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

onsemi MPSA20_D74Z

Name: MPSA20_D74Z
Brand: onsemi
SKU: MPSA20_D74Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MPSA20_D74Z

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Datasheet:: MPSA20_D74Z.pdf

Description:: TRANS NPN 40V 0.1A TO-92-3

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Product details

Overview

MPSA20_D74Z from ON Semiconductor (formerly Fairchild) is an NPN general-purpose amplifier transistor in TO-92 package, rated for 40 V V_CEO, 100 mA I_C, and 125 MHz f_T, commonly used in low-power audio preamplification, signal switching, and interface buffering stages.

For engineers reviewing the MPSA20_D74Z datasheet, pinout, applications, or equivalent options, key selection criteria include DC current gain range (h_FE = 40–400), V_CE(sat) ≤ 0.25 V at I_C = 10 mA/I_B = 1 mA, thermal resistance R_θJA = 200 °C/W, and compatibility with FR-4 PCB mounting per JEDEC TO-92 footprint.

Technical Context

The MPSA20_D74Z operates as a silicon NPN bipolar junction transistor optimized for linear amplification and low-speed switching. Its h_FE variation across I_C = 0.1–10 mA and V_CE = 10 V enables stable biasing in Class-A small-signal stages, while its 4.0 pF C_ob supports bandwidth-critical designs up to ~125 MHz.

Thermal design relies on its 200 °C/W junction-to-ambient resistance under standard FR-4 mounting (36 mm × 18 mm × 1.5 mm board, 6 cm² collector pad). The device is not rated for life-support applications and requires derating above 25°C at 5.0 mW/°C.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	40 V - Maximum safe collector-emitter voltage before breakdown; defines rail headroom in amplifier or switch circuits.
I_C (continuous)	100 mA - Absolute max DC collector current; usable up to ~50 mA for reliable thermal margin on standard PCB.
h_FE	40–400 - Wide DC current gain range at I_C = 5 mA/V_CE = 10 V; impacts bias stability and stage gain predictability.
f_T	125 MHz - Unity-gain frequency; sets upper limit for small-signal amplification bandwidth in common-emitter configuration.
V_CE(sat)	0.25 V @ I_C=10 mA/I_B=1 mA - Low saturation voltage enables efficient switching in logic-level interfaces and relay drivers.
R_θJA	200 °C/W - Junction-to-ambient thermal resistance on FR-4; determines temperature rise under 625 mW P_D at 25°C ambient.

Pinout & Package

TO-92 plastic package with 3-pin vertical lead configuration: 1. Emitter, 2. Base, 3. Collector. Standard JEDEC TO-92 outline with 1.27 mm lead pitch and 14.47 mm body length.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Reference node for bias network; connects to ground or emitter resistor in common-emitter amplifier.
2 (Base)	Control input	Receives base drive current to modulate collector current; requires current-limiting resistor in most configurations.
3 (Collector)	Output current source	Delivers amplified output current; mounted on ≥6 cm² copper pad for thermal management per datasheet recommendation.

Key Features

Feature	Design Value
High f_T	125 MHz - Enables RF-capable amplification up to VHF band in low-noise receiver front-ends.
Low V_CE(sat)	≤0.25 V - Reduces conduction loss in switching applications, improving efficiency in discrete logic translators.
Wide h_FE range	40–400 - Accommodates production spread without circuit redesign; simplifies binning in cost-sensitive consumer electronics.
JEDEC TO-92 compliance	Standardized footprint - Ensures mechanical interchangeability with MPSA18, MPSA13, and other TO-92 NPN transistors.

Applications

Audio Preamp Stage	Logic Level Translator
Use Scenario: Amplifying microphone or sensor signals prior to ADC sampling in portable audio recorders. IC Role / Device Role / Timing Role: NPN small-signal amplifier in common-emitter configuration with emitter degeneration. Use Value: 125 MHz f_T and 40–400 h_FE ensure flat 20 Hz–20 kHz response with minimal distortion at low supply voltages.	Use Scenario: Converting 3.3 V CMOS logic outputs to drive 5 V TTL inputs in mixed-voltage microcontroller systems. IC Role / Device Role / Timing Role: Discrete level-shifting switch with base resistor bias network. Use Value: V_CE(sat) ≤ 0.25 V ensures clean low-state definition, while 40 V V_CEO provides margin against transient overshoot.
Relay Driver Circuit	Signal Buffer for Sensor Interface
Use Scenario: Driving 12 V, 40 mA coil relays from microcontroller GPIO pins in industrial control panels. IC Role / Device Role / Timing Role: Saturated switch with base current limiting and flyback diode protection. Use Value: 100 mA I_C rating and 0.25 V V_CE(sat) minimize power dissipation and heat buildup during continuous operation.	Use Scenario: Isolating and buffering analog output from thermistor or potentiometer networks in HVAC control units. IC Role / Device Role / Timing Role: Unity-gain emitter-follower buffer to prevent loading of high-impedance sensor sources. Use Value: High h_FE (up to 400) ensures low output impedance (<50 Ω) and minimal signal attenuation across temperature.

Audio Preamp Stage

Logic Level Translator

Use Scenario: Amplifying microphone or sensor signals prior to ADC sampling in portable audio recorders.

IC Role / Device Role / Timing Role: NPN small-signal amplifier in common-emitter configuration with emitter degeneration.

Use Value: 125 MHz f_T and 40–400 h_FE ensure flat 20 Hz–20 kHz response with minimal distortion at low supply voltages.

Use Scenario: Converting 3.3 V CMOS logic outputs to drive 5 V TTL inputs in mixed-voltage microcontroller systems.

