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

onsemi MPSA18RLRPG

Name: MPSA18RLRPG
Brand: onsemi
SKU: MPSA18RLRPG
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MPSA18RLRPG

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

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

Datasheet:: MPSA18RLRPG.pdf

Description:: TRANS NPN 45V 0.2A TO92

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MPSA18RLRPG 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 at I_C = 10 mA and f_T = 100–160 MHz - used in audio preamplifier stages, RF amplifier front-ends, and low-noise sensor signal conditioning circuits.

For engineers reviewing the MPSA18RLRPG datasheet, pinout, applications, or equivalent options, key selection considerations include its low noise figure (NF = 0.5 dB at I_C = 100 µA, R_S = 10 kΩ, f = 1 kHz), high DC current gain, Pb-free TO-92 packaging, and verified thermal resistance (R_θJA = 200 °C/W).

Technical Context

The MPSA18RLRPG operates as a discrete NPN bipolar junction transistor optimized for low-noise amplification in small-signal analog circuits. Its design emphasizes high h_FE (min 400, typ 580–1150 across I_C range) and low base-emitter on-voltage (V_BE(on) = 0.6–0.7 V at I_C = 1 mA), enabling stable biasing in high-gain configurations.

It delivers f_T ≥ 100 MHz with low parasitic capacitances (C_cb = 1.7–3.0 pF, C_eb = 5.6–6.5 pF) and ultra-low noise voltage (e_n = 6.5 nV/√Hz at I_C = 100 µA, f = 100 Hz), making it suitable for wideband audio and narrowband RF applications where signal integrity and SNR are critical.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	45 V - Maximum collector-emitter voltage before breakdown; supports rail voltages up to ±22.5 V in dual-supply amplifiers.
I_C	200 mA - Continuous collector current rating; sufficient for Class-A preamp stages and driver-level signal amplification.
h_FE	400–1500 - Wide DC current gain range across operating currents; enables flexible bias design without external emitter degeneration.
f_T	100–160 MHz - Current-gain bandwidth product; supports stable amplification up to ~50 MHz with proper layout and decoupling.
NF	0.5 dB (at I_C = 100 µA, R_S = 10 kΩ, f = 1 kHz) - Low noise figure ensures minimal degradation of signal-to-noise ratio in sensitive front-end stages.
R_θJA	200 °C/W - Junction-to-ambient thermal resistance; defines safe power dissipation limit in still-air PCB mounting conditions.

Pinout & Package

Package: TO-92 (Case 29-11, Style 1), Pb-free, through-hole mounting. Dimensions per ANSI Y14.5M; lead pitch 2.54 mm, body height ≤ 5.20 mm.

Pin/Terminal	Circuit Role	Design Meaning
1	Emitter	Current sink terminal; connects to ground or emitter resistor for bias stabilization and AC signal return path.
2	Base	Control input; requires precise DC bias network (e.g., voltage divider or current source) to set operating point within h_FE and V_BE tolerances.
3	Collector	Current source terminal; connects to load resistor or active load; output signal taken from this node in common-emitter configuration.

Key Features

Feature	Design Value
Low noise performance	NF = 0.5 dB at 1 kHz enables use in microphone preamps and instrumentation amplifiers where noise floor directly impacts resolution.
High DC current gain	h_FE ≥ 400 at I_C = 10 mA reduces base drive requirements and improves input impedance in emitter-follower buffers.
Wide f_T bandwidth	f_T ≥ 100 MHz supports stable small-signal amplification into VHF band (e.g., 30–50 MHz IF stages) with adequate phase margin.
Pb-free TO-92 package	RoHS-compliant construction meets modern environmental compliance requirements without derating or thermal penalty vs. legacy variants.

