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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

onsemi MPSA44RL1

Name: MPSA44RL1
Brand: onsemi
SKU: MPSA44RL1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MPSA44RL1

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 Long Body, Formed Leads

Datasheet:: MPSA44RL1.pdf

Description:: TRANS NPN 400V 0.3A TO92

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MPSA44RL1 from onsemi is an NPN silicon high-voltage general-purpose transistor rated for 400 V_CEO, 500 V_CBO, and 300 mA continuous collector current in a TO-92 package. It delivers DC current gain (h_FE) of 40–200 across 1–100 mA, with V_CE(sat) ≤ 0.75 V at I_C/I_B = 10, and supports switching applications up to 20 MHz small-signal gain bandwidth.

For engineers reviewing the MPSA44RL1 datasheet, pinout, applications, or equivalent options, key selection criteria include high-voltage blocking capability, TO-92 thermal performance (R_θJA = 200°C/W), safe operating area limits at 150 V, and verified h_FE stability across −55°C to +150°C junction temperature range.

Technical Context

The MPSA44RL1 operates as a medium-speed, high-voltage NPN switch with validated saturation behavior at I_C = 100 mA and I_B = 10 mA, and exhibits C_obo = 7.0 pF and C_ibo = 130 pF at 1 MHz under specified bias conditions. Its safe operating area is defined by thermal, current, and second-breakdown limits up to 100 ms pulse width at T_A = 25°C.

It features low leakage: I_CBO ≤ 0.1 A at V_CB = 400 V and I_CES ≤ 500 nA at V_CE = 400 V, and maintains V_BE(sat) ≤ 0.75 V at I_C/I_B = 10. Switching times (t_r, t_f, t_d, t_s) are characterized at V_CC = 150 V with 2% duty cycle pulses.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	400 V - Supports switching loads up to 400 V without breakdown under open-base conditions.
I_C (continuous)	300 mA - Sustains steady-state collector current sufficient for relay drivers and HV logic interfaces.
h_FE @ 10 mA	50–200 - Enables reliable base drive design for linear amplification or saturated switching with margin.
V_CE(sat) @ 50 mA	≤ 0.75 V - Minimizes conduction loss and self-heating in power-switching configurations.
R_θJA	200°C/W - Defines maximum junction-to-ambient thermal resistance in still-air TO-92 mounting.
f_T	20 MHz - Confirmed small-signal current gain bandwidth for moderate-frequency switching.
T_J range	−55°C to +150°C - Validated operation across industrial and automotive under-hood ambient extremes.

Pinout & Package

Package: TO-92 (Case 29-11, Style 1), epoxy-molded, through-hole compatible, Pb-free option available (MPSA44RL1G). Dimensions per ANSI Y14.5M; lead pitch 2.54 mm.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current exit path for NPN transistor	Connected to ground or low-side return; defines reference for V_BE and V_CE biasing.
2 (Base)	Control terminal for minority-carrier injection	Receives current-limited drive to saturate or cut off the device; requires external series resistor for protection.
3 (Collector)	High-voltage current input node	Interfaces with load or supply rail up to 400 V; thermally coupled to case for R_θJC = 83.3°C/W.

Key Features

Feature	Design Value
High V_CBO rating	500 V - Enables use in flyback snubbers and HV line-sensing circuits where collector-base stress exceeds 400 V.
Low I_CES leakage	≤ 500 nA at V_CE = 400 V - Ensures stable off-state integrity in high-impedance sample-and-hold or HV standby paths.
Verified SOA at 150 V	Validated up to 100 ms pulses - Supports energy-limited transient switching in relay coil suppression and capacitor discharge circuits.
Pb-free packaging option	MPSA44RL1G variant available - Meets RoHS Directive 2011/65/EU and JEDEC J-STD-609A Class 1 moisture sensitivity.
Wide temperature operation	Functional from −55°C to +150°C - Qualified for industrial control modules and automotive non-critical subsystems.

