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

onsemi MPSA18RLRA

Name: MPSA18RLRA
Brand: onsemi
SKU: MPSA18RLRA
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MPSA18RLRA

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: MPSA18RLRA.pdf

Description:: TRANS NPN 45V 0.2A TO92

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MPSA18RLRA from onsemi is an NPN silicon low-noise general-purpose transistor in TO-92 package, rated for V_CEO = 45 V, I_C = 200 mA, and P_D = 625 mW at T_A = 25°C, with h_FE up to 1500 and f_T = 100–160 MHz - used in audio preamplifier stages, RF amplifiers, and low-noise signal conditioning circuits.

For engineers reviewing the MPSA18RLRA datasheet, pinout, applications, or equivalent options, key selection criteria include noise figure (NF = 0.5 dB @ 1 kHz, R_S = 10 kΩ), V_CE(sat) ≤ 0.3 V, C_cb = 1.7–3.0 pF, and guaranteed h_FE ≥ 400 at I_C = 10 mA - critical for high-gain, low-distortion analog front-ends.

Technical Context

The MPSA18RLRA operates as a discrete NPN bipolar junction transistor optimized for low-noise amplification, with base-emitter and collector-base junctions engineered for stable h_FE across −55°C to +150°C junction temperature range and low capacitance (C_eb = 5.6–6.5 pF, C_cb = 1.7–3.0 pF) to support wideband small-signal performance.

Its noise model features equivalent input noise voltage (e_n) of 6.5 nV/√Hz @ 100 Hz and R_S = 1 kΩ, and noise figure as low as 0.5 dB under specified conditions - enabling use in sensitive microphone preamps and instrumentation amplifier input stages where signal integrity dominates design priority.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - supports rail-to-rail operation in ±15 V analog systems without breakdown risk
I_C (max)	200 mA - sufficient drive capability for line-level output buffers and medium-current gain stages
h_FE	400–1500 - enables high DC gain in single-stage amplifiers with predictable bias stability
f_T	100–160 MHz - ensures usable bandwidth beyond audio spectrum into low-VHF RF applications
NF	0.5 dB @ 1 kHz, R_S = 10 kΩ - meets stringent noise requirements in electret microphone and sensor interface designs
V_CE(sat)	≤ 0.3 V @ I_C = 50 mA, I_B = 5 mA - minimizes voltage drop and power loss in saturated-switching configurations
C_cb	1.7–3.0 pF - limits Miller effect, preserving high-frequency gain and phase margin in CE amplifiers

Pinout & Package

Package: TO-92 (Case 29-11, Style 1), through-hole, Pb-free compatible, 2000-unit tape-and-reel shipping format.

Pin/Terminal	Circuit Role	Design Meaning
1	Emitter	Current sink node; connects to ground or emitter degeneration resistor in common-emitter configuration
2	Base	Control terminal; requires current-limited bias network to set operating point and ensure h_FE-stable Q-point
3	Collector	Current source node; interfaces with load resistor or active load in amplification or switching topologies

Key Features

Feature	Design Value
Low noise figure	NF = 0.5 dB @ 1 kHz enables clean signal amplification in mic preamp and sensor front-ends
High DC current gain	h_FE ≥ 400 at I_C = 10 mA allows robust biasing with minimal base drive current
Wide f_T bandwidth	f_T ≥ 100 MHz supports stable gain up to ~10 MHz in practical CE amplifier layouts
Low capacitance terminals	C_cb ≤ 3.0 pF and C_eb ≤ 6.5 pF reduce frequency-dependent feedback and improve HF stability
Extended temperature range	−55°C to +150°C operation supports industrial and automotive under-hood environments

