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

onsemi FJX992TF

Name: FJX992TF
Brand: onsemi
SKU: FJX992TF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: FJX992TF

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: SC-70, SOT-323

Datasheet:: FJX992TF.pdf

Description:: TRANS PNP 120V 0.1A SOT-323

Quantity:: RFQ Add To RFQ list

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Product details

Overview

FJX992TF from onsemi is a PNP bipolar junction transistor (BJT) designed as an audio-frequency low-noise amplifier, featuring V_CEO = −120 V, h_FE = 200–700 at I_C = −2 mA, f_T = 100 MHz, and C_ob = 4 pF; it is used in high-voltage, low-distortion preamplifier stages of professional audio equipment.

For engineers reviewing the FJX992TF datasheet, pinout, applications, or equivalent options, key selection criteria include its high-voltage PNP operation, excellent h_FE linearity, low output capacitance, thermal resistance of 530 °C/W, and SC-70 package compatibility with space-constrained analog signal chains.

Technical Context

This device operates as a linear PNP BJT optimized for low-noise amplification in the audio band, with specified breakdown voltages (V_CEO, V_CBO = −120 V) enabling use in high-headroom biasing schemes. Its h_FE range (200–700) and strong linearity support stable gain control across collector currents from −0.1 mA to −2 mA.

The FJX992TF delivers 100 MHz current-gain bandwidth (f_T) under V_CE = −6 V, I_C = −1 mA conditions, while maintaining low output capacitance (C_ob = 4 pF at V_CB = −10 V), supporting wideband stability in multi-stage amplifier topologies without excessive phase shift.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CEO	−120 V: Enables safe operation in high-voltage audio rails up to ±60 V supply configurations.
h_FE	200–700 at I_C = −2 mA: Supports precise DC biasing and predictable small-signal gain in discrete amplifier designs.
f_T	100 MHz: Ensures adequate bandwidth for full audio spectrum (20 Hz–20 kHz) with margin for harmonic content and slew-rate stability.
C_ob	4 pF at V_CB = −10 V: Minimizes Miller-effect degradation in common-emitter gain stages.
P_D	235 mW at T_A = 25 °C: Defines maximum continuous dissipation before thermal derating begins (1.88 mW/°C above 25 °C).
R_JA	530 °C/W: Indicates thermal performance on standard FR-4 PCB (76 × 114 mm, minimum land pattern); requires careful layout for >100 mW operation.

Pinout & Package

Package: SC-70 (Case 419AB), 3-lead surface-mount plastic package, dimensions 1.25 mm × 2.0 mm × 0.9 mm, rated for reflow soldering per J-STD-020.

Pin/Terminal	Circuit Role	Design Meaning
1	Base	Control terminal for forward-biased PNP operation; requires negative base current relative to emitter to turn on.
2	Emitter	Current source terminal in PNP configuration; typically connected to higher potential (e.g., V_CC or audio rail).
3	Collector	Output current sink terminal; voltage swing referenced to emitter, supports −120 V breakdown rating.

Key Features

Feature	Design Value
High-voltage PNP structure	V_CEO = V_CBO = −120 V enables robust operation in high-supply analog front-ends without derating.
Excellent h_FE linearity	Minimizes harmonic distortion in Class-A amplifier stages where gain consistency across signal amplitude is critical.
Low output capacitance	C_ob = 4 pF reduces frequency-dependent feedback and improves stability in high-gain CE configurations.
Pb-free and halide-free	Complies with RoHS Directive 2011/65/EU and JEDEC JS709B, suitable for environmentally regulated industrial and consumer products.