Applications

Relay Driver Circuits	High-Voltage Logic Interface
Use Scenario: Driving 12–24 VDC relays with coil inductance >100 mH in programmable logic controllers. IC Role / Device Role / Timing Role: NPN switch controlling relay coil current; handles inductive kickback via V_CBO margin and SOA compliance. Use Value: Eliminates need for external clamping diodes in many designs due to 500 V_CBO and robust second-breakdown immunity.	Use Scenario: Level-shifting TTL/CMOS signals to interface with 100–300 V DC bus monitoring circuits. IC Role / Device Role / Timing Role: High-side or low-side level translator with galvanic isolation support via optocoupler coupling. Use Value: Maintains signal integrity with <10 ns turn-off delay at 150 V, enabling real-time fault detection in power supplies.
Flyback Converter Snubber	Capacitor Discharge Circuit
Use Scenario: Absorbing leakage inductance energy in offline AC-DC flyback converters operating at 65–100 kHz. IC Role / Device Role / Timing Role: Active clamp transistor in RCD snubber network; conducts during MOSFET off-time. Use Value: Withstands repetitive 400 V reverse bias and dissipates <1 W peak during clamp events without derating.	Use Scenario: Controlled discharge of high-voltage storage capacitors (e.g., 350 V, 100 µF) in medical imaging power supplies. IC Role / Device Role / Timing Role: Precision-timed discharge switch triggered by microcontroller GPIO. Use Value: Delivers predictable 50–100 mA discharge current with <0.5 V drop, minimizing residual voltage error.

Relay Driver Circuits

High-Voltage Logic Interface

Use Scenario: Driving 12–24 VDC relays with coil inductance >100 mH in programmable logic controllers.

IC Role / Device Role / Timing Role: NPN switch controlling relay coil current; handles inductive kickback via V_CBO margin and SOA compliance.

Use Value: Eliminates need for external clamping diodes in many designs due to 500 V_CBO and robust second-breakdown immunity.

Use Scenario: Level-shifting TTL/CMOS signals to interface with 100–300 V DC bus monitoring circuits.

IC Role / Device Role / Timing Role: High-side or low-side level translator with galvanic isolation support via optocoupler coupling.

Use Value: Maintains signal integrity with <10 ns turn-off delay at 150 V, enabling real-time fault detection in power supplies.

Flyback Converter Snubber

Capacitor Discharge Circuit

Use Scenario: Absorbing leakage inductance energy in offline AC-DC flyback converters operating at 65–100 kHz.

IC Role / Device Role / Timing Role: Active clamp transistor in RCD snubber network; conducts during MOSFET off-time.

Use Value: Withstands repetitive 400 V reverse bias and dissipates <1 W peak during clamp events without derating.

Use Scenario: Controlled discharge of high-voltage storage capacitors (e.g., 350 V, 100 µF) in medical imaging power supplies.

IC Role / Device Role / Timing Role: Precision-timed discharge switch triggered by microcontroller GPIO.

Use Value: Delivers predictable 50–100 mA discharge current with <0.5 V drop, minimizing residual voltage error.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MPSA42RL1	V_CEO = 300 V (lower), h_FE min = 25 @ 10 mA (lower gain), same TO-92 package	Limited to ≤300 V systems; less margin for surge transients and inductive spikes	Select when cost sensitivity outweighs 100 V headroom requirement and lower gain is acceptable.
BC639	V_CEO = 80 V (much lower), I_C = 1 A (higher), h_FE = 40–250, TO-92 package	Not suitable for >100 V applications; better for high-current, low-voltage motor drivers	Choose only for sub-80 V DC loads where higher current capacity is critical and voltage margin is irrelevant.

Compared with MPSA44RL1, MPSA42RL1 trades 100 V blocking headroom for slightly lower cost, while BC639 offers higher current but fails to meet basic 400 V requirements-making MPSA44RL1 the sole viable choice for 300–400 V switching nodes.

Availability

MPSA44RL1 is available at Aetrix Electronics and suitable for relay driver circuits, high-voltage logic interfaces, and flyback converter snubbers requiring stable component supply, consistent TO-92 tape-and-reel delivery, and long-term industrial lifecycle support.