Applications

Audio Preamp Stage	RF Signal Amplifier
Use Scenario: Electret condenser microphone signal amplification in voice-controlled IoT devices. IC Role / Device Role / Timing Role: Low-noise NPN transistor configured in common-emitter topology as first gain stage. Use Value: NF = 0.5 dB and e_n = 6.5 nV/√Hz preserve SNR in sub-10 mV microphone outputs.	Use Scenario: 10–30 MHz IF amplifier in AM/FM receiver front-end modules. IC Role / Device Role / Timing Role: Small-signal NPN amplifier with f_T ≥ 100 MHz and C_cb ≤ 3.0 pF. Use Value: High f_T and low Miller capacitance maintain gain flatness and phase margin across band.
Instrumentation Input Buffer	Low-Power Sensor Interface
Use Scenario: High-impedance transducer signal conditioning in portable medical sensors. IC Role / Device Role / Timing Role: Emitter-follower buffer with h_FE ≥ 1100 to minimize loading of piezoresistive elements. Use Value: High h_FE and low V_BE(on) = 0.6–0.7 V enable accurate DC-coupled buffering with <1% error.	Use Scenario: Thermistor or RTD signal amplification in battery-powered environmental monitors. IC Role / Device Role / Timing Role: Low-power, low-noise NPN gain stage operating at I_C = 100 µA–1 mA. Use Value: Stable h_FE down to 100 µA and NF < 4.0 dB @ 100 Hz allow precision DC-coupled measurement.

Audio Preamp Stage

RF Signal Amplifier

Use Scenario: Electret condenser microphone signal amplification in voice-controlled IoT devices.

IC Role / Device Role / Timing Role: Low-noise NPN transistor configured in common-emitter topology as first gain stage.

Use Value: NF = 0.5 dB and e_n = 6.5 nV/√Hz preserve SNR in sub-10 mV microphone outputs.

Use Scenario: 10–30 MHz IF amplifier in AM/FM receiver front-end modules.

IC Role / Device Role / Timing Role: Small-signal NPN amplifier with f_T ≥ 100 MHz and C_cb ≤ 3.0 pF.

Use Value: High f_T and low Miller capacitance maintain gain flatness and phase margin across band.

Instrumentation Input Buffer

Low-Power Sensor Interface

Use Scenario: High-impedance transducer signal conditioning in portable medical sensors.

IC Role / Device Role / Timing Role: Emitter-follower buffer with h_FE ≥ 1100 to minimize loading of piezoresistive elements.

Use Value: High h_FE and low V_BE(on) = 0.6–0.7 V enable accurate DC-coupled buffering with <1% error.

Use Scenario: Thermistor or RTD signal amplification in battery-powered environmental monitors.

IC Role / Device Role / Timing Role: Low-power, low-noise NPN gain stage operating at I_C = 100 µA–1 mA.

Use Value: Stable h_FE down to 100 µA and NF < 4.0 dB @ 100 Hz allow precision DC-coupled measurement.

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-noise NPN transistor applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
BC548C	Lower h_FE (420–800), higher V_CE(sat) (0.5 V), no guaranteed NF spec	Acceptable in non-critical audio stages but not recommended for <1 dB NF designs	Select BC548C only when cost sensitivity outweighs noise and gain requirements
2N5088	Higher h_FE (400–1200), lower NF (0.4 dB), same TO-92 package and pinout	Direct substitute in ultra-low-noise preamps; slightly lower f_T (50 MHz) limits HF use	Prefer 2N5088 where lowest possible NF is mandatory and bandwidth ≤ 5 MHz suffices

Compared with BC548C and 2N5088, the MPSA18RLRA delivers superior balance of noise performance (0.5 dB), gain (up to 1500), and bandwidth (160 MHz), making it optimal for broadband, high-fidelity analog signal chains where both fidelity and headroom matter.

Availability

MPSA18RLRA is available at Aetrix Electronics and suitable for audio preamplifiers, RF intermediate-frequency amplifiers, and low-noise sensor interface circuits requiring stable component supply, consistent parametric performance, and long-term manufacturability.

Supply support for MPSA18RLRA 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 delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The MPSA18RLRA belongs to onsemi's legacy low-noise bipolar transistor product line, designed specifically for high-fidelity analog signal amplification in consumer, professional audio, and precision instrumentation systems.

FAQ

What is the maximum collector-emitter voltage rating for MPSA18RLRA?

