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onsemi FJX3906TF
- Part No.:
- FJX3906TF
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- SC-70, SOT-323
- Datasheet:
-
FJX3906TF.pdf
- Description:
- TRANS PNP 40V 0.2A SOT-323
- Quantity:
- Payment:
- Shipping:
Inventory:7,376
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Product details
Overview
FJX3906TF from ON Semiconductor is a PNP epitaxial silicon transistor in SC-70 (SOT-323) package, rated for -40 V collector-base voltage, -40 V collector-emitter breakdown voltage, and -200 mA continuous collector current. It delivers DC current gain (hFE) of 60–300 across 0.1–50 mA IC range and supports 250 MHz current gain bandwidth product, suitable for general-purpose switching and amplification in portable power management circuits.
For engineers reviewing the FJX3906TF datasheet, pinout, applications, or equivalent options, key selection criteria include its PNP polarity, SC-70 thermal resistance (357 °C/W), saturation voltages (VCE(sat) = -0.25 V at IC = -10 mA/IB = -1 mA), noise figure (4 dB), and turn-off time (300 ns) in low-power analog and digital interface stages.
Technical Context
This device operates as a discrete PNP bipolar junction transistor with epitaxial base construction, enabling stable hFE over temperature and frequency. Its breakdown ratings (BVCBO = -40 V, BVCEO = -40 V) and low Cob (4.5 pF at VCB = -5 V) support reliable operation in low-voltage signal switching and biasing networks.
The FJX3906TF features defined saturation behavior (VBE(sat) = -0.65 to -0.95 V) and fast switching dynamics (tON = 70 ns, tOFF = 300 ns), optimized for use in compact DC-DC converter feedback paths, LED driver current sinks, and logic-level translation where low quiescent current and predictable gain are required.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Device Type | PNP epitaxial silicon bipolar transistor - enables sink-current control and complementary pairing with NPN devices |
| VCBO / VCES | -40 V / -40 V - defines maximum reverse-biased voltage tolerance between collector-base and collector-emitter terminals |
| IC(max) | -200 mA - maximum continuous collector current without thermal derating, usable in medium-current switching loads |
| hFE @ IC = -10 mA | 100–300 - provides predictable current amplification for base-driven load control with minimal drive current |
| fT | 250 MHz - supports RF-capable amplification and high-speed switching up to ~100 MHz practical bandwidth |
| VCE(sat) @ IC/IB = -10 mA/-1 mA | -0.25 V - ensures low conduction loss in saturated switch mode, reducing power dissipation in battery-powered systems |
| RθJA | 357 °C/W - thermal resistance on standard FR-4 PCB (76 × 114 mm), defining safe power handling under ambient conditions |
Pinout & Package
Package: SC-70 (SOT-323), 3-lead plastic surface-mount package with 1.25 mm body width and standardized land pattern per EIAJ SC-70 specification.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Base) | Control input terminal | Receives forward-biased current to enable conduction; requires negative voltage relative to emitter for PNP turn-on |
| 2 (Emitter) | Current source terminal | Connected to higher potential rail; supplies current to collector when device is active |
| 3 (Collector) | Output/current sink terminal | Delivers controlled current to load; polarity reversal vs. NPN enables high-side sourcing or low-side sinking configurations |
Key Features
| Feature | Design Value |
|---|---|
| Low VCE(sat) | -0.25 V at -10 mA collector current enables <1 mW conduction loss in portable load switches |
| High fT | 250 MHz bandwidth supports audio-frequency amplification and fast digital signal conditioning |
| Low Cob | 4.5 pF output capacitance minimizes high-frequency loading in RF amplifier stages |
| Wide hFE range | 60–300 gain spread accommodates production variation while maintaining functional margin in bias networks |
| SC-70 footprint | Compact 2.1 × 1.25 mm outline allows dense placement in space-constrained IoT sensor nodes and wearables |
Applications
| Portable DC-DC Feedback | LED Current Sink |
|---|---|
Use Scenario: Regulating output voltage in step-down converters using optocoupler-isolated feedback loops. IC Role / Device Role / Timing Role: PNP transistor acting as current-controlled switch to pull optocoupler LED anode to ground, modulating feedback signal based on output error. Use Value: Low VCE(sat) (-0.25 V) reduces power loss in feedback path; tight hFE consistency ensures stable loop gain across temperature. | Use Scenario: Driving indicator LEDs in handheld medical devices with precise current limiting. IC Role / Device Role / Timing Role: Fixed-gain current sink configured with emitter resistor to set LED current independent of supply variation. Use Value: Predictable hFE (100–300 at -10 mA) enables ±5% current accuracy; SC-70 size fits ultra-thin front-panel layouts. |
| Logic Level Translation | Low-Power Sensor Biasing |
Use Scenario: Converting 3.3 V microcontroller GPIO outputs to interface with 5 V analog subsystems. IC Role / Device Role / Timing Role: PNP-based level shifter with base driven by MCU, collector connected to 5 V rail, emitter driving target input. Use Value: Fast tON (70 ns) and tOFF (300 ns) support >1 MHz translation rates; low Cob avoids signal integrity degradation. | Use Scenario: Providing stable bias current to MEMS microphone preamplifiers in always-on voice detection modules. IC Role / Device Role / Timing Role: Constant-current source configured in emitter-follower configuration to set sensor operating point. Use Value: Low ICEX (-50 nA) prevents leakage-induced offset drift; 4 dB noise figure preserves SNR in audio front-end chains. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PNP transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MMBT3906LT1G | Same SC-70 package, identical absolute max ratings, but hFE min = 100 @ -10 mA (vs. 60 for FJX3906TF); slightly lower RθJA (333 °C/W) | Better suited for gain-critical bias networks requiring guaranteed minimum hFE; otherwise functionally interchangeable in switching roles | Select MMBT3906LT1G when hFE consistency at mid-current is prioritized; FJX3906TF remains optimal for cost-sensitive volume designs with wider gain tolerance |
| DXT3906-7-F | SC-59 (SOT-23) package, same electrical specs, but larger footprint (2.9 × 1.3 mm vs. 2.1 × 1.25 mm) and higher RθJA (400 °C/W) | Preferred where SOT-23 reflow compatibility or legacy board design reuse is required; not drop-in due to different pad layout | Choose DXT3906-7-F only when existing SOT-23 tooling or assembly infrastructure mandates package continuity |
Compared with MMBT3906LT1G and DXT3906-7-F, the FJX3906TF offers the smallest SC-70 footprint and widest hFE range (60–300), making it ideal for space-constrained, cost-optimized PNP switching where moderate gain variation is acceptable.
