Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

onsemi MJE170

Name: MJE170
Brand: onsemi
SKU: MJE170
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: MJE170

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-225AA, TO-126-3

Datasheet:: MJE170.pdf

Description:: TRANS PNP 40V 3A TO-126

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:3,698

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

MJE170 from onsemi is a PNP silicon power transistor designed for low-power audio amplifier stages and low-current, high-speed switching applications. It features 40 V_CEO, 3.0 A continuous collector current, 12.5 W total power dissipation at T_C = 25°C, DC current gain (h_FE) of 50–250 at I_C = 100 mA, and f_T = 50 MHz - enabling use in Class-A/B output stages and driver circuits.

For engineers reviewing the MJE170 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical ratings, TO-225 package layout, thermal derating behavior, safe operating area limits, and validated alternative transistors for audio and switching designs requiring PNP complementarity with the MJE180 series.

Technical Context

The MJE170 is a discrete PNP bipolar junction transistor with annular construction to minimize leakage currents and optimized for linear amplification and fast-switching operation. Its 40 V_CEO rating and 3.0 A I_C support mid-level audio output drive, while its 50 MHz f_T enables stable gain up to several megahertz in tuned or broadband stages.

Thermal design is constrained by R_JC = 10°C/W and R_JA = 83.4°C/W, requiring heatsinking for sustained >1.5 W dissipation. Safe operating area (SOA) curves confirm second-breakdown-limited performance below 100 V_CE, with pulse handling capability dependent on duty cycle and case temperature per Figure 4 transient thermal response data.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40 Vdc - Maximum collector-emitter voltage before breakdown under open-base conditions; defines usable rail voltage headroom in amplifier output stages.
I_C (continuous)	3.0 Adc - Continuous collector current limit; sets maximum quiescent and signal swing capability in Class-A/B audio outputs.
P_D @ T_C = 25°C	12.5 W - Junction-to-case power dissipation limit; requires mechanical heatsink interface for >1.5 W ambient operation.
h_FE	50–250 - DC current gain range at I_C = 100 mA/V_CE = 1 V; supports stable bias design across production lots and temperature.
f_T	50 MHz - Current-gain-bandwidth product; ensures adequate small-signal gain margin up to ~5–10 MHz in audio preamp or driver applications.
R_JC	10°C/W - Thermal resistance from junction to case; determines minimum heatsink thermal resistance needed for target T_J < 150°C.

Pinout & Package

Package: TO-225 (Case 77-09, Style 1), plastic-encapsulated, Pb-free, UL 94 V-0 compliant. Mounting tab is electrically connected to collector.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1	Emitter	Main current exit path for PNP device; connects to ground or negative rail in common-emitter amplifier configurations.
Pins 2 & 4	Collector	Shared collector terminal via internal connection; ties to heatsink and positive supply rail in linear amplifiers or switch loads.
Pin 3	Base	Control input for current amplification; requires current-limiting resistor in fixed-bias or emitter-follower driver topologies.

Key Features

Feature	Design Value
High DC current gain	h_FE ≥ 50 at I_C = 100 mA enables stable bias without feedback networks in low-noise preamplifier stages.
High f_T	50 MHz bandwidth supports wideband audio fidelity and clean square-wave switching up to ~5 MHz in driver circuits.
Annular construction	Reduces I_CBO to ≤ 0.1 μA at 60 V_CB, minimizing thermal runaway risk in parallel-connected or thermally coupled amplifier pairs.
TO-225 mechanical robustness	14.5–16.6 mm body length and 10.6–11.1 mm width accommodate standard heatsink footprints and manual PCB assembly.

