C ambient, the practical I_C limit drops to approximately 375 mA. The MPSA14 must be operated within this derated envelope to avoid thermal runaway or permanent degradation.

Is the MPSA14 pin-compatible with the MPSA13?

Yes, the MPSA14 is fully pin-compatible with the MPSA13 - both use identical TO-92 package (Case 29-11, Style 1) with Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector. No PCB layout changes are required when upgrading from MPSA13 to MPSA14, though system-level gain and saturation voltage improvements should be verified in final circuit operation.

Does the MPSA14 have built-in protection diodes?

No, the MPSA14 does not include integrated flyback or clamp diodes. When switching inductive loads such as relays or solenoids, an external reverse-biased diode (e.g., 1N4001) must be placed across the load to suppress voltage spikes during turn-off. This protection is mandatory to prevent V_CE overshoot beyond the 30 V rating and ensure long-term reliability of the MPSA14.

What is the typical DC current gain (h_FE) of the MPSA14 at 10 mA collector current?

While the MPSA14's datasheet specifies h_FE = 10,000–20,000 at I_C = 100 mA, its gain at 10 mA is not explicitly guaranteed. However, Figure 8 shows h_FE ≈ 15,000–25,000 in that region at 25°C. For designs relying on precise low-current gain, the MPSA14RLRPG should be validated under actual operating conditions - as h_FE varies significantly with temperature and current level.

Can the MPSA14 be used in linear amplifier configurations?

Yes, the MPSA14 can operate in linear (active) mode for low-frequency amplification, supported by its characterized noise voltage (Figure 2), f_T = 125 MHz, and stable h_FE over collector current. However, its Darlington structure introduces higher V_BE(on) (~2.0 V) and greater thermal sensitivity than single transistors - requiring careful biasing and thermal design to maintain stability in Class-A or AB stages using the MPSA14.