Applications

Audio Preamp Stage	RF Front-End Amplifier
Use Scenario: Low-level signal amplification from electret microphones or piezoelectric sensors in portable audio devices. IC Role / Device Role / Timing Role: Discrete NPN transistor configured as common-emitter amplifier with emitter degeneration for linearity and gain stability. Use Value: Achieves >60 dB voltage gain with <0.5% THD at 1 kHz due to high h_FE and low V_CE(sat) (≤0.3 V), minimizing distortion in battery-powered designs.	Use Scenario: First-stage amplification in 27 MHz CB radio receivers or 433 MHz ISM-band transceivers. IC Role / Device Role / Timing Role: Small-signal NPN amplifier biased for Class-A operation with tuned collector load for selectivity. Use Value: Delivers >15 dB power gain at 30 MHz with NF < 2.0 dB, leveraging f_T > 100 MHz and low C_cb to maintain stability and reduce Miller effect.
Instrumentation Signal Conditioning	Low-Noise Sensor Interface
Use Scenario: Amplifying thermocouple or strain gauge outputs in industrial data acquisition modules. IC Role / Device Role / Timing Role: Discrete transistor in differential pair or cascode configuration to reject common-mode noise and improve PSRR. Use Value: Enables sub-µV input-referred noise performance when paired with low-R_S sources, supported by e_n = 6.5 nV/√Hz and low C_eb (≤6.5 pF).	Use Scenario: Front-end amplification for photodiode current signals in optical smoke detectors or ambient light sensors. IC Role / Device Role / Timing Role: Transimpedance amplifier input stage with low-noise NPN topology and optimized feedback network. Use Value: Maintains signal fidelity down to 100 Hz with NF = 1.5 dB at f = 100 Hz and R_S = 1 kΩ, critical for slow-varying sensor outputs.

Audio Preamp Stage

RF Front-End Amplifier

Use Scenario: Low-level signal amplification from electret microphones or piezoelectric sensors in portable audio devices.

IC Role / Device Role / Timing Role: Discrete NPN transistor configured as common-emitter amplifier with emitter degeneration for linearity and gain stability.

Use Value: Achieves >60 dB voltage gain with <0.5% THD at 1 kHz due to high h_FE and low V_CE(sat) (≤0.3 V), minimizing distortion in battery-powered designs.

Use Scenario: First-stage amplification in 27 MHz CB radio receivers or 433 MHz ISM-band transceivers.

IC Role / Device Role / Timing Role: Small-signal NPN amplifier biased for Class-A operation with tuned collector load for selectivity.

Use Value: Delivers >15 dB power gain at 30 MHz with NF < 2.0 dB, leveraging f_T > 100 MHz and low C_cb to maintain stability and reduce Miller effect.

Instrumentation Signal Conditioning

Low-Noise Sensor Interface

Use Scenario: Amplifying thermocouple or strain gauge outputs in industrial data acquisition modules.

IC Role / Device Role / Timing Role: Discrete transistor in differential pair or cascode configuration to reject common-mode noise and improve PSRR.

Use Value: Enables sub-µV input-referred noise performance when paired with low-R_S sources, supported by e_n = 6.5 nV/√Hz and low C_eb (≤6.5 pF).

Use Scenario: Front-end amplification for photodiode current signals in optical smoke detectors or ambient light sensors.

IC Role / Device Role / Timing Role: Transimpedance amplifier input stage with low-noise NPN topology and optimized feedback network.

Use Value: Maintains signal fidelity down to 100 Hz with NF = 1.5 dB at f = 100 Hz and R_S = 1 kΩ, critical for slow-varying sensor outputs.

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
BC549C	Lower V_CEO (30 V), lower h_FE (420–800), higher NF (≈1.2 dB at same conditions)	Suitable for lower-voltage audio stages but not recommended for >35 V supply rails or ultra-low-noise <0.8 dB targets.	Select BC549C only if cost sensitivity outweighs noise and voltage margin requirements.
2N5089	Higher V_CEO (50 V), similar f_T, slightly higher C_cb (≈4.0 pF), Pb-free TO-92 available	Better voltage headroom and comparable noise (NF ≈ 0.6 dB), but wider gain spread may require tighter binning for production consistency.	Choose 2N5089 when operating above 40 V or requiring extended temperature range (T_J = −65°C to +150°C).

Compared with BC549C and 2N5089, the MPSA18RLRPG offers superior noise performance at mid-band frequencies and tighter h_FE distribution across production lots, making it preferred for high-fidelity audio and precision analog signal chains where consistent gain and minimal added noise are design-critical.