Supply support for MPSA44RL1 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, cloud, and consumer markets.

The MPSA44RL1 belongs to onsemi's legacy high-voltage bipolar transistor product line, designed specifically for industrial control, power supply protection, and HV signal conditioning where reliability at elevated voltage stress is mandatory.

FAQ

What is the maximum continuous collector current rating for MPSA44RL1?

The MPSA44RL1 is rated for 300 mA continuous collector current (I_C) at T_A = 25°C. Derating applies above 25°C at 5.0 mW/°C for free-air operation. At T_C = 25°C, it supports 1.5 W total dissipation with 12 mW/°C derating. Actual usable current depends on PCB layout, heatsinking, and ambient conditions-designers must validate thermal performance per application.

Does MPSA44RL1 have Pb-free packaging options?

Yes, the MPSA44RL1G variant is the Pb-free version of MPSA44RL1, compliant with RoHS Directive 2011/65/EU and JEDEC J-STD-609A Class 1 moisture sensitivity. Both MPSA44RL1 and MPSA44RL1G use identical TO-92 mechanical dimensions and electrical specifications-the only difference is lead finish composition.

What is the safe operating area (SOA) limit for MPSA44RL1 at 150 V?

The MPSA44RL1 SOA is validated up to 150 V with pulse widths ≤100 ms and duty cycle ≤10%, per Figure 4 in the official datasheet. At 150 V, the device supports up to ~200 mA for 10 ms pulses before entering second-breakdown region. Continuous DC operation at 150 V is not permitted-only pulsed use within SOA boundaries is guaranteed.

Can MPSA44RL1 replace MPSA42RL1 in a 400 V circuit?

No-MPSA42RL1 has V_CEO = 300 V and V_CBO = 400 V, making it unsuitable for sustained 400 V operation. The MPSA44RL1 is specifically rated for 400 V_CEO and 500 V_CBO, providing essential margin against transients and leakage in high-voltage switching nodes where MPSA42RL1 would risk premature breakdown.

What is the typical input capacitance (C_ibo) of MPSA44RL1 and how does it affect high-frequency use?

The MPSA44RL1 exhibits C_ibo = 130 pF at V_EB = 0.5 V and f = 1 MHz. This relatively high input capacitance limits its usefulness above ~20 MHz and increases base drive current requirements in fast-switching applications. For >50 MHz designs, RF-optimized transistors with C_ibo < 10 pF are recommended instead of MPSA44RL1.

MPSA44RL1 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 Long Body, Formed Leads

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 300 mA

Voltage - Collector Emitter Breakdown (Max):: 400 V

Vce Saturation (Max) @ Ib, Ic:: 750mV @ 5mA, 50mA

Current - Collector Cutoff (Max):: 500nA

DC Current Gain (hFE) (Min) @ Ic, Vce:: 50 @ 10mA, 10V

Power - Max:: 625 mW

Frequency - Transition:: -

Operating Temperature:: -55°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92 (TO-226)

MPSA44RL1 FAQ

1.How can I place an order for MPSA44RL1 through Aetrix?

Please submit a Request for Quotation (RFQ) for MPSA44RL1 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for MPSA44RL1 reliable?

The price and inventory of MPSA44RL1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MPSA44RL1 is usually 5 days.

3.What payment methods are accepted for MPSA44RL1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MPSA44RL1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MPSA44RL1?

MPSA44RL1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MPSA44RL1 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for MPSA44RL1?

For technical support, including MPSA44RL1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MPSA44RL1 requirements.

6.How does Aetrix verify that MPSA44RL1 is sourced from the original manufacturer or authorized distributors?

All MPSA44RL1 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MPSA44RL1 meets industry standards.

7.What is the process for return or replacement of MPSA44RL1?

All MPSA44RL1 units undergo pre-shipment inspection (PSI). If there is an issue with MPSA44RL1, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The MPSA44RL1 part is unused and in its original packaging.

Return procedure for MPSA44RL1:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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