Applications

Audio Power Amplifier Output Stage	Low-Power Switching Regulator Driver
Use Scenario: Single-ended Class-A or push-pull Class-AB output stage in portable audio equipment delivering ≤2 W into 8 Ω. IC Role / Device Role / Timing Role: PNP power transistor providing current gain and voltage swing in complementary pair with NPN MJE180. Use Value: 40 V_CEO and 3.0 A I_C enable ±15 V rail operation with headroom for transient peaks; h_FE consistency ensures matched bias across channels.	Use Scenario: High-side driver in 24 V DC-DC buck converter control loop operating at ≤500 kHz. IC Role / Device Role / Timing Role: PNP switch controlling gate of N-channel MOSFET via level-shifted base drive. Use Value: 50 MHz f_T and fast turn-on/turn-off times (<100 ns) support clean PWM edge integrity; 12.5 W P_D accommodates brief conduction losses during transition.
Discrete Transistor Audio Preamp	Industrial Signal Conditioning Interface
Use Scenario: Low-noise, high-linearity voltage amplifier in microphone preamplifier or instrument input stage. IC Role / Device Role / Timing Role: Discrete PNP BJT configured as common-emitter or emitter-follower for impedance transformation and gain. Use Value: Annular construction yields low I_CBO and stable h_FE, reducing thermal drift and distortion in precision analog paths.	Use Scenario: Isolated logic-level translator interfacing 3.3 V microcontroller GPIO to 12 V industrial sensor inputs. IC Role / Device Role / Timing Role: Saturated PNP switch converting active-low MCU output to active-high 12 V signal. Use Value: V_CE(sat) ≤ 0.3 V at I_C = 500 mA ensures minimal voltage drop and power loss; TO-225 package allows direct mounting to panel metal for EMI suppression.

Audio Power Amplifier Output Stage

Low-Power Switching Regulator Driver

Use Scenario: Single-ended Class-A or push-pull Class-AB output stage in portable audio equipment delivering ≤2 W into 8 Ω.

IC Role / Device Role / Timing Role: PNP power transistor providing current gain and voltage swing in complementary pair with NPN MJE180.

Use Value: 40 V_CEO and 3.0 A I_C enable ±15 V rail operation with headroom for transient peaks; h_FE consistency ensures matched bias across channels.

Use Scenario: High-side driver in 24 V DC-DC buck converter control loop operating at ≤500 kHz.

IC Role / Device Role / Timing Role: PNP switch controlling gate of N-channel MOSFET via level-shifted base drive.

Use Value: 50 MHz f_T and fast turn-on/turn-off times (<100 ns) support clean PWM edge integrity; 12.5 W P_D accommodates brief conduction losses during transition.

Discrete Transistor Audio Preamp

Industrial Signal Conditioning Interface

Use Scenario: Low-noise, high-linearity voltage amplifier in microphone preamplifier or instrument input stage.

IC Role / Device Role / Timing Role: Discrete PNP BJT configured as common-emitter or emitter-follower for impedance transformation and gain.

Use Value: Annular construction yields low I_CBO and stable h_FE, reducing thermal drift and distortion in precision analog paths.

Use Scenario: Isolated logic-level translator interfacing 3.3 V microcontroller GPIO to 12 V industrial sensor inputs.

IC Role / Device Role / Timing Role: Saturated PNP switch converting active-low MCU output to active-high 12 V signal.

Use Value: V_CE(sat) ≤ 0.3 V at I_C = 500 mA ensures minimal voltage drop and power loss; TO-225 package allows direct mounting to panel metal for EMI suppression.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MJE171G	Higher V_CEO = 60 V, same TO-225 package and pinout; h_FE min 30 at I_C = 500 mA.	Supports higher supply rails (±24 V) but exhibits lower gain at high current; suitable where voltage margin outweighs gain stability.	Select MJE171G when system rail exceeds 30 V and SOA must extend beyond 40 V_CE.
BC557B	TO-92 package, I_C = 100 mA, V_CEO = 45 V, h_FE = 200–450 - not pin-compatible and lacks power handling.	Only viable for signal-level preamp use; cannot replace MJE170 in output or driver roles due to 1.5 W P_D limit.	Use BC557B only in low-current bias or sensing circuits - never as functional substitute in power stages.

Compared with MJE171G, the MJE170 offers tighter h_FE tolerance at low current and better thermal coupling in TO-225 heatsink mounts, while BC557B serves only non-power signal functions and requires full circuit redesign for substitution.