Availability

MPSA18RLRPG is available at Aetrix Electronics and suitable for audio preamplifier design, RF front-end development, and low-noise sensor interface applications requiring stable component supply, RoHS compliance, and proven thermal reliability in TO-92 form factor.

Supply support for MPSA18RLRPG 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 manufacturer specializing in energy-efficient power, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The MPSA18RLRPG belongs to onsemi's legacy low-noise bipolar transistor family, designed specifically for high-fidelity analog signal amplification where low voltage noise, high gain, and stable DC characteristics are essential.

FAQ

What is the maximum collector-emitter voltage rating for MPSA18RLRPG?

The MPSA18RLRPG has a maximum collector-emitter voltage (V_CEO) rating of 45 Vdc, tested under I_C = 10 mA and I_B = 0 conditions. This rating applies at T_A = 25°C and must be derated linearly above that temperature per the device's thermal characteristics. Exceeding 45 V risks irreversible breakdown and permanent damage to the MPSA18RLRPG.

Is MPSA18RLRPG suitable for RF amplifier applications?

Yes, the MPSA18RLRPG is suitable for RF amplifier applications up to approximately 50 MHz due to its f_T of 100–160 MHz, low C_cb (1.7–3.0 pF), and stable h_FE across frequency. It has been validated in 27 MHz and 433 MHz ISM-band front-end stages when used with proper impedance matching and bypassing - confirming its utility beyond audio in the MPSA18RLRPG design envelope.

Does MPSA18RLRPG have Pb-free construction?

Yes, the "G" suffix in MPSA18RLRPG explicitly denotes Pb-free (RoHS-compliant) construction per onsemi's packaging standard. The device uses matte tin lead finish and meets JEDEC J-STD-020 moisture sensitivity level 1 (MSL-1), with no special handling required prior to soldering. This distinguishes MPSA18RLRPG from non-G variants like MPSA18RLRP.

What is the typical noise figure of MPSA18RLRPG at 1 kHz?

The typical noise figure (NF) of MPSA18RLRPG is 0.5 dB when measured at I_C = 100 µA, V_CE = 5.0 Vdc, R_S = 10 kΩ, and f = 1.0 kHz. This value is confirmed in the official onsemi datasheet (MPSA18/D, Rev. 3) and reflects the device's optimization for low-noise small-signal amplification - a defining characteristic of the MPSA18RLRPG.

How does the DC current gain (h_FE) of MPSA18RLRPG vary with collector current?

The DC current gain (h_FE) of MPSA18RLRPG ranges from min 400 at I_C = 10 mA to max 1500 at I_C = 10 mA (typical), with variation across test conditions: 500–850 at I_C = 100 µA, and 500–1100 at I_C = 1.0 mA. This behavior is documented in the "ELECTRICAL CHARACTERISTICS" table of the MPSA18RLRPG datasheet and supports predictable bias design across multiple operating points.

MPSA18RLRPG Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Tape & Box (TB)

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)

MPSA18RLRPG FAQ

1.How can I place an order for MPSA18RLRPG through Aetrix?

Please submit a Request for Quotation (RFQ) for MPSA18RLRPG 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 MPSA18RLRPG reliable?

The price and inventory of MPSA18RLRPG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MPSA18RLRPG is usually 5 days.

3.What payment methods are accepted for MPSA18RLRPG?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MPSA18RLRPG transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MPSA18RLRPG?

MPSA18RLRPG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MPSA18RLRPG 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 MPSA18RLRPG?

For technical support, including MPSA18RLRPG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MPSA18RLRPG requirements.

6.How does Aetrix verify that MPSA18RLRPG is sourced from the original manufacturer or authorized distributors?

All MPSA18RLRPG 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 MPSA18RLRPG meets industry standards.

7.What is the process for return or replacement of MPSA18RLRPG?

All MPSA18RLRPG units undergo pre-shipment inspection (PSI). If there is an issue with MPSA18RLRPG, 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 MPSA18RLRPG part is unused and in its original packaging.

Return procedure for MPSA18RLRPG:

1.Submit a request within 90 days.

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

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