Applications

Professional Audio Preamplifiers	High-Voltage Analog Signal Conditioning
Use Scenario: Low-noise voltage amplification stage in microphone preamplifiers and channel strips requiring wide dynamic range and minimal added distortion. IC Role / Device Role / Timing Role: Discrete PNP BJT configured in common-emitter topology to provide 30–40 dB gain with controlled input impedance and low thermal drift. Use Value: High h_FE linearity and 100 MHz f_T preserve transient fidelity and harmonic integrity across the full 20 Hz–20 kHz band.	Use Scenario: Input buffer and level-shifting stage in industrial sensor interfaces handling ±40 V sensor outputs before ADC conditioning. IC Role / Device Role / Timing Role: High-breakdown PNP emitter follower providing isolation and rail-to-rail signal translation without saturation risk. Use Value: −120 V V_CEO and −120 V V_CBO allow direct interfacing to high-voltage transducers without external clamping networks.
Discrete Guitar Amplifier Tone Stages	Low-Noise Instrumentation Front-Ends
Use Scenario: Gain cell in overdrive-capable guitar amplifier tone stacks where soft clipping and harmonic richness are design goals. IC Role / Device Role / Timing Role: Class-A biased PNP amplifier operating near I_C = −2 mA to exploit optimal h_FE and linearity region. Use Value: Predictable h_FE spread (200–700) allows matched-pair selection for push-pull symmetry, while low C_ob preserves high-frequency string harmonics.	Use Scenario: First-stage amplifier in medical ECG or precision thermocouple signal chains requiring sub-10 nV/√Hz noise performance. IC Role / Device Role / Timing Role: Low-noise PNP preamp configured with degenerated emitter to optimize noise figure and input impedance matching. Use Value: Verified ICBO ≤ −100 nA and IEBO ≤ −100 nA ensure negligible leakage-induced offset drift at body-temperature operating points.

Professional Audio Preamplifiers

High-Voltage Analog Signal Conditioning

Use Scenario: Low-noise voltage amplification stage in microphone preamplifiers and channel strips requiring wide dynamic range and minimal added distortion.

IC Role / Device Role / Timing Role: Discrete PNP BJT configured in common-emitter topology to provide 30–40 dB gain with controlled input impedance and low thermal drift.

Use Value: High h_FE linearity and 100 MHz f_T preserve transient fidelity and harmonic integrity across the full 20 Hz–20 kHz band.

Use Scenario: Input buffer and level-shifting stage in industrial sensor interfaces handling ±40 V sensor outputs before ADC conditioning.

IC Role / Device Role / Timing Role: High-breakdown PNP emitter follower providing isolation and rail-to-rail signal translation without saturation risk.

Use Value: −120 V V_CEO and −120 V V_CBO allow direct interfacing to high-voltage transducers without external clamping networks.

Discrete Guitar Amplifier Tone Stages

Low-Noise Instrumentation Front-Ends

Use Scenario: Gain cell in overdrive-capable guitar amplifier tone stacks where soft clipping and harmonic richness are design goals.

IC Role / Device Role / Timing Role: Class-A biased PNP amplifier operating near I_C = −2 mA to exploit optimal h_FE and linearity region.

Use Value: Predictable h_FE spread (200–700) allows matched-pair selection for push-pull symmetry, while low C_ob preserves high-frequency string harmonics.

Use Scenario: First-stage amplifier in medical ECG or precision thermocouple signal chains requiring sub-10 nV/√Hz noise performance.

IC Role / Device Role / Timing Role: Low-noise PNP preamp configured with degenerated emitter to optimize noise figure and input impedance matching.

Use Value: Verified ICBO ≤ −100 nA and IEBO ≤ −100 nA ensure negligible leakage-induced offset drift at body-temperature operating points.

Equivalent & Alternatives

The following parts are listed as comparable options for similar PNP audio-frequency amplifier applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBT4403	V_CEO = −40 V, h_FE = 100–300, f_T = 200 MHz, C_ob = 6 pF	Lower breakdown limits restrict use to ≤±20 V supplies; higher f_T offers wider bandwidth but reduced voltage headroom.	Select when supply rails are ≤±15 V and bandwidth >100 MHz is prioritized over voltage margin.
FMMT718	V_CEO = −100 V, h_FE = 250–600, f_T = 125 MHz, C_ob = 3.5 pF, SC-70 package	10 V lower V_CEO, slightly higher f_T, marginally lower C_ob; otherwise functionally aligned for same PCB footprint.	Preferred for new designs needing tighter h_FE tolerance and improved high-frequency response within same physical constraints.

Compared with MMBT4403 and FMMT718, the FJX992TF provides the highest voltage rating (−120 V) among SC-70 PNP BJTs, making it uniquely suitable for high-rail audio and industrial analog systems where breakdown margin directly impacts reliability and signal integrity.

Availability

FJX992TF is available at Aetrix Electronics and suitable for professional audio preamplifiers, high-voltage sensor interfaces, discrete guitar amplifier tone stages, and low-noise instrumentation front-ends requiring stable component supply and consistent parametric performance across production lots.

