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

onsemi MPSA18_D27Z

Name: MPSA18_D27Z
Brand: onsemi
SKU: MPSA18_D27Z
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MPSA18_D27Z

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: MPSA18_D27Z.pdf

Description:: TRANS NPN 45V 0.1A TO-92-3

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Product details

Overview

MPSA18_D27Z from Fairchild Semiconductor is an NPN general-purpose amplifier optimized for low-noise, high-gain operation at collector currents from 1 µA to 50 mA. It features a 45 V V_CEO, 100 MHz f_T, 1.5 dB noise figure at 1 kHz, and TO-92 package. Used in preamplifier stages of audio signal chains and sensor interface circuits where gain stability and minimal added noise are critical.

For engineers reviewing the MPSA18_D27Z datasheet, pinout, applications, or equivalent options, key selection criteria include verified h_FE ≥ 400 at 10 µA, V_CE(sat) ≤ 0.3 V at 50 mA, thermal resistance R_θJA = 200 °C/W, and compatibility with standard TO-92 tape-and-reel handling (E-style, D27Z code).

Technical Context

The MPSA18_D27Z implements a silicon planar epitaxial NPN structure designed for linear amplification in low-current analog front-ends. Its process (Fairchild Process 07) delivers tight h_FE distribution and low 1/f noise, with guaranteed V_(BR)CEO ≥ 45 V and NF ≤ 1.5 dB under specified bias conditions.

It operates across –55°C to +150°C junction temperature range and supports continuous I_C up to 100 mA. Small-signal parameters-including C_cb = 3.0 pF and C_eb = 6.5 pF-are characterized at 1 MHz and defined bias points, enabling predictable bandwidth estimation in common-emitter configurations.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - Maximum safe collector-emitter voltage before breakdown; defines headroom for single-supply audio preamp rails.
f_T	100 MHz - Unity-gain bandwidth at I_C = 1 mA, V_CE = 5 V; enables stable gain up to ~10 MHz in practical CE stages.
h_FE	400–1500 - DC current gain range across I_C = 10 µA to 10 mA; supports bias-insensitive gain setting in discrete op-amp inputs.
NF	1.5 dB - Noise figure at V_CE = 5 V, I_C = 100 µA, R_S = 10 kΩ, 1 kHz; ensures minimal degradation of weak signal SNR.
R_θJA	200 °C/W - Junction-to-ambient thermal resistance in still air; determines max power dissipation (≤625 mW) without heatsink.
V_CE(sat)	0.2–0.3 V - Saturation voltage at I_C/I_B = 10–10 and 50–5; confirms suitability for active-load or switching-assist roles.
C_cb	3.0 pF - Collector-base capacitance at V_CB = 5 V, 1 MHz; limits Miller-effect bandwidth reduction in high-gain stages.

Pinout & Package

Package: TO-92, straight lead, no lead clip, E-style tape-and-reel (D27Z packing code). Device outline conforms to JEDEC TO-92 standard with flat side indicating emitter-collector orientation.

Pin/Terminal	Circuit Role	Design Meaning
Emitter (E)	Current sink terminal	First wire off device in D27Z reel orientation; connects to ground or bias network reference point.
Base (B)	Control input	High-impedance node requiring stable DC bias; sensitive to layout-induced noise coupling.
Collector (C)	Current source terminal	Output node for common-emitter gain stage; requires decoupling when driving capacitive loads.

Key Features

Feature	Design Value
Low-noise amplification	1.5 dB NF at 1 kHz enables use in microphone preamps and precision sensor interfaces without external noise filtering.
High DC current gain	h_FE ≥ 400 at 10 µA allows stable biasing with high-value base resistors, reducing power consumption in battery-powered designs.
Wide operating current range	Specified performance from 1 µA to 50 mA supports both ultra-low-power monitoring and medium-gain line-driving applications.
Robust voltage ratings	45 V V_CEO/V_CBO permits use in 24 V industrial signal conditioning without derating concerns.