IC Role / Device Role / Timing Role: Discrete level-shifting switch with base resistor bias network.

Use Value: V_CE(sat) ≤ 0.25 V ensures clean low-state definition, while 40 V V_CEO provides margin against transient overshoot.

Relay Driver Circuit

Signal Buffer for Sensor Interface

Use Scenario: Driving 12 V, 40 mA coil relays from microcontroller GPIO pins in industrial control panels.

IC Role / Device Role / Timing Role: Saturated switch with base current limiting and flyback diode protection.

Use Value: 100 mA I_C rating and 0.25 V V_CE(sat) minimize power dissipation and heat buildup during continuous operation.

Use Scenario: Isolating and buffering analog output from thermistor or potentiometer networks in HVAC control units.

IC Role / Device Role / Timing Role: Unity-gain emitter-follower buffer to prevent loading of high-impedance sensor sources.

Use Value: High h_FE (up to 400) ensures low output impedance (<50 Ω) and minimal signal attenuation across temperature.

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN general-purpose amplifier applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MPSA18	V_CEO = 45 V, h_FE = 100–300, f_T = 100 MHz	Slightly higher breakdown voltage but lower bandwidth; better for higher-voltage switching	Preferred when >40 V rail margin is required and 125 MHz bandwidth is unnecessary
BC547B	V_CEO = 45 V, h_FE = 200–450, f_T = 300 MHz, different pinout (E-C-B vs E-B-C)	Higher gain and bandwidth, but non-interchangeable pinout requires PCB revision	Choose only if redesign allows pinout change and higher f_T is critical

Compared with MPSA18 and BC547B, the MPSA20_D74Z offers the highest f_T among TO-92 NPNs with E-B-C pinout, making it optimal for bandwidth-sensitive amplification where pin compatibility with legacy designs is mandatory.

Availability

MPSA20_D74Z is available at Aetrix Electronics and suitable for audio preamplification, logic level translation, and relay driving applications requiring stable component supply and long-term obsolescence management.

Supply support for MPSA20_D74Z 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

ON Semiconductor is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The MPSA20_D74Z belongs to ON Semiconductor's legacy general-purpose bipolar transistor family, designed for cost-sensitive, high-volume linear and switching functions in consumer and industrial electronics.

FAQ

What is the pin configuration of the MPSA20_D74Z?

The MPSA20_D74Z uses a standard TO-92 package with Emitter-Base-Collector (E-B-C) pinout: Pin 1 = Emitter, Pin 2 = Base, Pin 3 = Collector. This matches JEDEC TO-92 mechanical specification and is identical to the original Fairchild MPSA20. No adapter or footprint modification is needed when replacing legacy stock.

Does the MPSA20_D74Z support operation at elevated temperatures?

Yes, the MPSA20_D74Z is rated for junction temperatures from –55°C to +150°C. However, its power dissipation must be derated above 25°C at 5.0 mW/°C, limiting usable power to ~375 mW at 100°C ambient. Thermal performance depends on PCB copper area-datasheet specifies ≥6 cm² collector pad for full-rated operation.

Is the MPSA20_D74Z suitable for switching applications?

Yes, the MPSA20_D74Z is widely used in low-speed switching due to its 0.25 V V_CE(sat) at I_C = 10 mA/I_B = 1 mA and 100 mA I_C rating. It reliably drives LEDs, small relays, and logic inputs. For high-frequency switching (>1 MHz), its 125 MHz f_T remains sufficient, but layout parasitics become dominant.

How does h_FE variation affect circuit design with the MPSA20_D74Z?

The MPSA20_D74Z exhibits h_FE from 40 to 400 at I_C = 5 mA/V_CE = 10 V. Designers must use emitter degeneration or feedback to stabilize bias points. Circuits relying on fixed h_FE assumptions may fail across production lots unless validated across the full gain range.

Can the MPSA20_D74Z replace the MPSA13 in existing designs?

No-the MPSA20_D74Z is an NPN transistor, while the MPSA13 is a Darlington NPN pair with h_FE > 1000 and higher V_CE(sat). Direct substitution would cause severe gain mismatch and potential saturation failure. The MPSA20_D74Z replaces MPSA18 or 2N3904 in single-transistor amplifier or switch roles-not Darlington equivalents.

MPSA20_D74Z Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-226-3, TO-92-3 (TO-226AA) Formed Leads

Packaging:: Tape & Box (TB)

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 100 mA

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

Vce Saturation (Max) @ Ib, Ic:: 250mV @ 1mA, 10mA

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 40 @ 5mA, 10V

Power - Max:: 625 mW

Frequency - Transition:: 125MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

MPSA20_D74Z FAQ

1.How can I place an order for MPSA20_D74Z through Aetrix?

Please submit a Request for Quotation (RFQ) for MPSA20_D74Z 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 MPSA20_D74Z reliable?

The price and inventory of MPSA20_D74Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MPSA20_D74Z is usually 5 days.

3.What payment methods are accepted for MPSA20_D74Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MPSA20_D74Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MPSA20_D74Z?

MPSA20_D74Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MPSA20_D74Z 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 MPSA20_D74Z?

For technical support, including MPSA20_D74Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MPSA20_D74Z requirements.

6.How does Aetrix verify that MPSA20_D74Z is sourced from the original manufacturer or authorized distributors?

All MPSA20_D74Z 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 MPSA20_D74Z meets industry standards.

7.What is the process for return or replacement of MPSA20_D74Z?

All MPSA20_D74Z units undergo pre-shipment inspection (PSI). If there is an issue with MPSA20_D74Z, 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 MPSA20_D74Z part is unused and in its original packaging.

Return procedure for MPSA20_D74Z:

1.Submit a request within 90 days.

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

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