Supply support for FJX992TF 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 (Semiconductor Components Industries, LLC) is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The FJX992TF belongs to onsemi's discrete bipolar transistor product line, engineered specifically for high-fidelity, high-voltage analog signal amplification where low noise, gain linearity, and rugged breakdown performance are essential.

FAQ

What is the maximum collector-emitter voltage rating for the FJX992TF?

The FJX992TF has a guaranteed V_CEO rating of −120 V at T_A = 25 °C, verified under pulsed test conditions (pulse width < 300 µs, duty cycle ≤ 2.0%). This rating applies to DC and low-duty-cycle switching applications; sustained operation near this limit requires thermal derating per the R_JA = 530 °C/W specification. The FJX992TF must not be operated beyond this absolute maximum to prevent junction damage.

Does the FJX992TF support Pb-free assembly processes?

Yes, the FJX992TF is explicitly marked as Pb-free and halide-free per the onsemi datasheet, compliant with RoHS Directive 2011/65/EU and JEDEC JS709B. It is qualified for standard lead-free reflow profiles (per J-STD-020), including peak temperatures up to 260 °C, and uses matte tin plating on its SC-70 terminations. The FJX992TF is suitable for high-reliability consumer and industrial manufacturing without lead-based solder concerns.

What is the typical current gain bandwidth product (f_T) of the FJX992TF?

The FJX992TF has a typical f_T of 100 MHz when tested at V_CE = −6 V and I_C = −1 mA. This value is measured under small-signal conditions and reflects the frequency at which the short-circuit current gain drops to unity. Designers should validate f_T in their actual circuit context, as bias point, temperature, and parasitic layout effects influence real-world bandwidth. The FJX992TF maintains usable gain well into the ultrasonic range, supporting clean audio reproduction.

How does the FJX992TF's h_FE vary with collector current?

The FJX992TF exhibits a specified h_FE range of 150 (min) at I_C = −0.1 mA and 200–700 at I_C = −2 mA, confirming strong gain linearity across its intended operating window. Per Figure 1 in the datasheet, h_FE peaks near I_C = −1 mA and remains stable between −0.5 mA and −5 mA. This behavior makes the FJX992TF especially suitable for Class-A amplifier designs where consistent gain across signal amplitude is critical to minimizing harmonic distortion.

What is the thermal resistance (R_JA) of the FJX992TF in its SC-70 package?

The FJX992TF has a specified R_JA of 530 °C/W when mounted on a standard FR-4 PCB measuring 76 × 114 × 1.57 mm with minimum land pattern size. This value assumes natural convection only and no additional copper pour or thermal vias. At ambient temperatures above 25 °C, power dissipation must be reduced by 1.88 mW per degree Celsius. For reliable operation above 100 mW, thermal design using the FJX992TF must account for this relatively high R_JA through layout optimization or derating.

FJX992TF Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: SC-70, SOT-323

Packaging:: Tape & Reel (TR)

Product Status:: Active

Transistor Type:: PNP

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

Voltage - Collector Emitter Breakdown (Max):: 120 V

Vce Saturation (Max) @ Ib, Ic:: 300mV @ 1mA, 10mA

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

DC Current Gain (hFE) (Min) @ Ic, Vce:: 200 @ 2mA, 6V

Power - Max:: 235 mW

Frequency - Transition:: 100MHz

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-323

FJX992TF FAQ

1.How can I place an order for FJX992TF through Aetrix?

Please submit a Request for Quotation (RFQ) for FJX992TF 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 FJX992TF reliable?

The price and inventory of FJX992TF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FJX992TF is usually 5 days.

3.What payment methods are accepted for FJX992TF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FJX992TF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for FJX992TF?

FJX992TF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your FJX992TF 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 FJX992TF?

For technical support, including FJX992TF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FJX992TF requirements.

6.How does Aetrix verify that FJX992TF is sourced from the original manufacturer or authorized distributors?

All FJX992TF 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 FJX992TF meets industry standards.

7.What is the process for return or replacement of FJX992TF?

All FJX992TF units undergo pre-shipment inspection (PSI). If there is an issue with FJX992TF, 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 FJX992TF part is unused and in its original packaging.

Return procedure for FJX992TF:

1.Submit a request within 90 days.

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

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