The MPSA18RLRA has a maximum collector-emitter voltage (V_CEO) rating of 45 Vdc, verified per onsemi's official datasheet (Rev. 3, January 2006). This rating applies under continuous DC conditions with I_B = 0 and defines the absolute upper limit before avalanche breakdown occurs. Exceeding this voltage risks permanent device failure, and derating is recommended for reliability in high-temperature or transient-prone environments. The MPSA18RLRA must not be operated above 45 V in any circuit configuration.

Does MPSA18RLRA have a guaranteed minimum DC current gain (h_FE) at 10 mA collector current?

Yes, the MPSA18RLRA guarantees a minimum h_FE of 400 at I_C = 10 mA, V_CE = 5.0 Vdc, and T_A = 25°C, as specified in the "ON CHARACTERISTICS" table of its official datasheet. This value is tested and binned during production. The typical h_FE is 580, and maximum is 1500 - enabling predictable bias design in linear amplifier stages. The MPSA18RLRA's h_FE remains stable across temperature, supporting robust operation from −55°C to +150°C.

Is MPSA18RLRA suitable for low-noise audio preamplifier applications?

Yes, the MPSA18RLRA is explicitly characterized as a "Low Noise Transistor" and provides a noise figure (NF) of 0.5 dB at 1 kHz with R_S = 10 kΩ and an equivalent input noise voltage (e_n) of 6.5 nV/√Hz at 100 Hz. These values are measured and guaranteed per onsemi's test conditions. Its low C_cb (1.7–3.0 pF) and high h_FE make the MPSA18RLRA well-suited for electret microphone preamps, phono stages, and other high-SNR analog front-ends where noise floor directly impacts system performance.

What is the thermal resistance from junction to ambient (R_θJA) for MPSA18RLRA in standard PCB mounting?

The MPSA18RLRA has a thermal resistance from junction to ambient (R_θJA) of 200°C/W when soldered onto a typical printed circuit board, as stated in the "THERMAL CHARACTERISTICS" section of its datasheet. This value assumes standard JEDEC test conditions (single device, FR-4 board, 1 in² copper pad). For reliable operation at full 625 mW dissipation, ambient temperature must remain below 115°C - underscoring the need for proper layout, copper pour, and airflow. The MPSA18RLRA's R_θJA is consistent across all TO-92 variants including MPSA18RLRA.

What packaging format does MPSA18RLRA ship in, and is it RoHS-compliant?

The MPSA18RLRA ships in tape-and-reel format with 2000 units per reel, as confirmed in the "ORDERING INFORMATION" section of the onsemi datasheet. It is offered in a Pb-free (RoHS-compliant) version - denoted by the "G" suffix in alternate part numbers like MPSA18RLRAG - and the MPSA18RLRA itself meets J-STD-609 Category 1 marking requirements. Lead finish is matte tin, and the device complies with EU RoHS Directive 2011/65/EU and China RoHS II. Traceability documentation is available upon request for MPSA18RLRA.

MPSA18RLRA 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):: 200 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:: 160MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

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

MPSA18RLRA FAQ

1.How can I place an order for MPSA18RLRA through Aetrix?

Please submit a Request for Quotation (RFQ) for MPSA18RLRA 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 MPSA18RLRA reliable?

The price and inventory of MPSA18RLRA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MPSA18RLRA is usually 5 days.

3.What payment methods are accepted for MPSA18RLRA?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MPSA18RLRA transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MPSA18RLRA?

MPSA18RLRA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MPSA18RLRA 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 MPSA18RLRA?

For technical support, including MPSA18RLRA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MPSA18RLRA requirements.

6.How does Aetrix verify that MPSA18RLRA is sourced from the original manufacturer or authorized distributors?

All MPSA18RLRA 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 MPSA18RLRA meets industry standards.

7.What is the process for return or replacement of MPSA18RLRA?

All MPSA18RLRA units undergo pre-shipment inspection (PSI). If there is an issue with MPSA18RLRA, 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 MPSA18RLRA part is unused and in its original packaging.

Return procedure for MPSA18RLRA:

1.Submit a request within 90 days.

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

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