onsemi MPSA43ZL1G

Overview

MPSA43ZL1G from onsemi is an NPN silicon high-voltage general-purpose transistor in TO-92 package, rated for V_CEO = 200 V, I_C = 500 mA, and P_D = 625 mW at T_A = 25°C. It delivers h_FE ≥ 40 at I_C = 10 mA and V_CE = 10 V, with V_CE(sat) ≤ 0.4 V at I_C/I_B = 10, and is used in high-voltage switching and linear amplification circuits such as flyback snubbers and relay drivers.

For engineers reviewing the MPSA43ZL1G datasheet, pinout, applications, or equivalent options, key selection criteria include its 200 V V_CEO, TO-92 mechanical compatibility, DC current gain stability across −55°C to +125°C, and low saturation voltage under moderate drive conditions.

Technical Context

The MPSA43ZL1G operates as a discrete NPN bipolar junction transistor optimized for high-voltage switching where collector-emitter breakdown exceeds 180 V and safe operating area supports pulsed loads up to 10 ms at 200 V. Its f_T = 50 MHz enables use in medium-frequency amplification and oscillator stages.

It features V_BREBO = 6.0 V, C_cb = 4.0 pF at V_CB = 20 V, and thermal resistance R_JA = 200°C/W, indicating suitability for ambient-limited through-hole applications without forced airflow or heatsinking.

Key Specifications

Pinout & Package

Package: TO-92 (Case 29−11), Pb-free, straight-lead configuration. Dimensions per ON Semiconductor specification: A = 4.45–5.20 mm, B = 4.32–5.33 mm, C = 3.18–4.19 mm.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage NPN transistor applications.

Compared with MPSA43RL1G, MPSA43ZL1G offers identical performance in a different packaging format-no electrical trade-offs. Versus BC639, MPSA43ZL1G provides 2.5× higher voltage rating and lower junction capacitance, making it irreplaceable in 200 V-class snubber and HV amplifier roles.

Availability

MPSA43ZL1G is available at Aetrix Electronics and suitable for industrial relay drivers, flyback converter snubbers, high-voltage linear amplifiers, and LED current regulators requiring stable component supply and long-term manufacturability.

Supply support for MPSA43ZL1G 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 delivering energy-efficient power, analog, sensing, and connectivity solutions for automotive, industrial, cloud, medical, and IoT applications.

The MPSA42/MPSA43 family was designed specifically for high-voltage discrete switching and amplification in cost-sensitive, reliability-critical through-hole applications including power conversion, industrial controls, and legacy equipment repair.

FAQ

What is the maximum collector-emitter voltage rating for MPSA43ZL1G?

The MPSA43ZL1G has a guaranteed minimum V_CEO of 200 VDC under test condition I_C = 1.0 mA and I_B = 0. This rating defines the absolute upper limit for collector-to-emitter potential before avalanche breakdown occurs. Designers must maintain at least 20% derating margin (i.e., ≤160 V) in continuous operation to ensure long-term reliability and thermal stability. The MPSA43ZL1G datasheet confirms this value in both Absolute Maximum Ratings and OFF Characteristics tables.

Does MPSA43ZL1G support operation at elevated temperatures?

Yes, the MPSA43ZL1G is specified for junction temperatures from −55°C to +150°C. Its h_FE remains ≥40 at I_C = 10 mA and V_CE = 10 V across this full range, and V_CE(sat) increases only modestly (to ≤0.55 V at +125°C). Thermal resistance R_JA = 200°C/W means that at 25°C ambient and 500 mA I_C, junction temperature rises ~100°C - confirming the need for layout-aware thermal design. The MPSA43ZL1G is qualified for industrial-grade thermal cycling per onsemi standards.

How does the pinout of MPSA43ZL1G differ between straight-lead and bent-lead TO-92 variants?

The MPSA43ZL1G uses the straight-lead TO-92 configuration: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector - matching the standard TO-92 pinout orientation shown in Figure 6 of the official datasheet. Bent-lead versions (e.g., MPSA43G) retain identical internal pin mapping but require different board footprint hole spacing and insertion tooling. No electrical or functional difference exists between lead forms; the MPSA43ZL1G's marking diagram and package dimensions confirm straight-lead compliance per Case 29−11.

Can MPSA43ZL1G replace MPSA42 in existing designs?

No - MPSA43ZL1G is not a drop-in replacement for MPSA42. While both share TO-92 packaging and similar h_FE, the MPSA42 has V_CEO = 300 V and V_CE(sat) ≤ 0.5 V, whereas MPSA43ZL1G is rated at V_CEO = 200 V and V_CE(sat) ≤ 0.4 V. Substituting MPSA43ZL1G into a 300 V circuit risks premature breakdown. The MPSA43ZL1G datasheet explicitly lists separate V(BR)_CEO values and warns against interchange without validation.

What is the typical transition frequency (f_T) of MPSA43ZL1G and how is it measured?

The MPSA43ZL1G has a typical f_T of 50 MHz, measured under conditions I_C = 10 mA, V_CE = 20 V, and f = 100 MHz per the Small-Signal Characteristics table. This parameter reflects the frequency at which short-circuit current gain drops to unity and indicates usable bandwidth for small-signal amplification. The MPSA43ZL1G's f_T is validated across production lots and correlates with its 4.0 pF C_cb and low base resistance - enabling stable operation in oscillator and RF detector circuits up to ~10 MHz.