Applications

Audio Preamplifier Stage	Photodiode Transimpedance Amplifier
Use Scenario: Boosting weak microphone or piezoelectric sensor outputs prior to ADC sampling in portable instrumentation. IC Role / Device Role / Timing Role: Discrete NPN transconductance element configured as common-emitter voltage amplifier with emitter degeneration. Use Value: Delivers >40 dB gain with <1.5 dB added noise floor, preserving dynamic range of sub-10 mV signals.	Use Scenario: Converting nanoamp-level photocurrents from ambient light sensors into measurable voltage outputs. IC Role / Device Role / Timing Role: Low-input-bias-current amplifier in transimpedance configuration with feedback resistor stabilization. Use Value: Enables 100 MΩ+ feedback resistors while maintaining bandwidth >100 kHz due to low C_cb and high f_T.
Low-Power Sensor Interface	Industrial Analog Signal Conditioning
Use Scenario: Amplifying thermistor or RTD bridge outputs in energy-harvesting wireless nodes operating below 100 µA quiescent current. IC Role / Device Role / Timing Role: High-h_FE active load in differential pair front-end, biased at 1–10 µA. Use Value: Maintains usable gain and linearity down to 1 µA I_C, extending battery life without sacrificing measurement resolution.	Use Scenario: Isolating and scaling 4–20 mA loop signals in PLC analog input modules exposed to industrial EMI. IC Role / Device Role / Timing Role: Linear amplifier in isolated current-to-voltage conversion stage with local regulation. Use Value: Withstands 45 V transients and operates reliably from –40°C to +85°C ambient per industrial grade requirements.

Audio Preamplifier Stage

Photodiode Transimpedance Amplifier

Use Scenario: Boosting weak microphone or piezoelectric sensor outputs prior to ADC sampling in portable instrumentation.

IC Role / Device Role / Timing Role: Discrete NPN transconductance element configured as common-emitter voltage amplifier with emitter degeneration.

Use Value: Delivers >40 dB gain with <1.5 dB added noise floor, preserving dynamic range of sub-10 mV signals.

Use Scenario: Converting nanoamp-level photocurrents from ambient light sensors into measurable voltage outputs.

IC Role / Device Role / Timing Role: Low-input-bias-current amplifier in transimpedance configuration with feedback resistor stabilization.

Use Value: Enables 100 MΩ+ feedback resistors while maintaining bandwidth >100 kHz due to low C_cb and high f_T.

Low-Power Sensor Interface

Industrial Analog Signal Conditioning

Use Scenario: Amplifying thermistor or RTD bridge outputs in energy-harvesting wireless nodes operating below 100 µA quiescent current.

IC Role / Device Role / Timing Role: High-h_FE active load in differential pair front-end, biased at 1–10 µA.

Use Value: Maintains usable gain and linearity down to 1 µA I_C, extending battery life without sacrificing measurement resolution.

Use Scenario: Isolating and scaling 4–20 mA loop signals in PLC analog input modules exposed to industrial EMI.

IC Role / Device Role / Timing Role: Linear amplifier in isolated current-to-voltage conversion stage with local regulation.

Use Value: Withstands 45 V transients and operates reliably from –40°C to +85°C ambient per industrial grade requirements.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
2N5088	Identical electrical specs per Fairchild documentation; same Process 07, identical V_CEO, h_FE, and NF.	No functional difference; used interchangeably in legacy designs where 2N5088 is specified.	Select MPSA18_D27Z for new designs requiring TO-92 tape-and-reel (D27Z) packaging and documented Fairchild sourcing traceability.
BC549C	Lower V_CEO (30 V), higher typical h_FE (420–800), slightly higher NF (2.0 dB); different process and gain binning.	Not suitable for 45 V rail applications; acceptable only where supply voltage ≤ 24 V and noise budget allows +0.5 dB penalty.	Choose BC549C only if existing PCB layout uses its pinout and voltage margin is confirmed; not a drop-in replacement.

Compared with 2N5088 and BC549C, the MPSA18_D27Z provides guaranteed 45 V breakdown and 1.5 dB noise figure in a production-qualified TO-92 tape-and-reel format (D27Z), making it optimal for new low-noise analog designs requiring supply headroom and automated assembly compatibility.

