onsemi MJH11021

Summary of onsemi MJH11021 PNP Darlington Power Transistor

The onsemi MJH11021 is a high-power PNP Darlington bipolar junction transistor (BJT), engineered for demanding applications such as low-frequency switching, motor control, and general-purpose high-current amplification. With its maximum collector-emitter voltage rating of 250 V and continuous collector current of 15 A, the MJH11021 is designed to deliver solid-state reliability in industrial and power electronics circuits. This device, presented in either SOT-93 (TO-218) or TO-247 through-hole packages, is part of onsemi’s established MJH110xx complementary Darlington series, offering solutions for both PNP and NPN requirements.

onsemi MJH11021 key features and performance

summary

The MJH11021 distinguishes itself with several critical features attractive to both circuit designers and procurement professionals:

High DC current gain: With a minimum hFE of 400 at 10 A collector current, the MJH11021 supports robust signal amplification and efficient switching control.

High voltage capability: Its 250 V collector-emitter breakdown voltage maximizes flexibility for a wide variety of industrial and high-power applications.

Power dissipation: The device can handle up to 150 W (Tc = 25°C), advantageous for heat-intensive and high-output environments.

Low collector-emitter saturation voltage: Typical VCE(sat) values of 1.2 V (@ 5 A) and 1.8 V (@ 10 A) aid efficiency by minimizing power loss during conduction.

Monolithic Darlington construction: The MJH11021 ensures reliable, high-gain, and high-speed operation through an integrated two-transistor arrangement.

RoHS status: While the device is RoHS non-compliant, it is listed as REACH unaffected and features high reliability for legacy and industrial systems.

Maximum ratings and thermal management for onsemi MJH11021

For power transistors like the MJH11021, understanding and adhering to the absolute maximum ratings is fundamental for reliable design. Key limits include:

Collector-emitter voltage (VCEO): 250 V

Collector current (continuous): 15 A; peak, non-repetitive: 30 A

Base current: 0.5 A

Power dissipation: 150 W at 25°C case temperature, with a derating factor of 1.2 W/°C above 25°C

Operating and storage junction temperature: -65°C to +150°C

Thermal resistance from junction to case is a low 0.83°C/W, supporting effective heat transfer when using appropriate heatsinking. Engineers must carefully design for junction temperature limits, especially under conditions with high switching frequencies or in confined mechanical layouts. Power derating curves further inform safe operating margins as the case temperature rises.

Electrical characteristics of onsemi MJH11021

Delving into the electrical parameters, the MJH11021 offers:

Collector-emitter sustaining voltage (VCEO(sus)): 250 V (minimum)

Collector cutoff current (ICEO): ≤1.0 mA at VCE = 125 V, IB = 0

Emitter cutoff current (IEBO): ≤2.0 mA at VBE = 5 V

DC current gain (hFE): Ranges from 100 (at 15 A) to 400 (at 10 A, VCE = 5 V)

Collector-emitter saturation voltage (VCE(sat)): Maximum 4.0 V at 15 A, 150 mA base current

Base-emitter on voltage: Maximum 2.8 V at 10 A, VCE = 5 V

These parameters confirm the suitability of the MJH11021 for high-current, low-saturation switching and provide clear thresholds for biasing and control.

Switching and dynamic performance of the onsemi MJH11021

Switching speed and frequency characteristics influence suitability in motor drives and switching regulators. Key dynamic figures for the MJH11021 include:

Transition frequency (fT): 3 MHz (IC = 10 A, VCE = 3 V, f = 1 MHz)

Small-signal current gain (hfe): >75 under specified test conditions

Delay time: 75 ns; rise time: 0.5 μs; storage time: 2.7 μs; fall time: 2.5 μs (PNP type values, VCC = 100 V, IC = 10 A)

Output capacitance: Up to 600 pF

These switching specifications enable the device to operate efficiently at moderate switching frequencies typical in industrial automation or power supplies. However, designers should also consider driver capabilities and snubbing requirements for optimal switching transitions.

Safe operating area and practical design considerations with MJH11021

The MJH11021’s safe operating area (SOA) curves provide crucial guidance for system designers, outlining the permissible combinations of current and voltage for both forward and reverse bias conditions. Devices such as the MJH11021 must not exceed these boundaries to avoid phenomena like second breakdown or thermal runaway, especially during load switching or fault conditions.

Forward bias safe operating area (FBSOA): Defines Ic-VCE limits; valid up to TJ(pk) = 150°C with specified duty cycles.

Reverse bias safe operating area (RBSOA): Important for inductive loads and during turn-off; reverse base-emitter voltages must stay within recommended ranges.

Protective measures such as active clamping, RC snubbing, or careful load line shaping are often recommended for designs utilizing the MJH11021.

Package information and mechanical data for the MJH11021

Mechanical compatibility and layout influence the ease of prototyping and final assembly. The MJH11021 PNP Darlington transistor is supplied in SOT-93 (TO-218) and TO-247 packages, both proven standards for power semiconductors:

SOT-93 dimensions: 20.35 mm length (min), 14.70–15.20 mm width; 3-lead through-hole mounting.

TO-247 dimensions: 20.32–21.08 mm length, 15.75–16.26 mm width.

Both packages ensure reliable PCB attachment and thermal transfer when paired with suitable heatsinks. Pin assignments follow industry conventions (1 – base, 2 – collector, 3 – emitter), streamlining replacement and cross-compatibility.

Potential equivalent/replacement models for onsemi MJH11021

Due to its obsolete status, sourcing alternatives or equivalents for the MJH11021 is important for new designs or maintenance in legacy systems. Direct alternatives within the onsemi MJH110xx family include:

NPN complements: MJH11018, MJH11020, MJH11022

Other high-voltage PNP Darlington transistors rated for similar maximum collector-emitter voltages (250 V), continuous collector currents (15 A), and power dissipation (150 W) can also be considered. When selecting a replacement, ensure parameters such as VCE(sat), fT, current gain, and package type match the requirements of your application.

Engineers must verify SOA, switching characteristics, and thermal management needs before finalizing a substitute device.

Conclusion

The onsemi MJH11021 PNP Darlington power transistor stands as a robust solution for high-current, high-voltage power switching and amplification tasks. Its high current gain, power dissipation capability, and stringent safe operating characteristics make it a valuable choice for industrial and motor control applications. However, given its obsolete status, engineers must consider availability and equivalent options to ensure long-term support and maintainability in their designs. Accurate understanding of its ratings, switching behavior, and package details will guide optimal circuit integration and reliable system operation.