Availability
FJX3906TF is available at Aetrix Electronics and suitable for portable DC-DC feedback, LED current sink, and logic level translation requiring stable component supply, consistent parametric performance, and long-term manufacturing continuity.
Supply support for FJX3906TF 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 manufacturer specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.
The FJX3906TF belongs to ON Semiconductor's general-purpose bipolar transistor product line, designed for cost-effective, reliable switching and amplification in battery-powered and space-constrained electronic systems.
FAQ
What is the maximum collector current rating for the FJX3906TF?
The FJX3906TF has a maximum continuous collector current (IC) rating of -200 mA at TA = 25°C. Derating applies above 25°C at 2.8 mW/°C, and actual usable current depends on PCB layout, ambient temperature, and thermal management. The FJX3906TF must be operated within this limit to ensure reliability and avoid thermal runaway in sustained conduction.
Does the FJX3906TF have a documented PNP polarity and what does that imply for circuit design?
Yes, the FJX3906TF is explicitly specified as a PNP epitaxial silicon transistor. This means current flows from emitter to collector when the base is biased ~0.7 V below the emitter voltage. In practice, the FJX3906TF is used for high-side switching or current sinking, requiring reversed voltage polarities compared to NPN devices - a critical consideration when replacing or designing around the FJX3906TF.
What is the typical saturation voltage of the FJX3906TF and how does it affect power efficiency?
The FJX3906TF exhibits VCE(sat) = -0.25 V at IC = -10 mA and IB = -1 mA, and -0.40 V at IC = -50 mA/IB = -5 mA. These low saturation voltages minimize conduction losses - for example, only 2.5 mW dissipated at -10 mA - making the FJX3906TF well-suited for battery-operated systems where efficiency and thermal management are critical design constraints.
Can the FJX3906TF be used in high-frequency applications, and what is its bandwidth limit?
Yes, the FJX3906TF has a current gain bandwidth product (fT) of 250 MHz, indicating capability for RF amplification and fast switching up to approximately 100 MHz in practical circuits. Its 4.5 pF output capacitance and 300 ns turn-off time further support use in audio preamps, clock buffering, and digital signal conditioning - though layout parasitics must be minimized to realize full FJX3906TF bandwidth potential.
Is the FJX3906TF compatible with lead-free reflow soldering processes?
Yes, the FJX3906TF is qualified for lead-free reflow soldering per J-STD-020. Its SC-70 package meets industry-standard moisture sensitivity level (MSL) requirements, and the device is rated for peak reflow temperatures up to 260°C. Proper handling per MSL guidelines is required before assembly, and the FJX3906TF's thermal characteristics (RθJA = 357 °C/W) assume standard FR-4 PCB mounting per JEDEC specifications.
FJX3906TF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- SC-70, SOT-323
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Transistor Type:
- PNP
- Current - Collector (Ic) (Max):
- 200 mA
- Voltage - Collector Emitter Breakdown (Max):
- 40 V
- Vce Saturation (Max) @ Ib, Ic:
- 400mV @ 5mA, 50mA
- Current - Collector Cutoff (Max):
- -
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 100 @ 10mA, 1V
- Power - Max:
- 350 mW
- Frequency - Transition:
- 250MHz
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-323
FJX3906TF FAQ
1.How can I place an order for FJX3906TF through Aetrix?
Please submit a Request for Quotation (RFQ) for FJX3906TF 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 FJX3906TF reliable?
The price and inventory of FJX3906TF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for FJX3906TF is usually 5 days.
3.What payment methods are accepted for FJX3906TF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for FJX3906TF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for FJX3906TF?
FJX3906TF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your FJX3906TF 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 FJX3906TF?
For technical support, including FJX3906TF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your FJX3906TF requirements.
6.How does Aetrix verify that FJX3906TF is sourced from the original manufacturer or authorized distributors?
All FJX3906TF 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 FJX3906TF meets industry standards.
7.What is the process for return or replacement of FJX3906TF?
All FJX3906TF units undergo pre-shipment inspection (PSI). If there is an issue with FJX3906TF, 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 FJX3906TF part is unused and in its original packaging.
Return procedure for FJX3906TF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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