Availability

MPSA18_D27Z is available at Aetrix Electronics and suitable for audio preamplifier stages, photodiode transimpedance amplifiers, and low-power sensor interfaces requiring stable component supply, consistent parametric performance, and TO-92 E-style tape-and-reel compatibility.

Supply support for MPSA18_D27Z 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.

The MPSA18_D27Z belongs to Fairchild's legacy NPN general-purpose amplifier product line, engineered specifically for low-noise, high-gain analog signal conditioning in industrial, audio, and sensor applications.

FAQ

What is the maximum collector-emitter voltage rating for MPSA18_D27Z?

The MPSA18_D27Z has a maximum V_CEO rating of 45 V, tested at I_C = 10 mA with base open. This rating is guaranteed per Fairchild's absolute maximum specifications and applies across the full operating temperature range. Exceeding 45 V risks irreversible breakdown. The MPSA18_D27Z must be used within this limit in all circuit configurations, including transient conditions.

Does MPSA18_D27Z support low-current operation down to microamp levels?

Yes, the MPSA18_D27Z is explicitly characterized for operation from 1 µA to 50 mA collector current. Its h_FE is specified at I_C = 10 µA (min 400), and noise figure is measured at I_C = 100 µA. This makes the MPSA18_D27Z suitable for ultra-low-power sensor front-ends where quiescent current must remain below 10 µA without gain collapse.

What does the 'D27Z' suffix indicate in MPSA18_D27Z?

The 'D27Z' suffix identifies the tape-and-reel packaging variant per Fairchild's TO-92 packing specification: E-style orientation (first wire off is emitter), adhesive tape on top side, flat side down, 2000 units per reel. It is not a device revision or performance variant-electrical specs match the base MPSA18. The MPSA18_D27Z ensures compatibility with standard pick-and-place feeders calibrated for E-style TO-92 reels.

Is MPSA18_D27Z pin-compatible with other TO-92 NPN transistors like PN2222A?

No, the MPSA18_D27Z uses standard TO-92 mechanical dimensions but has different internal pin assignment: E-B-C (flat side facing up, leads down, left-to-right). PN2222A follows E-C-B order. Swapping them without board modification causes circuit failure. Always verify pinout using the MPSA18_D27Z datasheet diagram-not generic TO-92 assumptions-before layout or replacement.

What thermal derating applies to MPSA18_D27Z above 25°C ambient?

The MPSA18_D27Z has a total device dissipation limit of 625 mW at 25°C, derated at 5.0 mW/°C above that temperature. At 75°C ambient, maximum allowable power drops to 375 mW. This derating assumes still-air conditions and standard PCB copper area. For sustained operation above 75°C, thermal simulation or empirical testing with the actual MPSA18_D27Z mounting configuration is required.

MPSA18_D27Z Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

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

Voltage - Collector Emitter Breakdown (Max):: 45 V

Vce Saturation (Max) @ Ib, Ic:: 300mV @ 5mA, 50mA

Current - Collector Cutoff (Max):: 50nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 500 @ 10mA, 5V

Power - Max:: 625 mW

Frequency - Transition:: 100MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-92-3

MPSA18_D27Z FAQ

1.How can I place an order for MPSA18_D27Z through Aetrix?

Please submit a Request for Quotation (RFQ) for MPSA18_D27Z 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 MPSA18_D27Z reliable?

The price and inventory of MPSA18_D27Z are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MPSA18_D27Z is usually 5 days.

3.What payment methods are accepted for MPSA18_D27Z?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MPSA18_D27Z transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MPSA18_D27Z?

MPSA18_D27Z orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MPSA18_D27Z 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 MPSA18_D27Z?

For technical support, including MPSA18_D27Z datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MPSA18_D27Z requirements.

6.How does Aetrix verify that MPSA18_D27Z is sourced from the original manufacturer or authorized distributors?

All MPSA18_D27Z 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 MPSA18_D27Z meets industry standards.

7.What is the process for return or replacement of MPSA18_D27Z?

All MPSA18_D27Z units undergo pre-shipment inspection (PSI). If there is an issue with MPSA18_D27Z, 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 MPSA18_D27Z part is unused and in its original packaging.

Return procedure for MPSA18_D27Z:

1.Submit a request within 90 days.

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

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