Availability

MJE170 is available at Aetrix Electronics and suitable for low-power audio amplifier output stages, industrial signal conditioning interfaces, and low-current switching regulator drivers requiring stable component supply and RoHS-compliant packaging.

Supply support for MJE170 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, sensors, and connectivity solutions for automotive, industrial, and consumer markets.

The MJE170 belongs to onsemi's complementary silicon power transistor family engineered for reliable linear amplification and switching in cost-sensitive, thermally constrained applications where TO-225 packaging and Pb-free compliance are required.

FAQ

What is the maximum collector-emitter voltage rating for the MJE170?

The MJE170 has a maximum collector-emitter sustaining voltage (V_CEO(sus)) of 40 Vdc at I_C = 10 mA and I_B = 0. This rating defines the absolute upper limit for voltage applied between collector and emitter with the base open, and must not be exceeded to avoid avalanche breakdown or permanent damage to the MJE170.

Does the MJE170 have a built-in heatsink tab, and how is it electrically isolated?

Yes, the MJE170 in TO-225 package features a metal mounting tab that is internally connected to the collector terminal. It is not electrically isolated - users must ensure proper insulation (e.g., mica washer + thermal paste) when mounting to grounded heatsinks. The tab's direct collector tie simplifies thermal path but mandates isolation in common-collector or high-side switch configurations.

What is the typical DC current gain (h_FE) of the MJE170 at different operating points?

The MJE170 specifies h_FE = 50–250 at I_C = 100 mA and V_CE = 1.0 Vdc; 30–250 at I_C = 500 mA; and 12–250 at I_C = 1.5 A. These ranges reflect production variation and current-dependent degradation - design margins should assume minimum h_FE = 50 for I_C ≤ 200 mA to ensure stable MJE170 bias under worst-case conditions.

Can the MJE170 be used in parallel with other transistors for higher current handling?

Parallel operation of the MJE170 is not recommended without individual emitter resistors and matched devices, due to positive thermal feedback and h_FE variation across lots. The annular construction reduces leakage mismatch, but SOA derating and thermal coupling require careful layout. For >3 A applications, consider dedicated high-current devices rather than paralleling multiple MJE170 units.

Is the MJE170 RoHS-compliant and lead-free?

Yes, the MJE170G suffix denotes a Pb-free, RoHS-compliant version per onsemi documentation. The epoxy meets UL 94 V-0 flammability rating at 0.125 inch thickness, and all plating and die attach materials conform to EU Directive 2011/65/EU. No lead content is present in the finished MJE170G device or its TO-225 package.

MJE170 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-225AA, TO-126-3

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: PNP

Current - Collector (Ic) (Max):: 3 A

Voltage - Collector Emitter Breakdown (Max):: 40 V

Vce Saturation (Max) @ Ib, Ic:: 1.7V @ 600mA, 3A

Current - Collector Cutoff (Max):: 100nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 50 @ 100mA, 1V

Power - Max:: 12.5 W

Frequency - Transition:: 50MHz

Operating Temperature:: -65°C ~ 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-126

MJE170 FAQ

1.How can I place an order for MJE170 through Aetrix?

Please submit a Request for Quotation (RFQ) for MJE170 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 MJE170 reliable?

The price and inventory of MJE170 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MJE170 is usually 5 days.

3.What payment methods are accepted for MJE170?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MJE170 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MJE170?

MJE170 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MJE170 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 MJE170?

For technical support, including MJE170 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MJE170 requirements.

6.How does Aetrix verify that MJE170 is sourced from the original manufacturer or authorized distributors?

All MJE170 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 MJE170 meets industry standards.

7.What is the process for return or replacement of MJE170?

All MJE170 units undergo pre-shipment inspection (PSI). If there is an issue with MJE170, 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 MJE170 part is unused and in its original packaging.

Return procedure for MJE170:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-09 Counterfeit Electronic Components: How to Detect, Authenticate, and Test Suspect Parts

Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…